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 co...

The hydrothermal reaction of M(NO(3))(2).4H(2)O (M = Zn and Cd) with benzene-1,4-dicarboxylic acid (H(2)bdc) or benzene-1,3-dicarboxylic acid (H(2)ip) and 1,2-bis(1,2,4-triazol-4-yl)ethane (btre) produced the mixed-ligand coordination polymers (MOFs) {[Zn(2)(micro(2)-bdc)(2)(micro(4)-btre)]} (), {[Cd(2)(micro(4)-bdc)(micro(4)-btre)(2)](NO(3))(2).H(2)O} and {[Zn(2)(micro(3)-ip)(2)(micro(2)-btre)...

To investigate chemical and color changes of the polymeric constituents of black locust (Robinia pseudoacacia) wood during heat treatment, extractive-free wood flour was conditioned to 30% initial moisture content (MC) and heated for 24 h at 120 °C in either an oxygen or nitrogen atmosphere. The color change was measured using the CIELAB color system. Chemical changes of the wood components wer...

The interactions of alkali fluorides with D-xylose have been studied by X-ray diffraction (XRD), infrared spectroscopy (IR), nuclear magnetic resonance (NMR, 1H and 13C) and atomic absorption spectrophotometry. KF and CsF form complexes with D-xylose in a 1:1 molar ratio. These complexes can be obtained by solid state milling the reactants in an agate mortar or from methanolic solutions of the ...

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 ...

The molecular composition of water-soluble lignins isolated from four non-food bioenergy crops (cardoon CAR, eucalyptus EUC, and two black poplars RIP and LIM) was characterized in detail, and their potential bioactivity towards maize germination and early growth evaluated. Lignins were found to not affect seed germination rates, but stimulated the maize seedling development, though to a differ...

Chemical reactions (hydrolysis, oxidation, reduction, methylation, alkyl compounds detachment) were applied to modify the structure of humic substances (HS) isolated from vermicompost. Structural and conformational changes of these humic derivatives were assessed by elemental analyses, size exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance ((13)C CPMAS-NMR), and diffusion...

ABSTRACT Forest fires incorporate pyrogenic organic matter into the soil, affecting characteristics of soil (SOM) due to its high aromaticity, increasing renewal time. However, factors that control concentration and chemical composition structure are still little known. fragments dispersed in a savanna matrix northern Brazilian Amazon frequently impacted by fires, which can affect SOM within fr...