Nature of Interactions at the Interface of Two Water-Saturated Commercial TiO2 Polymorphs

2013

Two commercial TiO2 samples, a 100% anatase and a 100% rutile, were used for the fast field cycling NMR experiments. The results showed a different behavior between the different samples. In particular, water molecules were unbonded to the solid surface for the rutile sample, whereas they appeared to chemically interact with the surface through H-bond formation with the anatase sample. The above findings accord with the generally lower activity of rutile with respect to anatase reported in literature for photocatalytic oxidation reactions in water. The difficulty of water to interact with rutile surface, indeed, could hinder the formation of OH radicals, which are the most important oxidant…

Synthesis and thermoelectric characterisation of bismuth nanoparticles

2009

An effective method of preparation of bismuth nanopowders by thermal decomposition of bismuth dodecyl-mercaptide Bi(SC12H25)3 and preliminary results on their thermoelectric properties are reported. The thermolysis process leads to Bi nanoparticles due to the efficient capping agent effect of the dodecyl-disulfide by-product, which strongly bonds the surface of the Bi clusters, preventing their aggregation and significantly reducing their growth rate. The structure and morphology of the thermolysis products were investigated by differential scanning calorimetry, thermogravimetry, X-ray diffractometry, 1H nuclear magnetic resonance spectroscopy, scanning electron microscopy, and energy dispe…

DSC study on hyaluronan drying and hydration

2011

Abstract The processes of hyaluronan (HYA) drying and hydration were studied using differential scanning calorimetry. In the first approach the isoconversional Kissinger–Akahita–Sunose (KAS) method was applied in order to determine actual activation energies of evaporation of pure water and water from concentrated HYA solutions. Since the evaporation is a single-step process, the activation energies for pure water provided results consistent with tabulated values of evaporation enthalpies. In the course of water evaporation from hyaluronan solution a break in increasing enthalpy followed by a decrease below 0.34 g of water per 1 g of HYA was observed. This result confirmed earlier observati…

ChemInform Abstract: Environmental NMR: Fast-Field-Cycling Relaxometry

2016

Fast-field-cycling (FFC) NMR relaxometry deals with the variation of the spin–lattice relaxation times (T1) in a complex system, as the strength of the applied magnetic field is changed. Information about molecular dynamics can be achieved. Until now, only model theories for FFC NMR relaxometry have been developed for polymer and material sciences. Just a few applications have been performed in the environmental sciences. These mainly deal with soil porosity, rock permeability, biomass transformations, and natural organic matter dynamics. Further, FFC NMR relaxometry can also be applied to monitor the environmental fate of contaminants, to understand the dynamics of nutrients at the soil–pl…

Applicability of solid state fast field cycling NMR relaxometry in understanding relaxation properties of leaves and leaf-litters

2011

Abstract Inversion recovery high field solid state (SS) 1H NMR spectroscopy and fast field cycling (FFC) NMR relaxometry have been applied on dried leaves and leaf-litters from a reafforestated area in central Sicily (Italy) in order to evaluate relaxation properties in both slow ( 1 ≪ ω 0 2 τ C 2 ) and fast ( 1 ≫ ω 0 2 τ C 2 ) motion regimes. Namely, SS 1H NMR spectroscopy (i.e. slow motion regime conditions) revealed that two relaxation components (a fast and a slow one) can be identified in all the leaves and leaf-litter samples. The fast component was assigned to small sized plant metabolites, whereas the slow one was attributed to slowly tumbling macropolymeric molecules. FFC NMR relax…

Influence of land use on the characteristics of humic substances in some tropical soils of Nigeria

2005

Summary In highly weathered tropical conditions, soil organic matter is important for soil quality and productivity. We evaluated the effects of deforestation and subsequent arable cropping on the qualitative and quantitative transformation of the humic pool of the soil at three locations in Nigeria. Cultivation reduced the humic pool in the order: acetone-soluble hydrophobic fraction (HE) > humic acid (HA) > humin (HU) > fulvic acid (FA), but not to the same degree at all three sites. The C and N contents, as well as the C/N ratios of humic extracts, were large and not substantially influenced by land use. The δ13C values of the humic extracts were invariably more negative in forested soil…

1H NMR-Based Metabolomics to Assess the Impact of Soil Type on the Chemical Composition of Nero d’Avola Red Wines

2023

: In this study, the soil effect on the micro-component composition of Nero d'Avola wines obtained from different locations was investigated through 1H NMR-based metabolomics. Two different approaches were applied: the targeted (TA) and the non-targeted one (NTA). The former differentiated the wines by profiling (i.e., by identifying and quantifying) a number of different metabolites. The latter provided wine fingerprinting by processing the entire spectra with multivariate statistical analysis. NTA also allowed investigation of the hydrogen bond network inside wines via the analysis of 1H NMR chemical shift dispersions. Results showed that the differences among wines were due not only to t…

Interactions between 2-Aminobenzothiazole and Natural Organic Matter as Evidenced by CPMAS Nitrogen-15 NMR Spectroscopy

2009

Cross-polarization magic angle spinning (CPMAS) 15N nuclear magnetic resonance (NMR) spectroscopy was used to study the interactions between 2-aminobenzothiazole (ABT) and natural organic matter in the presence of the natural enzyme laccase and synthetic air. Through the use of synthesized model compounds, we were able to confirm previous findings by CPMAS 13C NMR spectroscopy that showed the formation of covalent amide bonds. We also provide evidence of the presence of two additional H bonds between ABT and the natural organic matter. Both H bonds involved the amino and thiazole groups of ABT.

Recent Developments in Understanding Biochar’s Physical–Chemistry

2021

Biochar is a porous material obtained by biomass thermal degradation in oxygen-starved conditions. It is nowadays applied in many fields. For instance, it is used to synthesize new materials for environmental remediation, catalysis, animal feeding, adsorbent for smells, etc. In the last decades, biochar has been applied also to soils due to its beneficial effects on soil structure, pH, soil organic carbon content, and stability, and, therefore, soil fertility. In addition, this carbonaceous material shows high chemical stability. Once applied to soil it maintains its nature for centuries. Consequently, it can be considered a sink to store atmospheric carbon dioxide in soils, thereby mitigat…

Nuclear Magnetic Resonance with Fast Field-Cycling Setup: A Valid Tool for Soil Quality Investigation

2020

Nuclear magnetic resonance (NMR) techniques are largely employed in several fields. As an example, NMR spectroscopy is used to provide structural and conformational information on pure systems, while affording quantitative evaluation on the number of nuclei in a given chemical environment. When dealing with relaxation, NMR allows understanding of molecular dynamics, i.e., the time evolution of molecular motions. The analysis of relaxation times conducted on complex liquid–liquid and solid–liquid mixtures is directly related to the nature of the interactions among the components of the mixture. In the present review paper, the peculiarities of low resolution fast field-cycling (FFC) NMR rela…

Hydration and water holding properties of cross-linked lignite humic acids

2014

Abstract Lignite and lignite humic acids, which are used as soil amendments sometimes, are supposed to improve soil properties such as water holding capacity. The structure of those materials is composed of various organic molecules stabilized mostly by weak interactions. Therefore, excess of water causes only partial swelling, but most of the physical structure is destabilized. This accelerates the desiccation and hampers their application as natural hydrogel-like substances. In order to stabilize the structure of lignite humic acids and improve the water holding capacity, we applied formaldehyde cross-linking procedure based on covalent coupling of aromatic humic acids moieties. By combin…

Organic coating on biochar explains its nutrient retention and stimulation of soil fertility

2017

Amending soil with biochar (pyrolized biomass) is suggested as a globally applicable approach to address climate change and soil degradation by carbon sequestration, reducing soil-borne greenhouse-gas emissions and increasing soil nutrient retention. Biochar was shown to promote plant growth, especially when combined with nutrient-rich organic matter, e.g., co-composted biochar. Plant growth promotion was explained by slow release of nutrients, although a mechanistic understanding of nutrient storage in biochar is missing. Here we identify a complex, nutrient-rich organic coating on co-composted biochar that covers the outer and inner (pore) surfaces of biochar particles using high-resoluti…

Evaluation of adsorption ability of Cyclodextrin-Calixarene Nanosponges towards Pb2+ ion in aqueous solution

2021

Abstract Different cyclodextrin-calixarene nanosponges (CyCaNSs) have been characterized by means of FFC-NMR relaxometry, and used as sorbents to remove Pb2+ ions from aqueous solutions. Considering that the removal treatments may involve polluted waters with different characteristics, the adsorption experiments were performed on solutions without and with the addition of background salts, under different operational conditions. The adsorption abilities and affinities of the nanosponges towards Pb2+ ions were investigated by measuring the metal ion concentration by means of Inductively Coupled Plasma Emission Spectroscopy (ICP-OES) and Differential Pulse Anodic Stripping Voltammetry (DP-ASV…

Effect of RF Field Inhomogeneity and Sample Restriction on Spectral Resolution of CP/MAS-13C NMR Spectra of Natural Organic Matter

2010

It is well known that the induced B1 magnetic field in an NMR coil is inhomogeneously distributed. However, this issue has so far received little attention in the field of environmental NMR. As this research field often aims at quanti- tative results as well as relaxation phenomena, the repercussions of such inhomogeneity on peak integrals and relaxation times need to be taken into account. The objective of the present study was to test standard recording conditions on different sample positions in an NMR coil in order to determine the effect of the RF field inhomogeneity on the spectrum of a molecularly complex humic material and on some standard molecules of known structure and conformati…

Comparing different processing methods in apple slice drying. Part 2 solid-state Fast Field Cycling 1H-NMR relaxation properties, shrinkage and chang…

2019

The objective of this paper was to study the effects of different drying methods that are: microwave (MW), hot air (HA) and a combination of both (HY), on the 1H-NMR relaxation properties, shrinkage and volatile compounds of Golden Delicious apple slices. Fast field cycling NMR relaxometry reveals that the HA samples dried at different temperatures (65 and 75 °C) appear to contain less restrained water as compared to the sample obtained by MW heating at the same temperatures. In fact, the longitudinal relaxation rates (T1) of the water molecules in the HA dried slices resulted shorter than those measured for the MW dried samples, thereby revealing that in the MW slices, water molecules beha…

Increased conformational rigidity of humic substances by oxidative biomimetic catalysis

2005

A synthetic water-soluble meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate of iron(III) chloride, Fe(TDCPPS)Cl, was employed as a biomimetic catalyst in the oxidative coupling of terrestrial humic materials. High-performance size-exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance (CPMAS-(13)C NMR), electron paramagnetic resonance (EPR), and diffuse reflectance infrared spectroscopy (DRIFT) were used to follow conformational and structural changes brought about in different humic materials by the oxidative coupling. Increase in apparent weight-average molecular weight (Mw(a)) occurred invariably for all humic substances with the oxidative polymerization catalyzed …

Small-sized platinum nanoparticles in soil organic matter: Influence on water holding capacity, evaporation and structural rigidity

2019

Abstract Engineered and anthropogenic nanoparticles represent a new type of pollutants. Up until now, many studies have reported its adverse effect on biota, but the potential influence on the properties and functions of environmental compartments has largely been ignored. In this work, the effect of Pt nanoparticles on the functions and properties of model soil organic matter has been studied. Using differential scanning calorimetry and molecular modeling, the effect of a wide range of 3 nm Pt nanoparticles concentrations on water holding capacity, the strength of water binding, the stability of water molecule bridges and the content of aliphatic crystallites was studied. It was found that…

1H NMR Spectroscopy with Multivariate Statistical Analysis as a Tool for a Rapid Screening of the Molecular Changes Occurring During Micro-Oxygenatio…

2008

A red wine from Aglianico vine was subjected to a micro-oxygenation procedure for five weeks. The wine was weekly sampled together with a non micro-oxygenated control and extracted with di-ethyl-ether in order to simplify NMR analyses. In fact, 1 H NMR spectra of the whole wine samples were dominated by water and ethanol signals which pre- vented visibility of the resonances generated by the less concentrated wine components. The 1 H NMR analyses of the di- ethyl-ether extracts revealed an increase of the amount of oxygen-containing materials. Such increase was attributed to a wine ageing process which resulted, hence, fastened by application of micro-oxygenation.

Look for methods, not conclusions

2019

Qualunque sia l'esito effettivo di un'indagine su un caso di presunta manipolazione dei dati, ci sono alcuni principi fermi che sono sempre veri e alcuni errori che devono essere evitati.

CPMAS 13C NMR Characterization of Leaves and Litters from the Reafforestated Area of Mustigarufi in Sicily (Italy)

2010

Reafforestation is generally based on the planting of exotic fast growing tree species suitable for adapting to even harsh environments. Once the introduced plants ameliorate soil conditions, they can be progressively replaced by au- tochthonous plant species. Reafforestation is applied worldwide. However, only few studies on the effect of reafforesta- tion on lands from Mediterranean regions are available. This paper reports the characterization by cross polarization 13C NMR spectroscopy of fresh leaves and superficial litters from a reafforestated area in central Sicily (Italy). NMR assign- ment is attempted. A differentiation among the molecular systems within leaves and litters is also …

Differentiation among dairy products by combination of fast field cycling NMR relaxometry data and chemometrics

2021

A set of commercial milk and Sicilian cheeses was analysed by a combination of fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry and chemometrics. The NMR dispersion (NMRD) curves were successfully analysed with a mathematical model applied on Parmigiano-Reggiano (PR) cheese. Regression parameters were led back to the molecular components of cheeses (water trapped in casein micelles, proteins and fats) and milk samples (water belonging to hydration shells around dispersed colloidal particles of different sizes and bulk water). The application of chemometric analysis on relaxometric data enabled differentiating milk from cheeses and revealing differences within the two sa…

Standardizing the use of fast-field cycling NMR relaxometry for measuring hydrological connectivity inside the soil

2019

Hydrological connectivity inside the soil (HCS) is applied to study the effects of heterogeneities in complex environmental systems. It refers to both the spatial patterns inside the soil (i.e., structural connectivity [SC]) and the physical–chemical processes at a molecular level (i.e., functional connectivity [FC]). NMR relaxometry has been already applied to assess both SC and FC components of the HCS by defining SC and FC indexes. Here, fast-field cycling NMR relaxometry has been applied on a water suspended soil and a sediment to optimize the conditions to standardize the technique. Proton Larmor frequencies (ωL) from 0.01 to 25 MHz were used on samples suspended in three different rat…

Research and Application of Biochar in Europe

2015

Iodofluorination of alkenes and alkynes promoted by iodine and 4-iodotoluene difluoride

2006

It was found that a mixt. of mol. iodine and 4-iodotoluene difluoride are useful to generate in situ the electrophilic iodine/nucleophilic fluorine (IF) couple that was able to add in a Markovnikov fashion and with prevalent anti-stereoselectivity to various alkenes and alkynes.

Interaction of a Recombinant Prion Protein with Organo-Mineral Complexes as Assessed by FT-IR and CPMAS 13C NMR Analysis

2010

Prion proteins are considered as the main agents for the Transmissible Spongiform Encephalopathies (TSE). The misfolded form, PrP Sc , which is also indicated as the etiological agent for TSE, exhibits high resistance to degradation in environmental processes. Soil contamination by prion proteins is a real environmental issue since contaminated soils can become potential reservoir and diffuser for TSE infectivity. In this work, the interaction of prion protein with organo- mineral complexes was studied by using a recombinant non pathogenic prion protein and a model soil system. This latter was represented by a soil manganese mineral coated with polymerized catechol. FT-IR spectra showed ami…

A multivariate statistical and relaxometry approach to study the provenance and traceability of dairy products

Water dynamics and its role in structural hysteresis of dissolved organic matter

2016

Knowledge of structural dynamics of dissolved organic matter (DOM) is of paramount importance for understanding DOM stability and role in the fate of solubilized organic and inorganic compounds (e.g., nutrients and pollutants), either in soils or aquatic systems. In this study, fast field cycling (FFC) (1)H NMR relaxometry was applied to elucidate structural dynamics of terrestrial DOM, represented by two structurally contrasting DOM models such as Suwanee River (SRFA) and Pahokee peat (PPFA) fulvic acids purchased by the International Humic Substance Society. Measurement of NMR relaxation rate of water protons in heating-cooling cycles revealed structural hysteresis in both fulvic acids. I…

Changes of humic substances characteristics from forested to cultivated soils in Ethiopia

2006

The dynamics of the stable fractions of soil organic matter (SOM), the humic substances, has been rarely studied in tropical soils. We evaluated extraction yields, elemental composition, isotopic d 13 C abundance and solid-state 13 C NMR spectra of humic fractions isolated from five forested and cultivated soils in Ethiopia in order to assess the influence of deforestation and subsequent cultivation on the composition of humic fractions. In all locations, humic (HA) and fulvic (FA) acids, humin (HU) and a humic hydrophobic fraction extracted with an acetone–HCl solution (HE) were decreased as a result of deforestation and cultivation, but the magnitude of decrease was site-specific. While t…

Effect of pruning-derived biochar on heavy metals removal and water dynamics

2014

Biomass-derived biochar is considered as a promising heavy metal adsorbent, due to abundance of polar functional groups, such as carboxylic, hydroxyl, and amino groups, which are available for heavy metal removal. The aims of this study were to evaluate the effectiveness of an orchard pruning-derived biochar in removing some heavy metals (through the evaluation of isotherms) and to study water dynamics at the solid-liquid interface as affected by heavy metal adsorption (through an innovative nuclear magnetic resonance (NMR) relaxometry approach). Both isotherms and NMR spectra revealed that Pb and Cr showed a good affinity for the biochar surface (Pb > Cr), while Cu was less affine. Accordi…

Fast field cycling NMR relaxometry characterization of biochars obtained from an industrial thermochemical process

2012

Biochar has unique properties which make it a powerful tool to increase soil fertility and to contribute to the decrease of the amount of atmospheric carbon dioxide through the mechanisms of C sequestration in soils. Chemical and physical biochar characteristics depend upon the technique used for its production and the biomass nature. For this reason, biochar characterization is very important in order to address its use either for agricultural or environmental purposes. Three different biochars obtained from an industrial gasification process were selected in order to establish their chemical and physical peculiarities for a possible use in agronomical practices. They were obtained by char…

Structure alteration of a sandy-clay soil by biochar amendments

2014

The aim of the present study was to investigate structure alterations of a sandy-clay soil upon addition of different amounts of biochar (f bc ). All the f bc samples were analyzed by high energy moisture characteristic (HEMC) technique and 1H nuclear magnetic resonance (NMR) relaxometry. HEMC was applied in order to evaluate aggregate stability of biochar-amended soil samples. 1H NMR relaxometry experiments were conducted for the evaluation of the pore distributions through the investigation of water dynamics of the same samples. The HEMC technique revealed improvement in aggregate stability through measurements of the amount of drainable pores and the stability ratio. The latter increased…

Soil-Water Interactions Unveiled by Fast Field Cycling NMR Relaxometry

2017

Applications of fast field cycling NMR relaxometry

2021

Abstract Fast field cycling (FFC) NMR relaxometry is emerging as a powerful tool to investigate physical chemistry properties of many systems in a number of different scientific fields. As an example, it is used to investigate environmental issues such as soil erosion, water, and nutrient dynamics in environmentally relevant porous systems, to discriminate among different kinds of foodstuff in order to understand possible source of adulteration and fraud, to evaluate the properties of new materials, and much more. In the present study, an overview about the possible applications of FFC NMR relaxometry is given. The paper is not intended to be exhaustive. Rather, it is thought to provide an …

Microstructural and associated chemical changes during the composting of a high temperature biochar: Mechanisms for nitrate, phosphate and other nutr…

2018

Recent studies have demonstrated the importance of the nutrient status of biochar and soils prior to its inclusion in particular agricultural systems. Pre-treatment of nutrient-reactive biochar, where nutrients are loaded into pores and onto surfaces, gives improved yield outcomes compared to untreated biochar. In this study we have used a wide selection of spectroscopic and microscopic techniques to investigate the mechanisms of nutrient retention in a high temperature wood biochar, which had negative effects on Chenopodium quinoa above ground biomass yield when applied to the system without prior nutrient loading, but positive effects when applied after composting. We have compared non-co…

Assessing hydrological connectivity inside a soil by fast-field-cycling nuclear magnetic resonance relaxometry and its link to sediment delivery proc…

2017

Connectivity is a general concept used to represent the processes involving a transfer of matter among the elements of an environmental system. The expression “hydrological connectivity inside the soil” has been used here to indicate how spatial patterns inside the soil (i.e., the structural connectivity) interact with physical and chemical processes (i.e., the functional connectivity) in order to determine the subsurface flow (i.e., the water transfer), thereby explaining how sediment transport due to surface runoff (i.e., the soil particle transfer) can be affected. This paper explores the hydrological connectivity inside the soil (HCS) and its link to sediment delivery processes at the p…

Advanced CPMAS-13C NMR techniques for molecular characterization of size-separated fractions from a soil humic acid

2006

A humic acid extracted from a volcanic soil was subjected to preparative high-performance size-exclusion chromatography (HPSEC) to reduce its molecular complexity and eleven different size fractions were obtained. Cross-polarization magic-angle spinning 13C NMR (CPMAS 13C NMR) analysis performed with variable contact-time (VCT) pulse sequences showed that the largest molecular-size fractions contained aromatic, alkyl, and carbohydrate-like components. The carbohydrate-like content and the alkyl chain length seemed to decrease with decreasing molecular size. Progressive reduction of aromatic carbon atoms was also observed with decreasing molecular size of the separated fractions. Mathematica…

Biochar from Wood Chips and Corn Cobs for Adsorption of Thioflavin T and Erythrosine B.

2022

Biochars from wood chips (WC) and corn cobs (CC) were prepared by slow pyrolysis and used for sorption separation of erythrosine B (EB) and thioflavin T (TT) in batch experiments. Biochar-based adsorbents were extensively characterized using FTIR, XRD, SEM-EDX, and XPS techniques. The kinetics studies revealed that adsorption on external surfaces was the rate-limiting step for the removal of TT on both WC and CC biochar, while intraparticle diffusion was the rate-limiting step for the adsorption of EB. Maximal experimental adsorption capacities Qmaxexp of TT reached 182 ± 5 (WC) and 45 ± 2 mg g−1 (CC), and EB 12.7 ± 0.9 (WC) and 1.5 ± 0.4 mg g−1 (CC),…

Soil remediation: humic acids as natural surfactants in the washings of highly contaminated soils

2005

The remediation of the highly contaminated site around the former chemical plant of ACNA (near Savona) in Northern Italy is a top priority in Italy. The aim of the present work was to contribute in finding innovative and environmental-friendly technology to remediate soils from the ACNA contaminated site. Two soils sampled from the ACNA site (A and B), differing in texture and amount and type of organic contaminants, were subjected to soil washings by comparing the removal efficiency of water, two synthetic surfactants, sodium dodecylsulphate (SDS) and Triton X-100 (TX100), and a solution of a natural surfactant, a humic acid (HA) at its critical micelle concentration (CMC). The extraction …

Recovering ammonium by treated and untreated zeolitic mixtures: A comprehensive experimental and modelling study

2023

The recovery of ammonium (NH4+) from aqueous solutions by zeolite is attractive. In this study, the physicalchemistry of NH4+ adsorption process from aqueous solution by two zeolitic mixtures, either treated or not treated with NaCl, was assessed. Results suggested that the zeolitic mixture richer in mordenite and with high specific surface area adsorbed more NH4+ than the one richer in clinoptilolite and heulandite showing a lower specific surface area. NaCl treatment increased the amount of NH4+ adsorbed by the zeolitic mixtures. The higher amount of NH4+ adsorbed by the zeolitic mixtures treated with NaCl was explained by the low/high density water model accounting for cation exchange am…

NMR-investigation of the mechanism of silver mercaptide thermolysis in amorphous polystyrene

2007

Polymer-embedded silver clusters have been prepared by thermal decomposition of silver dodecylmercaptide previously dissolved in amorphous polystyrene. The morphology and structure of silver clusters have been determined by transmission electron microscopy (TEM) and large angle X-ray diffractometry (XRD), respectively. The mechanism involved in the thermolysis reaction was elucidated by different NMR techniques. The thermolysis produced thiol-derivatized silver clusters (i.e., silver clusters coated with a self-organized thiol monolayer, Agx(SC12H25)y) and had the effect of increasing the branching degree of polystyrene due to enhanced cross-linking.

Preface to the Special Issue on ‘‘Applications and developments of magnetic resonance techniques in geosciences’’

2011

O-Alkylation of a lignite humic acid by phase-transfer catalysis

2006

A mild phase-transfer catalytic reaction has been conducted to O-alkylate the acidic functions of a lignite humic acid (HA), using tetrabutylammonium hydroxide as the phase-transfer catalyst. The HA acidic functional groups were made to react, in tetrahydrofuran, by nucleophilic substitution with several alkyl halides-methyl iodide, and ethyl, propyl, and butyl, and benzyl bromide. The occurrence of the O-alkylation reaction was assessed by elemental analysis and 1H NMR, CPMAS 13C NMR, and FTIR spectroscopy. Bonding of alkyl groups increased the carbon and hydrogen content and the H/C ratios of all the humic reaction products. Increased nitrogen in the reaction products suggested incomplete…

Spectroscopic and conformational properties of size-fractions separated from a lignite humic acid

2007

Abstract A lignite humic acid (HA) was fractionated by preparative high performance size-exclusion chromatography (HPSEC) in seven different size-fractions. The size-fractions were characterized by cross polarization (CP) magic angle spinning (MAS) 13 C NMR spectroscopy and a further analytical HPSEC elution under UV and fluorescence detection. The alkyl hydrophobic components mainly distributed in the largest molecular-size-fraction, whereas the amount of oxidized carbons increased with decreasing size of fractions. Cross polarization time ( T CH ) and proton spin-lattice relaxation time in the rotating frame ( T 1 ρ (H)) were measured from variable contact time (VCT) experiments. The bulk…

Biochar based remediation of water and soil contaminated by phenanthrene and pentachlorophenol

2017

Abstract Phenanthrene (Phe) and pentachlorophenol (PCP) are classified as persistent organic pollutants and represent serious concern for the environment as they are toxic and ubiquitous. Biochar based remediation is an emerging technology used in water and soil contamination. In this study we used poplar (BP) and conifer (BC) biochars to remediate water and soil contaminated by Phe and PCP. BP and BC were able to remove completely either Phe or PCP from contaminated water within one to three days. When biochar was confined in a porous membrane, BC and BP maintained their sorption efficiency for several remediation cycles. However, in these conditions BC allowed faster Phe removal. In soil …

Effects of Humic Substances and Soya Lecithin on the Aerobic Bioremediation of a Soil Historically Contaminated by Polycyclic Aromatic Hydrocarbons (…

2004

The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradation of PAHs in soils can be enhanced by employing surface-active agents. However, chemical surfactants are often recalcitrant and exert toxic effects in the amended soils. The effects of two biogenic materials as pollutant-mobilizing agents on the aerobic bioremediation of an aged-contaminated soil were investigated here. A soil historically contaminated by about 13 g kg(-1) of a large variety of PAHs, was amended with soya lecithin (SL) or humic substances (HS) at 1.5% w/w and incubated in aerobic solid-phas…

Adsorption of dissolved organic matter on clay minerals as assessed by infra-red, CPMAS 13C NMR spectroscopy and low field T1 NMR relaxometry

2011

Abstract Dissolved organic matter (DOM) is a very important environmental constituent due to its role in controlling factors for soil formation, mineral weathering and pollutant transport in the environment. Prediction of DOM physical–chemical properties is achieved by studying its chemical structure and spatial conformation. In the present study, dissolved organic matter extracted from compost obtained from the organic fraction of urban wastes (DOM-P) has been analysed by FT-IR, CPMAS 13C NMR spectroscopy and 1H T1 NMR relaxometry with fast field cycling (FFC) setup. While the first two spectroscopic techniques revealed the chemical changes of dissolved organic matter after adsorption eith…

Influence of Adsorbed Water on the Activation Energy of Model Photocatalytic Reactions

2017

Two commercial (Merck and Sigma-Aldrich) and two home prepared (HP05 and HP05C) powdered TiO2 photocatalysts were investigated by fast field cycling nuclear magnetic resonance experiments in order to explore the nature of the interactions between water and the solid surfaces. The results were related to the activation energies determined at temperatures ranging from 303 to 353 K for the photocatalytic oxidation in water of three model molecules presenting different interactions with the solid surface (catechol, phenol, and metylbenzoate). The photoactivity results at different temperatures were comparable to each other because the runs were carried out while keeping constant the concentrati…

Mechanisms of Organic Coating on the Surface of a Poplar Biochar

2017

Background: Recent studies highlighted that biochar efficiency to improve soil fertility is enhanced after it is blended with fresh organic materials. It was suggested that organic coating of inner-porous biochar surfaces acts as a kind of “glue” for plant-nutrients, thereby allowing their slow release towards plant-roots and/or microorganisms. Objective: The aim of the present study is to improve the understanding of the nature of the interactions between fresh organic matter and a poplar biochar. Method: Two fluorinated organic models were used as target molecules in order to apply heteronuclear (i.e. 19F) fast field cycling (FFC) NMR relaxometry. Results: The results suggest that organic…

Nature of water-biochar interface interactions

2012

A poplar biochar obtained by an industrial gasification process was saturated with water and analyzed using fast field cycling (FFC) NMR relaxometry in a temperature range between 299 and 353 K. Results revealed that the longitudinal relaxation rate increased with the increment of the temperature. This behavior was consistent with that already observed for paramagnetic inorganic porous media for which two different relaxation mechanisms can be accounted for: outer- and inner-sphere mechanisms. The former is due to water diffusing from the closest approach distance to infinity, whereas the second is due to water interacting by nonconventional H-bonds to the porous surface of the solid materi…

Dynamics of hyaluronan aqueous solutions as assessed by fast field cycling NMR relaxometry.

2010

Fast field cycling (FFC) NMR relaxometry has been used to study the conformational properties of aqueous solutions of hyaluronan (HYA) at three concentrations in the range 10 to 25 mg mL(-1). Results revealed that, irrespective of the solution concentration, three different hydration layers surround hyaluronan. The inner layer consists of water molecules strongly retained in the proximity of the HYA surface. Because of their strong interactions with HYA, water molecules in this inner hydration layer are subject to very slow dynamics and have the largest correlation times. The other two hydration layers are made of water molecules which are located progressively further from the HYA surface.…

Effect of Heating Time and Temperature on the Chemical Characteristics of Biochar from Poultry Manure

2014

Poultry manure (PM) chars were obtained at different temperatures and charring times. Chemical-physical characterization of the different PM chars was conducted by cross-polarization magic angle spinning (CPMAS) (13)C NMR spectroscopy and thermal analysis. CPMAS (13)C NMR spectra showed that the chemical composition of PM char is dependent on production temperature rather than on production duration. Aromatic and alkyl domains in the PM chars obtained at the lowest temperatures remained unchanged at all heating times applied for their production. The PM char obtained at the highest temperature consisted only of aromatic structures having chemical nature that also appeared invariant with hea…

Effects of afforestation with four unmixed plant species on the soil–water interactions in a semiarid Mediterranean region (Sicily, Italy)

2012

Purpose An assessment of the effect of plant cover on the properties of four afforested soils in central Sicily was performed with the aim of discriminating among them after 60 years of afforestation. Materials and methods Chemical and biochemical soil analyses were coupled to fast field cycling (FFC) NMR relaxation investigations in order to monitor surface interactions of water in water-saturated soils. Results and discussion The traditional soil analyses revealed that the most stable soil properties such as soil texture and pH are not affected by 60 years of afforestation. Soils developed under eucalyptus trees showed larger amounts of hydrophilic organic matter as compared to the soils …

Fourfold Increase in Pumpkin Yield in Response to Low-Dosage Root Zone Application of Urine-Enhanced Biochar to a Fertile Tropical Soil

2015

A widely abundant and invasive forest shrub, Eupatorium adenophorum, was pyrolyzed in a cost-efficient flame curtain kiln to produce biochar. The resulting biochar fulfilled all the requirements for premium quality, according to the European Biochar Certificate. The biochar was either applied alone or mixed with fresh cow urine (1:1 volume) to test its capacity to serve as slow release fertilizer in a pumpkin field trial in Nepal. Treatments included cow-manure compost combined with (i) urine-only; (ii) biochar-only or (iii) urine-loaded biochar. All materials were applied directly to the root zone at a biochar dry matter content of 750 kg·ha−1 before seeding. The urine-biochar treatment le…

Mechanisms of Water Interaction with Pore Systems of Hydrochar and Pyrochar from Poplar Forestry Waste

2014

The aim of this study was to understand the water-surface interactions of two chars obtained by gasification (pyrochar) and hydrothermal carbonization (hydrochar) of a poplar biomass. The two samples revealed different chemical compositions as evidenced by solid state (13)C NMR spectroscopy. In fact, hydrochar resulted in a lignin-like material still containing oxygenated functionalities. Pyrochar was a polyaromatic system in which no heteronuclei were detected. After saturation with water, hydrochar and pyrochar were analyzed by fast field cycling (FFC) NMR relaxometry. Results showed that water movement in hydrochar was mainly confined in very small pores. Conversely, water movement in py…

Dynamics of cross polarization in solid state nuclear magnetic resonance experiments of amorphous and heterogeneous natural organic substances

2008

Nuclear magnetic resonance (NMR) experiments on carbon-13 in the solid state were done with cross polarization (CP) and magic angle spinning (MAS) in order to overcome the low NMR sensitivity of (13)C and the chemical shift anisotropy, respectively. In the present research, CPMAS (13)C-NMR spectra were collected by modulating the contact time needed for cross polarization (variable contact times experiments, VCT) on two different humic acids (a soil-HA and a coal-HA). VCT data were fitted by a model containing either a monotonic or a non-monotonic cross polarization term. The non-monotonic model, which fitted the experimental results better than the monotonic one, provided two cross-polariz…

Water Dynamics at the Solid-Liquid Interface to Unveil the Textural Features of Synthetic Nanosponges.

2020

A Fast-Field-Cycling NMR investigation was carried out on a set of polyurethane cyclodextrin nanosponges, in order to gain information on their textural properties, which have been proven to be quite difficult to assess by means of ordinary porosimetric techniques. Experiments were performed on both dry and wet samples, in order to evaluate the behavior of the “non-exchangeable” C-bound 1H nuclei, as well as the one of the mobile protons belonging to the skeletal hydroxyl groups and the water molecules. The results acquired for the wet samples accounted for the molecular mobility of water molecules within the channels of the nanosponge network, leading back to the possible pore size distrib…

Combined proton NMR wideline and NMR relaxometry to study SOM-water interactions of cation-treated soils

2013

Abstract Focusing on the idea that multivalent cations affect SOM matrix and surface, we treated peat and soil samples by solutions of NaCl, CaCl2 or AlCl3. Water binding was characterized with low field 1H-NMR-relaxometry (20 MHz) and 1H wideline NMR spectroscopy (400 MHz) and compared to contact angles. From 1H wideline, we distinguished mobile water and water involved in water molecule bridges (WaMB). Large part of cation bridges (CaB) between SOM functional groups are associated with WaMB. Unexpectedly, 1H NMRrelaxometry relaxation rates suggest that cross-linking in the Al-containing peat is not stronger than that by Ca. The relation between percentage of mobile water and WaMB water in…

FFC-NMR techniques for assessing the texture features of nanosponges

2021

Nanosponges (NSs), i.e. hyper cross linked polymeric materials obtained by reticulating cyclodextrin units with suitable linker units, constitute an emerging class of functional materials, due to their easy synthesis and chemical modification, and to their tunable absorption and controlled release abilities as well. NSs are supposed to possess a thick network of nanochannels in their highly disordered structure. However, their textural features (average pore size, specific surface and specific pore volume) are quite difficult to estimate, and classical evaluation methodologies (N2 absorption isotherms analyzed by BET or BJH methods, or dye absorption isotherms1) have afforded questionable r…

Water dynamics in different biochar fractions

2015

Biochar is a carbonaceous porous material deliberately applied to soil to improve its fertility. The mechanisms through which biochar acts on fertility are still poorly understood. The effect of biochar texture size on water dynamics was investigated here in order to provide information to address future research on nutrient mobility towards plant roots as biochar is applied as soil amendment. A poplar biochar has been stainless steel fractionated in three different textured fractions (1.0–2.0 mm, 0.3–1.0 mm and <0.3 mm, respectively). Water-saturated fractions were analyzed by fast field cycling (FFC) NMR relaxometry. Results proved that 3D exchange between bound and bulk water predominant…

Environmental NMR: Fast-field-cycling Relaxometry

1996

Fast-field-cycling (FFC) NMR relaxometry deals with the variation of the spin–lattice relaxation times (T1) in a complex system, as the strength of the applied magnetic field is changed. Information about molecular dynamics can be achieved. Until now, only model theories for FFC NMR relaxometry have been developed for polymer and material sciences. Just a few applications have been performed in the environmental sciences. These mainly deal with soil porosity, rock permeability, biomass transformations, and natural organic matter dynamics. Further, FFC NMR relaxometry can also be applied to monitor the environmental fate of contaminants, to understand the dynamics of nutrients at the soil–pl…

Cooking influence on physico-chemical fruit characteristics of eggplant (Solanum melongena L.)

2016

Physico-chemical traits of three eggplant genotypes ("Tunisina", "Buia" and "L 305") were evaluated before and after two cooking treatments (grilling and boiling). Different genotypes revealed different changes after cooking, with "Tunisina" showing a better retention of phytochemicals with respect to other two genotypes. The main physical phenomena were water loss during grilling, and dry matter loss after boiling. Chlorogenic acid, the main phenolic in eggplant, resulted higher in grilled samples, while delphinidin glycosides resulted more retained in boiled samples. Glycoalkaloids, thiols and biogenic amines were generally stable, while 5-hydroxy-methyl-furfural was found only in grilled…

Effect of Organic Amendments on the Evolution of Soil Organic Matter in Soils Stressed by Intensive Agricultural Practices

2013

Losses of soil organic carbon often occur because of intensive agricultural practices that lead to removal of organic carbon following harvest production and to insufficient inputs. Organic amendments can be a very appropriate matrix for enhancing organic carbon content in very stressed agricultural soils. In general, they, enhancing soil organic matter, play an important role in environmental matrices due, for example, to their capacity in retaining water, in interacting with organic and inorganic pollutants, and in enhancing nutrient availability to plants. For this reason, the understanding of the mechanisms with which organic amendments interact with other chemicals in the environment i…

State of the art of CPMAS 13C-NMR spectroscopy applied to natural organic matter

2004

A number of different techniques are presently available for characterizing humified natural organic matter (NOM). Carbon-13 nuclear magnetic resonance spectroscopy (13C-NMR) in the solid state using cross-polarization (CP) and magic angle spinning (MAS) represents the most powerful experimental approach used to collect direct information on the structural and conformational characteristics of humic carbon backbones. Despite the problems due to the presence of paramagnetic impurities and the generally low organic matter concentration, cross-polarization magic angle spinning 13C-NMR spectroscopy (CPMAS 13C-NMR) is applied in soil chemistry and geochemistry mainly because of its relevance in …

Structural and Mechanical Modification Induced by Water Content in Giant Wild Reed (A. donax L.)

2018

Giant wild reed Arundo donax L. is an aggressive agricultural species with remarkable features such as fast-growing, untapped economic potential, eco-friendliness, and high specific properties (e.g., high strength/weight and modulus/weight ratios). Here, the bending properties of giant reed were studied at a molecular level to evaluate the effect of the conditions used during the preparation for their applications (also referred to as treatment conditions). The aim was to achieve new information potentially useful to suggest new possible applications of A. donax L. for structural applications in modern buildings. In this study, green reeds collected in a Sicilian plantation were dried for 2…

Evaluation of the factors affecting direct polarization solid state (31)P-NMR spectroscopy of bulk soils

2008

Summary 31 P-NMR spectroscopy on bulk soils is a powerful tool for the identification of the different phosphorus forms in soils and for the evaluation of the dynamics of soil P. Up to now the majority of the papers dealt with liquid state 31 P-NMR spectroscopy on soluble soil organic substances. Only few papers were addressed to the study of the different phosphorus forms directly in bulk soils. In the present paper, some organic and inorganic phosphates of known structures, which are likely to be present in soil systems, were studied by direct polarization (DP) magic angle spinning (MAS) 31 P-NMR spectroscopy in order to understand the electronic factors responsible for chemical shifts of…

Solid-state 1H-NMR relaxation properties of the fruit of a wild relative of eggplant at different proton Larmor frequencies

2009

1H longitudinal relaxation time profiles (T1) at different proton Larmor frequencies were registered for a solid state plant tissue by using fast field cycling (FFC) nuclear magnetic resonance (NMR) spectroscopy. T1 distributions were obtained and the curves deconvoluted in order to differentiate among the different T1 components. Among the components, two were assigned to hydrophobic (e.g. fatty acids) and hydrophilic (e.g. saccharides) molecular systems, whereas the remaining others were attributed to bulk and bound water. This paper showed for the first time solid state FFC-NMR spectroscopy applied to plant tissue, and revealed that relaxometry is a very promising technique for studying …

Heuristic Algorithm for the Analysis of Fast Field Cycling (FFC) NMR Dispersion Curves

2021

Evaluation of nuclear magnetic relaxation dispersion (NMRD) curves obtained by the fast field cycling nuclear magnetic resonance (FFC-NMR) relaxometry technique is a valuable tool for analyzing the microscopic dynamics of condensed matter systems. However, quantitative data analysis involves several conceptual and practical issues. Moving forward from previous literature approaches, we propose a new analysis method, relying on the elaboration of the inverse integral transform of the NMRD curve. Our approach results in a true heuristic method, able to unambiguously individuate the dynamic domains in the system, thereby avoiding the possible introduction of any element of discretion. The anal…

Structural Characterization of Isomeric Dimers from the Oxidative Oligomerization of Catechol with a Biomimetic Catalyst

2007

In a previous paper, it has been reported about the formation of catechol di-, tri- and tetramers within an oxidative polymerization catalyzed by synthetic water-soluble iron-porphyrin as an efficient alternative to bio-labile natural peroxidase. It has also been demonstrated the occurrence of both C-C and C-O-C coupling mechanisms. However, since the coupling products were determined by mass spectroscopy, the exact bonding position could not have been precisely ascertained for the C-C bonded isomeric dimers that are the dominant products of catechol oligomerization. Therefore, here isolation and characterization of catechol isomeric dimers, obtained by oxidative coupling under the catalysi…

Chemical and spectroscopic characteristics of the wood of Vitis vinifera cv. Sangiovese affected by esca disease.

2009

Chemical and spectroscopic analyses ((13)C cross-polarization-magic angle spinning NMR and attenuated total reflection Fourier transform infrared spectroscopies) were carried out on the wood of Vitis vinifera cv. Sangiovese with brown-red discoloration and black streaks caused by esca disease. The analyses of the brown-red wood revealed the destruction of hemicelluloses and noncrystalline cellulose as well as modifications in the pectic and ligninic wood fractions. The pectic fraction consisted of carbohydrates associated with polyphenols. The lignin fraction exhibited only a few changes in the aromatic systems and a partial demethylation, and it appeared to be associated with condensed phe…

Dissolution mechanism of crystalline cellulose in H3PO4 as assessed by high-field NMR spectroscopy and Fast Field Cycling NMR relaxometry

2009

Many processes have been proposed to produce glucose as a substrate for bacterial fermentation to obtain bioethanol. Among others, cellulose degradation appears as the most convenient way to achieve reliable amounts of glucose units. In fact, cellulose is the most widespread biopolymer, and it is considered also as a renewable resource. Due to extended intra- and interchain hydrogen bonds that provide a very efficient packing structure, however, cellulose is also a very stable polymer, the degradation of which is not easily achievable. In the past decade, researchers enhanced cellulose reactivity by increasing its solubility in many solvents, among which concentrated phosphoric acid (H(3)PO…

A new heuristic algorithm for the analysis of NMRD dispersion curves

Regression analysis of the NMRD dispersion curves obtained by the FFC-NMR relaxometric technique involves several conceptual and practical issues, which must be carefully addressed in order to gain reliable information on the system studied. Indeed, particular caution is needed when the FFC technique is applied to the investigation of complex systems such as polymeric matrixes, porous materials, food samples, and so on. In these cases, and in general whenever a rigorous approach based on a suitable physical modelization of the system is not available, data analysis must be performed by means of a “model–free” approach. Moving forward from previous literature, in the present communication we…

Reconstruction of the environmental evolution of a Sicilian saltmarsh (Italy)

2013

The present study deals with the reconstruction of the environmental evolution of a Trapani saltmarsh (southwestern Sicily, Italy) by combining different analytical approaches such as metal content evaluation, low-field nuclear magnetic resonance (NMR) relaxometry, and benthic foraminifera identification. A 41 cm core was collected in the sediments of a Trapani saltmarsh (southwestern Sicily, Italy) at a water depth of about 50 cm. Different time intervals were recognized, each characterized by peculiar features that testify different environmental conditions. In particular, the bottom layers of the sediment core (41–28 cm) comprised the lowest amount of mud fraction, only some selected met…

Solid state nuclear magnetic resonance spectroscopy as a tool to characterize natural organic matter and soil samples. The basic principles

2007

Basic principles of solid state nuclear magnetic resonance spectroscopy (SS-NMR) are presented here. This paper is not pretending to provide an exhaustive treatment of the basics of SS-NMR. However, it will give an overview of the main applications in the characterization of environmental systems and will describe the problems related to the acquisition of quantitative solid state NMR spectra.

Synthesis and characterization of a novel high luminescent gold-2-mercapto-1-methyl-imidazole complex

2010

Synthesis and characterization of a new gold-2-mercapto-1-methyl imidazole are reported. This new organic material shows an extraordinary fluorescence activity (superfluorescence) up to 220°C with an unusual quantum yield of 0.2. Both fluorescence and NMR spectroscopy were applied to understand the behavior of the gold-2-mercapto-1-methylimidazole complex. Results suggest that the superfluorescence activity can be attributed to the shrinking of the HOMO-LUMO band gap energy following complexation of the organic imidazole system with gold. Copyright © 2010 John Wiley & Sons, Ltd.

Fast field cycling NMR relaxometry as a tool to monitor Parmigiano Reggiano cheese ripening.

2020

Abstract It is widely recognized that the longer the ageing, the more valuable Parmigiano Reggiano (PR) cheese becomes, due to the improvement of its sensorial and nutritional properties. Up to now, the evaluation of PR properties has been performed on samples mainly aged up to 40 months. For this reason, this study was aimed at collecting information about the chemical-physical characteristics of PR cheeses after ageing at 24, 48 and 84 months. The basic analyses on water amount, protein content and volatile organic compounds (VOC) revealed that PR ageing is associated to the decomposition of the organic components into smaller units. This drives water molecules closer to the aforementione…

Changes in Physicochemical Properties of Biochar after Addition to Soil

2022

It is recognized that biochar undergoes changes when it is applied to soils. However, the mechanisms of biochar alterations are not fully understood yet. To this purpose, the present study is designed to investigate the transformations in the soil of two different biochars obtained from pyrolysis of fir-wood pellets. The production of the biochars differed for the dry and wet quenching procedures used to terminate the pyrolysis. Both biochars were applied to clay soil (26% sand, 6% silt, and 68% clay) placed into lysimeters. After water saturation and 15 days of equilibration, seeds of watercress (Lepidium sativum) were cultivated. After a further 7 weeks, the biochars were manually separat…

Measuring hydrological connectivity inside a soil by low field nuclear magnetic resonance relaxometry

2017

Hydrological connectivity inside the soil is related to the spatial patterns inside the soil (i.e., the structural connectivity). This, in turn, is directly associated with the physical and the chemical processes at a molecular level (i.e., the functional connectivity). Nuclear magnetic resonance (NMR) relaxometry can be successfully applied to reveal both structural and functional components of soil hydrological connectivity. In the present study, the low field NMR relaxometry was applied on water suspended soils sampled at the upstream- and downstream-end of three different length plots. Also the sediments collected from the storage tanks at the end of each plot were water suspended and m…

Effect of ramp size and sample spinning speed on CPMAS 13C NMR spectra of soil organic matter

2011

Abstract Cross polarization (CP) magic angle spinning (MAS) 13C NMR spectroscopy is a solid state NMR technique widely applied to study the chemical composition of natural organic matter. In high magnetic fields (>7 T), fast sample spinning is required in order to reduce the influence of spinning sidebands underlying other chemical shift regions. As the spinning speed increases, the Hartmann–Hahn matching profiles break down into a series of narrow matching bands. In order to account for this instability variable amplitude cross polarization techniques (e.g. VACP, ramp-CP) have been developed. In the present study, we experimentally verified the stability of the Hartmann–Hahn condition unde…

Designing biochar properties through the blending of biomass feedstock with metals: Impact on oxyanions adsorption behavior

2018

Metal-blending of biomass prior to pyrolysis is investigated in this work as a tool to modify biochar physico-chemical properties and its behavior as adsorbent. Six different compounds were used for metal-blending: AlCl3, Cu(OH)2, FeSO4, KCl, MgCl2 and Mg(OH)2. Pyrolysis experiments were performed at 400 and 700 °C and the characterization of biochar properties included: elemental composition, thermal stability, surface area and pore size distribution, Zeta potential, redox potential, chemical structure (with nuclear magnetic resonance) and adsorption behavior of arsenate, phosphate and nitrate. Metalblending strongly affected biochars' surface charge and redox potential. Moreover, it incre…

Plant growth improvement mediated by nitrate capture in co-composted biochar

2015

AbstractSoil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2% (w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting (BC…

Effects of ions on water structure: a low-field1HT1NMR relaxometry approach

2014

Aqueous salt solutions play an important role in nature because of their effects on environmental biogeochemical processes and on structural properties of biomolecules. Upon dissolution, salts split in ions that are solvated. Water in hydration shells is subjected to molecular motions that can be monitored by (1)H T1 NMR relaxometry. This technique allowed the evaluation of the nature of the interactions between water and ions via variable temperature experiments. Examination of relaxometry properties of aqueous solutions at variable salt concentrations allowed acknowledgement of the role played by ions in either structuring or destructuring water aggregates. A mathematical model has been a…

Reduced graphene oxide/silver nanoparticles/β-cyclodextrin nanosponges composites with improved photocatalytic activity

2023

Significant activity improvement was achieved by associating graphene oxide-silver composite photocatalysts with cyclodextrin-based nanosponge materials, due to the synergistic effect provided by the supramolecular host abilities of the nanosponge. Three photocatalysts were prepared, fully characterized (FT-IR, ss-NMR, Raman, XRD, SEM, EDX, AFM, ICP, TGA, potentiometric titration), and tested for the oxidative photodegradation of some dyes and phenols, chosen as model organic pollutants. Compared to the unsupported photocatalyst, the nanosponge-based materials showed enhanced performances (being able to carry out the degradation even of dyes which do not react in the presence of the unsuppo…

Thermal transformation of micro-crystalline cellulose in phosphoric acid

2011

Use of crude oil derivatives such as diesel and gasoline is becoming unsuitable due to their detriment to environment and to the increasing worldwide energy demand which is driving crude oil reservoirs towards exhaustion. Replacement of diesel and gasoline with biofuels (i.e. biodiesel and bioethanol, respectively) is very desirable. In fact, biofuels are not only environmentally sustainable, but also potentially inexhaustible due to the large amounts of waste biomasses from which they can be retrieved. In the present study, a model compound (micro-crystalline cellulose) was dissolved in phosphoric acid and converted at 80 °C to glucose, thereby providing the possible substrate for fermenta…

Evaluation of the surface affinity of water in three biochars using fast field cycling NMR relaxometry

2016

Many soil functions depend on the interaction of water with soil. The affinity of water for soils can be altered by applying soil amendments like stone meal, manure, or biochar (a carbonaceous material obtained by pyrolysis of biomasses). In fact, the addition of hydrophobic biochar to soil may increase soil repellency, reduce water-adsorbing capacity, inhibit microbial activity, alter soil filter, buffer, storage, and transformation functions. For this reason, it is of paramount importance to monitor water affinity for biochar surface (also referred to as ‘wettability’) in order to better address its applications in soil systems. In this study, we propose the use of fast field cycling NMR …

Humic Substances: From Supramolecular Aggregation to Fractal Conformation—Is There Time for a New Paradigm?

2023

Natural organic matter, including humic substances (HS), comprises complex secondary structures with no defined covalent chemical bonds and stabilized by inter- and intra-molecular interactions, such as hydrogen bonding, Van der Waal’s forces, and pi-pi interactions. The latest view describes HS aggregates as a hydrogel-like structure comprised by a hydrophobic core of aromatic residues surrounded by polar and amphiphilic molecules akin a self-assembled soft material. A different view is based on the classification of this material as either mass or surface fractals. The former is intended as made by the clustering of macromolecules generating dendritic networks, while the latter have been …

Factors influencing structural heat-induced structural relaxation of dissolved organic matter

2018

Abstract Physical and chemical structure affect properties of dissolved organic matter (DOM). Recent observations revealed that heating and cooling cycles at higher temperature amplitude lead to a change in DOM physical conformation assumingly followed by a slow structural relaxation. In this study, changes at lower temperature amplitudes and their relation to DOM composition were investigated using simultaneous measurements of density and ultrasonic velocity in order to evaluate the adiabatic compressibility, which is sensitive indicator of DOM structural microelasticity. Six fulvic acids (FAs) having various origins were analyzed at concentrations of 0.12, 0.6 and 1.2 g L−1 and at differe…

Spatial patterns of, and environmental controls on, soil properties at a riparianepaddock interface

2012

Abstract Riparian zones are prominent features of agricultural landscapes because they are the last point to intercept nutrients and sediments before they enter water bodies. We investigated the soil properties, nutrient dynamics and vegetation composition at the riparian–agriculture interface. Soil physicochemical and vegetation properties were spatially heterogeneous along the transition from the grazed paddock into the un-grazed and revegetated riparian zone. Soil C stocks varied considerably across the site, with values ranging from 2% in the paddock to 5% in the riparian zone. Using Bayesian model selection, a predictive model for total soil carbon was developed. By including soil mois…

Environmental applications of fast field-cycling NMR relaxometry

2019

Environmental sustainability is the modern scientific-field key word. This is because a novel awareness about environmental safety occurred since the “Rio Declaration on Environment and Development” was produced in 1992. For this reason, new and environmentally sustainable analytical techniques have been (and still are) produced. The main focus of these techniques is not only the use of “green” chemicals (i.e. chemical compounds showing low environmental impact), but also the waste reduction through the simplification of the analytical procedures such as extractions and purifications. In particular, the modern analytical trend is to find procedures which allow investigation of complex syste…

Precise measurement of 1H 90° pulse in solid-state NMR spectroscopy for complex and heterogeneous molecular systems

2007

The 90 degrees pulse calibration is essential in NMR spectroscopy to prevent artefacts in the liquid state or to enhance cross-polarization efficiency in the solid state. We verified pulse-angle (PA) errors due to circuit impedances in solid-state NMR and suggested a possible solution to prevent the inconvenience of PA errors. The classic pulse sequences used to calibrate (1)H 90 degrees pulse lengths by direct detection of protons or by cross-polarization were modified in order to replace single (1)H pulses with (1)H pulse trains. Pulse trains were found to decrease the effect of PA imperfections in the calibration of basic pulses (i.e. 90 degrees and 180 degrees ) for a number of organic …

Dynamics of pistachio oils by proton nuclear magnetic resonance relaxtion dispersion

2011

A number of pistachio oils were selected in order to test the efficacy of nuclear magnetic resonance relaxation dispersion (NMRD) technique in the evaluation of differences among oils (1) obtained from seeds subjected to different thermal desiccation processes, (2) retrieved from seeds belonging to the same cultivar grown in different geographical areas and (3) produced by using seed cultivars sampled in the same geographical region. NMRD measures relaxation rate values which are related to the dynamics of the chemical components of complex food systems. Results not only allowed to relate kinematic viscosity to relaxometry parameters but also were successful in the differentiation among the…

Rilassometria in fase solida di tessuti di una solanacea affine a melanzana a differenti frequenze di Larmor protoniche

2008

SHORT-TERM RESPONSE OF SOIL MICROORGANISMS TO ESSENTIAL OILS WITH ALLELOPATHIC POTENTIAL EXTRACTED FROM MEDITERRANEAN PLANTS

2015

Essential oils (EOs) with allelopathic compounds have been used to reduce or avoid weed germination and growth. The aim of this study was to evaluate the potential phytotoxic effects of EOs extracted from different Mediterranean plants on soil microbial biomass and activity. EOs were extracted from leaves of Eucalyptus camaldulensis Dehnh (EUC); Eriocephalus africanus L. (ERI); Thymus capitatus (L.) Hoffmanns. & Link (TCP); Citrus reticulata Blanco var. ‘Clemenules’ (TAN) and Citrus limon (L.) Osbeck var. ‘Eureka’ (LEM). Each EO was supplied to pots containing 560 g of soil at three different doses (low, medium, high). After 15, 30, 90, 120 days the supply of EOs, soils were destructively a…

Coil homogeneity and the effect of rotor filling on the spectral resolution

2009

Spectral resolution depends upon the length (N) of the transform interval: N=F/ f, where f is the smallest frequency difference which can be distinguished at a given sampling frequency F. f depends on the signal width, which, in turn, is influenced by the relaxation time of the sampled signal. Relaxation time is affected by the external magnetic field and the applied pulse sent to the sample through the transmitter/receiver coil. The pulse length homogeneity throughout this coil is a major factor affecting NMR resolution and also the sensitivity of the measurement. So far, this fact is only considered when small sample amounts are used, where care should be taken to place the sample in the …

Efficiency of biochar for reducing mobility of inorganic contaminants

2013

Anthropogenic activities have produced numerous sites with extensive contamination close to residential areas. Several physicochemical and biological remediation methods exist for remediation of metal contaminated soils and lands, such as soil washing, soil flushing, phytoremediation, and electrokinetics. Biochar (biologically derived charcoal) is produced by pyrolysis of biomasses under low oxygen conditions, and it can be applied for recycling organic waste in soils. The main objectives of the present study were to determine the possible use of biochar from forest ersidues (Populus nigra) in order to achieve a stabilization of inorganic contaminants by adsorption processes. Adsorption of …

Influenza della temperatura di pirolisi e del tempo di residenza sulle proprietà fisico-chimiche del biochar prodotto da pollina

2013

La pollina è tradizionalmente utilizzata in agricoltura come fertilizzante organico grazie al suo alto contenuto in nutrienti immediatamente disponibili per le piante (principalmente azoto, potassio e fosforo). Nonostante i vantaggi apportati alle colture, l’eccessivo uso della pollina come ammendante del suolo può causare gravi problemi ambientali, tra cui rischi per la salute umana e lisciviazione di nitrati o altri inquinanti nelle acquee sotterranee. Per diminuire i rischi legati al suo utilizzo, una soluzione alternativa potrebbe essere il ri-utilizzo energetico della pollina tramite la sua conversione in biochar. Il biochar è una sostanza carboniosa derivante dalla pirolisi di qualsia…

Caratterizzazione di sostanza organica disciolta mediante rilassometria NMR in modalità fast field cycling

2009

EFFECT OF METALS ON THE DYNAMICS OF WATER AT THE BIOCHAR SOLID-LIQUID INTERFACE

2014

Previous studies revealed that water molecules are hooked to biochar surfaces through unconventional hydrogen bonds (De Pasquale et al., 2012; Conte et al., 2013). Next question to answer is how metals can affect water mobility as they are adsorbed on biochar surface. To this aim, an orchard pruning char obtained by pyrolysis at 500°C was treated with solutions of Cu(II), Cr(VI) and Cu(II)+Cr(VI). Two different types of water can be recognized in BC. Namely, a fast relaxing water (T1 = 99 ms) is differentiated by a slow relaxing one (T 1= 233 ms). The former is made by molecules interacting with biochar surface through formation of the unconventional Hbonds previously identified (De Pasqual…

Differenze tra tessuti del frutto di una solanacea affine a melanzana a differenti tempi di maturazione attraverso misure di dinamica molecolare NMR

2008

Caratterizzazione mediante spettroscopia NMR in fase solida di foglie e lettiera di quattro essenze forestali

2008

La velocità di degradazione del materiale vegetale che arriva al suolo dipende dalle caratteristiche chimico-fisiche dei residui che ne influenzano l’appetibilità e, dunque, la facilità con cui i microrganismi li degradano. Molti studi hanno evidenziato come elevate percentuali di lignina e di composti polifenolici possano limitare l’attività dei microrganismi, in quanto poche specie microbiche hanno un apparato enzimatico completo per la degradazione dei suddetti polimeri. Obiettivo del presente lavoro è l’analisi, tramite spettroscopia NMR in fase solida (CPMAS 13C-NMR), della composizione molecolare delle foglie e della relativa lettiera di 4 essenze forestali: Eucaliptus occidentalis En…

Effect of wetting/drying on the conformational arrangement of a heterogeneous organic mixture as assessed by solid state 13C NMR spectroscopy

2008

Polymerization of humic substances catalyzed by iron and manganese porphirins

2005

Spettroscopia 31P-NMR per la caratterizzazione del fosforo nei suoli

2007

Analisi delle interazioni tra sostanze umiche e cationi metallici mediante CPMAS 13C NMR

2007

Thermal degradation of microcrystalline cellulose in concentrated phosphoric acid as assessed by HPLC, high field NMR spectroscopy and low field NMR …

2011

The most common renewable fuel is ethanol. It is a liquid produced by fermentation of glucose which is very abundant in cellulose based material sources. Plants produce about 180 billion tons of cellulose per year globally. For this reason cellulose is the largest organic carbon reservoir on Earth. Cellulose is composed exclusively of glucose units linked via B-1,4 glycosidic bonds. Each D-(+)-glucose unit contains three hydroxyl groups, which can form complex spatial networks of inter- and intra- molecular hydrogen bonds. They are responsible for the high crystallinity and compactness of cellulose, thereby making it very resistant to biological and chemical attack. In the presence of miner…

Distribution of a 13C-labelled hydrophobic tracer over humic fractions of different size and composition

2004

Tridimensional molecular assembly of the major components of extra-virgin olive oils

2009

USE OF BIOCHAR FOR INORGANIC CONTAMINANTS REMEDIATION

2013

Anthropogenic activities alter the natural flow of materials and introduce novel chemicals into the environment thereby causing serious soil and water pollution Indeed, many industries produce aqueous effluents containing toxic substances, especially heavy metals The presence of these contaminants in the environment is a great issue because of their toxicity and bioaccumulation ability which affect human life and the environment Various physicochemical and biological techniques have been used to remove the heavy metals from waste waters, including chemical precipitation, ion exchange, chemical coagulation, electrolytic methods, membrane processes, and adsorption Biochar is a carbonaceous ma…

EVALUMION OF THE CHEMICAL PHYSICAL DIFFERENCES AMONG SICILIAN HONEYS

2009

Discrimination of Phyllosticta Ilicina effectors by advanced HRMAS and CPMAS 13C-NMR techniques and electrolytes leakage assay (ELA)

2007

Interaction between a recombinant prion protein and organo-mineral complexes as evidenced by CPMAS 13C-NMR

2009

Prion proteins (PrP) are the main responsible for Transmissible Spongiform Encephalopathies (TSE). The TSE etiological agent is a misfolded form of the normal cellular prion protein. The amyloidal aggregates accumulated in the brain of infected animals and mainly composed of PrPSc exhibit resistance to protease attack and many conventional inactivating procedures. The prion protein diseases cause an environmental issue because the environment and in particular the soil compartment can be contaminated and then become a potential reservoir and diffuser of TSEs infectivity as a consequence of (i) accidental dispersion from storage plants of meat and bone meal, (ii) incorporation of contaminate…

Caratterizzazione molecolare di frazioni lipidiche ottenute da acidi umici differenti mediante risonanza magnetica nucleare (NMR) e spettrometria di …

2007

EFFECTS ON SEED GERMINATION OF DIFFERENT BIOCHARS FROM INDUSTRIAL THERMOCHEMICAL PROCESSES

2014

Char or biochar is a type of charcoal obtained from gasification/pyrolysis of biomasses. Instead of burning standing biomass from cleared forest, the resource is charred. The result is a highly porous, carbon-rich solid residue, really similar in appearance to the coal produced by natural burning. First considered an industrial waste, in recent years, the interest in this material has grown enormously given its ability to improve physical, chemical, biological and mechanical properties of soils, when used as amendment. However, its effects are highly variable depending onits chemical-physical properties which in turn depend greatly on the starting feedstock. The present study reports about …

DINAMICA DELL’ACQUA SULLA SUPERFICIE DI UN BIOSSIDO DI TITANIO NANOSTRUTTURATO SINTETIZZATO IN LABORATORIO

2013

Un campione biossido di titanio sintetizzato in laboratorio è stato ottenuto mediante idrolisi di TiCl4 in acqua deionizzata (rapporto in volume 1:10) a temperatura ambiente. Dopo 12 h di agitazione la soluzione trasparente è stata portata all’ebollizione per 0.5 h per ottenere la sospensione finale. La sospensione è stata quindi seccata alla temperatura di 50°C per ottenere il catalizzatore in polvere. Successivamente, la polvere così ottenuta è stata lavata e centrifugata diverse volte allo scopo di ridurre fino a valori trascurabili la concentrazione di ioni cloruro nell’acqua di lavaggio. Il catalizzatore così ottenuto è stato denominato HP0.5 (Home Prepared bollito per 0.5 h) [1]. Un g…

Degradazione termica di biomasse lignocellulosiche in acido fosforico

2013

La lignocellulosa è la più abbondante fonte rinnovabile per la produzione di bioetanolo. Sfortunatamente la produzione di biocarburanti liquidi da scarti lignocellulosici presenta molti inconvenienti a causa della compattezza e della complessità di questi materiali, caratteristiche che rendono molto più difficoltosa la loro degradazione enzimatica in zuccheri fermentabili rispetto ad altri biopolimeri come l’amido. Inoltre il costo della produzione di bioetanolo da biomasse lignocellulosiche è ancora molto alto rispetto a quello dei processi industriali che utilizzano come materiale di partenza l’amido. Obiettivo del presente studio è quello di testare su campioni di biomassa lignocellulosi…

Regeneration of cellulose by water addition to phosphoric acid/cellulose mixture

2013

In the last years, phosphoric acid has been increasingly considered as a simple and economic solvent for cellulose pretreatment before its degradation to glucose. Cellulose swells in 71–80% phosphoric acid solutions, whereas at higher H3PO4 concentrations dissolution appears to occur. In addition, it is reported that regenerated cellulose is more easily fermentable to bioethanol. The aim of the present study was to elucidate the mechanism for cellulose regeneration following treatment with phosphoric acid at room temperature. CPMAS 13C NMR spectra revealed a downfield shift of the 13C NMR signals from the regenerated cellulose as compared to the crystalline one. CPMAS 31P NMR spectroscopy s…

Thermal degradation of microcrystalline cellulose in concentrated phosphoric acid

2011

The most common renewable fuel is ethanol. It is a liquid produced by fermentation of glucose which is very abundant in cellulose based materials. Bioethanol is achieved in a two-steps process: 1. hydrolysis of the cellulose included in the ligno-cellulosic materials to fermentable reducing sugars; 2. fermentation of such sugars to ethanol. While the second fermentation step, mediated by yeasts or bacteria, is very well established, the first one must be still assessed for process optimization. Many efforts have been made to identify solvents for cellulose in order to develop methods for the achievement of fermentable glucose. In the presence of mineral acid, cellulose undergoes hydrolysis …

Effect of texture on the dynamics of a water saturated biochar

2014

Biochar is defined as charred organic matter applied to soil in a deliberate manner, with the intent to improve soil properties (Lehmann et al., 2009). Biomass-derived char can be used as energy carrier, as adsorber and as material for the improvement of soil properties. Carbonized organic matter can have different physical and chemical properties depending on the technology used for its production. Moreover char texture influences deeply physical and chemical properties. In this work effect of texture on the dynamics of a water saturated biochar was analyzed by FFC NMR. An industrial biochar derived from gasification of poplar wood was sieved to determine influence of texture on water dynami…

Carbohydrates and aggregation in lowland soils of Nigeria as influenced by organic input

2004

Conformational behaviour of humic substances at different depths along a profile of a Lithosol under loblolly (Pinus taeda) plantation

2009

The conformation of natural organic matter (NOM) plays a key role in many physical and chemical processes including interactions with organic and inorganic pollutants and soil aggregates stability thus directly influencing soil quality. NOM conformation can be studied by solid state NMR spectroscopy with cross polarization and magic angle spinning (CPMAS NMR). In the present study we applied CPMAS 13C NMR spectroscopy on three humic acid fractions (HA) each extracted from a different horizon in a Lithosol profile under Pinus taeda. Results showed that the most superficial HA was also the most aliphatic in character. Amount of aromatic moieties and hydrophilic HA constituents increased along…

Interactions between a humic acid and a paramagnetic cation as assessed by CPMAS 13C NMR spectroscopy

2009

Humic substances (HSs) are natural organic materials playing a very important role in environment due to their ability in interacting with organic and inorganic compounds. From the one side, HSs can reduce the toxic effects of organic and inorganic contaminants, while, from the other side, they can enhance availability of nutrients, such as cations, to living organisms including plants. For this reason it is very crucial to understand the mechanisms of the interactions between humic substances and the environmentally relevant chemical components. In the present work, we have investigated the mechanisms of interaction between a HS and iron (III) by using cross polarization magic angle spinni…

Rapid measurement of 1H 90° pulse in the solid state NMR via cross polarization

2006

Low field NMR spectroscopy for quality evaluation of natural organic matter

2009

Confronto NMR tra diverse forme di cellulosa in materiali cartacei da raccolta differenziata

2008

Preliminary studies on treated waterlogged wood by low field NMR spectroscopy

2009

Uso della spettroscopia di risonanza magnetica nucleare 1H-HRMAS e della gas cromatografia per la differenziazione di Solanacee affini a melanzana (S…

2008

New understanding of cross-polarization dynamics in amorphous and heterogeneous natural organic substances

2008

Supramolecular organization of triglycerides in extra-virgin olive oils as assessed by high and low field NMR spectroscopies

2009

Characterization of the volatile components relased from natuaral organic substances

2008

Effect of kinematic viscosity over the dynamic properties of an extra-virgin olive oil

2011

Previous studies 1,2 have shown that kinematic viscosity values of food oils depend on the presence of added solvents and on the nature of the oil under investigation (e.g., geographical origin and treatments prior to oil production). However, to the best of our knowledge, only one paper 3 dealt with the correlation between viscosity values and relaxation times of simple pure alkyl compounds. Up to now, no papers have been found in literature dealing with viscosity of complex mixtures and their relaxometric properties. In this study, we intended to investigate the effect of kinematic viscosity over the dynamic properties of an extra-virgin olive oil which is known as a very complex mixture …

Solid state NMR spectroscopy in the evaluation of the conformational changes of humic substances as affected by thermal variations

2009

Valutazione del grado di stagionatura del parmigiano mediante misure di rilassometria NMR a ciclo di campo

2010

EVALUATION OF INORGANIC CONTAMINANT REMOVAL FROM AQUEOUS SOLUTIONS USING PYROLIZED CHICKEN MANURE, CONIFER AND POPLAR WOOD AS ADSORBENT

2014

Anthropogenic activities alter the natural flow of materials and introduce novel chemicals into the environment thereby causing serious soil and water pollution. Indeed, many industries produce aqueous effluents containing toxic substances, especially heavymetals. The presence of these contaminants in the environment is a great issue because of their toxicityand bioaccumulation ability which affect human life and the environment. Various physicochemical and biological techniques have been used to remove the heavy metals from waste waters, including chemical precipitation, ion exchange, chemical coagulation, electrolytic methods, membrane processes, and adsorption. Biochar is a carbonaceous …

Biochar Effects on Ce Leaching and Plant Uptake in Lepidium sativum L. Grown on a Ceria Nanoparticle Spiked Soil

2023

Effects of ions on water structure: a low-field (1) H T1 NMR relaxometry approach

2014

Aqueous salt solutions play an important role in nature because of their effects on environmental biogeochemical processes and on structural properties of biomolecules. Upon dissolution, salts split in ions that are solvated. Water in hydration shells is subjected to molecular motions that can be monitored by (1) H T1 NMR relaxometry. This technique allowed the evaluation of the nature of the interactions between water and ions via variable temperature experiments. Examination of relaxometry properties of aqueous solutions at variable salt concentrations allowed acknowledgement of the role played by ions in either structuring or destructuring water aggregates. A mathematical model has been …

Assessing the influence of different biochar fractions on soil structure and soil water retention: laboratory investigation on a Sicilian soil

2012

Solid state nuclear magnetic resonance spectroscopy in the evaluation of soil organic matter changes following thermal variations

2009

Soil organic matter (SOM) is an ubiquitous, complex material which is produced by the degradation of plant tissues and animal bodies. It is the major indicator of soil quality since it is directly involved in the maintenance of soil fertility, prevention of erosion and desert encroachment and provision of suitable environment for biological activity. Organic matter is an important driving force in environmental global change as it acts as both a source and sink of atmospheric carbon. However, SOM is subjected to rapid changes due to environmental transformations such as massive deforestations, fires, intensive land uses, temperature increases and so on. In the present work, a characterizati…

Caratterizzazione della componente volatile rilasciata da sostanza organica naturale di suoli vulcanici

2008

Il suolo è una matrice caratterizzata da notevole complessità chimico-fisica. Tra le varie componenti, la sostanza organica naturale (NOM) gioca un ruolo fondamentale nelle interazioni con contaminanti di natura organica ed inorganica. La NOM è attualmente considerata una associazione supramolecolare di sistemi organici con un peso molecolare non superiore a 1000-2000 Da. La sua caratterizzazione è tradizionalmente effettuata mediante l’ausilio di tecniche cromatografiche e spettroscopiche. La verifica dell’allontanamento di molecole a basso peso molecolare all’aumento della temperatura, nell’intervallo 40-100 °C, è stata condotta con tecniche di microestrazione in fase solida in spazio di …

BIOCHAR SURFACE PROPERTIES THROUGH APPLICATION OF AN INNOVATIVE NMR TECHNIQUE: FAST FIELD CYCLING RELAXOMETRY

2013

Biochar is a carbonaceous material obtained by pyrolysis of biomass feedstocks. It is applied to soils in order to improve fertility and mitigate greenhouse-gases emissions. In fact, from the one hand, biochar changes physical-chemical soil properties, thereby affecting soil fertility. From the other hand, biochar is resistant to chemical and biochemical degradation. For this reason, its use allows carbon sequestration in soils and consequent reduction of carbon dioxide to the atmosphere. Here, dynamics of water at the liquid-solid interface of water saturated biochars is discussed. Results revealed that water dynamics is affected by the nature of biochar parent biomasses. Moreover, biochar…

Fast field Cycling NMR for quality characterization of typical sicilian honeys.

2009

Proton NMR relaxometry with fast field cycling (FFC-NMR) setup is developing as a very promising tool for the characterization of agro-food matrices. In fact, some papers have been published reporting on differences among balsamic vinegars, porous properties of oil-water emulsions and quality of meat-products. In the present study, quality of some typical Sicilian honey samples has been evaluated by traditional wet-chemical analyses and FFC-NMR. Nine wet-chemical parameters have been measured such as water content, pH, acidity (free, lactonic and total acidity), fructose, glucose, saccharose, electrical conductivity, diastase activity and colour. Results showed that 84% of the samples were …