Search results for "CPMAS 13C NMR"
showing 6 items of 6 documents
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…
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…
CHARACTERIZATION OF CHEMICAL AND PHYSICAL PROPERTIES OF BIOCHAR FOR ENERGY PURPOSES AND ENVIRONMENTAL RESTORATION
2014
Biochar production processes as well as its various applications provide numerous benefits to both environment and economy (Lehmann et al., 2006; Basu, 2010). However, understanding the physicochemical structure of this valuable product has to be improved in order to be able to obtain the aforementioned benefits and to avoid environmental costs. In this study, chicken or poultry manure (PM) was chosen as feedstock for biochar preparation. This biomass is traditionally used by farmers as an effective organic fertilizer (Chan et al., 2008). Indeed, it is considered a valuable source for readily available plant nutrients, such as N, P, K and other micronutrients (Huang et al., 2011). Notwithst…
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…
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…
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…