0000000000324159
AUTHOR
Lorenzo Sanjuan-navarro
New silica based adsorbent material from rice straw and its in-flow application to nitrate reduction in waters: Process sustainability and scale-up possibilities.
Abstract This paper shows a particular example to move to a sustainable circular economical process from valorization of rice straw ashes by developing a green synthesis for obtaining a useful sub-product. This strategy can palliate negative effects of the agriculture waste practices on the environment and also the obtained silica reduced nitrate content in waters. It is demonstrated that the silica synthesis developed at lab was scalable more than a hundred times with good results. Adsorption studies of nitrate in standards and real well waters at lab scale and scaling-up provided similar results. Adsorption values near to 15 mg/g for nitrate standards and 8.5 mg/g for well water were obta…
Characterization and Quantitation of Carbon Black Nanomaterials in Polymeric and Biological Aqueous Dispersants by Asymmetrical Flow Field Flow Fractionation
Characterization of carbon black (CB) nanomaterials is required in industrial and research areas. Hence, in this study, asymmetrical flow field flow fractionation coupled to UV–vis and DLS detectors in series (AF4-UV–vis-DLS) was studied to evaluate the CB dispersion behavior in polymeric and biological dispersants, given the relevance of these media in practical applications. Under the experimental conditions, the results indicated that polymeric and biological dispersions showed size distributions with hydrodynamic diameters of 404 and 175 nm, respectively, for a particle core diameter of 40 nm. The polymeric dispersant provided lower stability as a function of time than that achieved by …
Quantitative study of the capture of silver nanoparticles by several kinds of soils
The capacity of different soils to capture silver nanoparticles (AgNPs) by measuring changes of an AgNP intrinsic property such as the plasmon for the first time, was studied. In-tube solid-phase microextraction (IT-SPME) coupled on-line to capillary liquid chromatography (CapLC) with diode array detection (DAD) was employed for measuring the interactions between soil and in-contact AgNP dispersions. Its achieved LOD 9 pM assures quantitative retention measurements and selectivity for soil lixiviation was suitable. Electronic microscopy was employed for corroborating the entrapped Ag into the soils. Capture % of AgNPs was calculated in compost (>99%), mountain (>99%), orchard (15±1%) and ur…
Aqueous Dilution of Noble NPs Bulk Dispersions: Modeling Instability due to Dissolution by AF4 and Stablishing Considerations for Plasmonic Assays
Among different nanomaterials, gold and silver nanoparticles (AuNPs and AgNPs) have become useful tools for a wide variety of applications in general, and particularly for plasmonic assays. Particle size and stability analysis are key elements for their practical applications since the NPs properties depend on these parameters. Hence, in the present work, asymmetrical flow field flow fractionation (AF4) coupled to UV-Vis and dynamic light scattering (DLS) detectors in series, has been evaluated for stability studies of citrate-capped AuNPs and AgNPs aqueous dispersions. First, experimental parameters, such as mobile phase or cross-flow rate were optimized. Sodium azide to pH 7 for AuNPs and…
In-tube solid phase microextraction coupled to miniaturized liquid chromatography for both, noble metal nanoparticle assessment and sensitive plasmonic assay development.
Abstract Colorimetric localized surface plasmon resonance (LSPR) as analytical response is applied for a wide number of chemical sensors and biosensors. However, the dependence of different factors, such as size distribution of nanoparticles (NPs), shape, dielectric environment, inter-particle distance and matrix, among others, can provide non-reliable results by UV–vis spectrometry in complex matrices if NP assessment is not carried out, particularly at low levels of analyte concentrations. Miniaturized liquid chromatography, capillary (CapLC) and nano (NanoLC), coupled on line with in-tube solid phase microextraction (IT-SPME) is proposed for the first time for both, controlling suitabili…
Study of the Stability of Citrate Capped AgNPs in Several Environmental Water Matrices by Asymmetrical Flow Field Flow Fractionation
Asymmetrical flow field-flow fractionation (AF4) coupled to UV-Vis and dynamic light scattering (DLS) detectors in series, was tested for stability studies of dispersions of citrate-capped silver nanoparticles (AgNPs) in several water matrices. The main goal is to provide knowledge to understand their possible behavior in the environment for short times since mixturing (up to 180 min). Ultrapure (UPW), bottled (BW1, BW2), tap (TW), transitional (TrW) and sea water (SW) matrices were assayed. Observations were compatible with the aggregation of AgNPs, a change in the plasmon band and a size growth with time were done. Fractograms showed different evolution fingerprints in the function of the…
Reduction of Nitrates in Waste Water through the Valorization of Rice Straw: LIFE LIBERNITRATE Project
An improved and more sustainable waste management system is required for successful development of technologies based on renewable sources. Rice straw is submitted to controlled combustion reactions and the produced ashes are chemically treated to produce silica. After a chemical activation step, the activated silica shows potential as an adsorbent agent and will be used to remove the excess of nitrates in groundwater and wells in the area of Alginet (Valencia, Spain), selected as a vulnerable zone within the Nitrates Directive. The demonstration activity aims to have a local impact on municipalities of 200 inhabitants or fewer, decreasing from current nitrate concentrations close to 50 mg/…