The efforts have been made to review phyllosilicate derived (clay-based) heterogeneous catalysts for biodiesel production via lignocellulose derived feedstocks. These catalysts have many practical and potential applications in green catalysis. Phyllosilicate derived heterogeneous catalysts (modified via any of these approaches like acid activated clays, ion exchanged clays and layered double hydroxides) exhibits excellent catalytic activity for producing cost effective and high yield biodiesel. The combination of different protocols (intercalated catalysts, ion exchanged catalysts, acidic activated clay catalysts, clay-supported catalysts, composites and hybrids, pillared interlayer clay catalysts, and hierarchically structured catalysts) was implemented so as to achieve the synergetic effects (acidic-basic) in resultant material (catalyst) for efficient conversion of lignocellulose derived feedstock (non-edible oils) to biodiesel. Utilisation of these Phyllosilicate derived catalysts will pave path for future researchers to investigate the cost-effective, accessible and improved approaches in synthesising novel catalysts that could be used for converting lignocellulosic biomass to eco-friendly biodiesel.

• MeSH
• Biomass MeSH
• Biofuels * MeSH
• Esterification MeSH
• Catalysis MeSH
• Lignin MeSH
• Plant Oils * MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

The importance of studies on photoactive zinc oxide nanoparticles (ZnO NPs) increases with increasing environmental pollution. Since the ZnO NPs (and NPs in general) also pose an environmental risk, and since an understanding of the risk is still not sufficient, it is important to prevent their spread into the environment. Anchoring on phyllosilicate particles of micrometric size is considered to be a useful way to address this problem, however, so far mainly on the basis of leaching tests in pure water. In the present study, the phytotoxicity of kaolinite/ZnO NP (10, 30, and 50 wt.%) nanocomposites in concentrations 10, 100, and 1000 mg/dm3 tested on white mustard (Sinapis alba) seedlings was found to be higher (relative lengths of roots are ~ 1.4 times lower) compared with seedlings treated with pristine ZnO NPs. The amount of Zn accumulated from the nanocomposites in white mustard tissues was ~ 2 times higher than can be expected based on the ZnO content in the nanocomposites compared with the ZnO content (100 wt.%) in pristine ZnO NPs. For the false fox-sedge (Carex otrubae) plants, the amount of Zn accumulated in roots and leaves was ~ 2.25 times higher and ~ 2.85 times higher, respectively, compared with that of the pristine ZnO NPs (with respect to the ZnO content). Increased phytotoxicity of the nanocomposites and higher uptake of Zn by plants from the nanocomposites in comparison with pristine ZnO NPs suggest that the immobilization of ZnO NPs on the kaolinite does not reduce the environmental risk.

• MeSH
• Kaolin MeSH
• Plant Roots MeSH
• Plant Leaves MeSH
• Nanoparticles toxicity   MeSH
• Nanocomposites toxicity   MeSH
• Zinc Oxide toxicity   MeSH
• Plants drug effects   MeSH
• Seedlings MeSH
• Publication type
• Journal Article MeSH

We studied arid desert soils from Namibia (Rosh Pinah) that were contaminated with up to 7 mg kg-1 of thallium (Tl) via dust emitted from a local flotation tailing dam. Chemical extractions of waste and soil materials indicated that most of the Tl is strongly bound, in accordance with X-ray diffraction and X-ray absorption spectroscopy data that point to the predominant association of Tl with metal sulfides and phyllosilicates. The isotope fractionation factor ε205Tl of the soil samples (from -0.4 to +3.8) shows a positive linear relationship (R2 = 0.62) with 1/Tl, indicative for the mixing of two major Tl pools, presumably anthropogenic Tl and geogenic Tl. The ε205Tl value for the topmost soil samples (∼+3) closely matches the ε205Tl value for post-flotation waste particles with a diameter of <0.05 mm, whereas the bulk flotation waste exhibits a significantly larger ε205Tl value (∼+6). These variations are in accordance with predominant atmospheric transfer of Tl from the tailings to the adjacent soils via fine (dust) particles. The identified minimal Tl alteration in soils indicates that only a small part of the Tl could be potentially released and passively enter the vegetation, local population and/or food chain in the long term. From this viewpoint, Tl does not represent such an important environmental concern as other (abundant) contaminants at the locality. Furthermore, there could be a relevance for other alkaline desert soils, including those where Tl pollution plays a major role.

• MeSH
• Isotopes MeSH
• Soil Pollutants analysis   MeSH
• Environmental Monitoring methods   MeSH
• Food Chain MeSH
• Desert Climate MeSH
• Soil chemistry   MeSH
• Thallium analysis   MeSH
• Environmental Pollution MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Namibia MeSH

We report a facile methodology for the synthesis of inorganic-organic hydrogels based on integrative assembly of aminopropyl magnesium phyllosilicate (aminoclay) and sodium salt of hyaluronic acid. The viscoelastic materials produced by electrostatic interactions and crosslinking of hyaluronan in the presence of exfoliated synthetic organoclay results in the formation of gel-like behavior retaining a high amount of water. This was confirmed by a rheological study revealing significant dominance of the elastic response over the entire deformation frequency range used. The mechanical strength of the aminoclay-hyaluronan hydrogels was found to be higher than that for related materials based on poly(vinylpyrrolidone)-aminoclay hydrogels.

• MeSH
• Biocompatible Materials chemical synthesis   chemistry   MeSH
• Hydrogels chemical synthesis   chemistry   MeSH
• Hyaluronic Acid chemical synthesis   chemistry   MeSH
• Nanocomposites chemistry   MeSH
• Rheology MeSH
• Aluminum Silicates chemical synthesis   chemistry   MeSH
• Water chemistry   MeSH
• Publication type
• Journal Article MeSH

The adhesion of TiO(2) (anatase structure) nanoparticles to kaolinite substrate was investigated using molecular modeling. Universal force field computation, density function theory computation, and a combination of both two approaches were used. This study enabled the adhesion energy for the TiO(2)/kaolinite nanocomposite to be estimated, and revealed the preferred orientation of the TiO(2) nanoparticles on the kaolinite substrate. The results of all three levels of computation were compared in order to show that the accuracy of universal force field computations is sufficient in this context. The role of nanoparticle size and the importance of the nanoparticle-substrate bonding contribution are presented here and discussed. A comparison of the molecular modeling results with scanning electron microscopy observations showed that the results of the modeling were consistent with the experimental data, and that this approach can be used to help characterize nanocomposites of the nanoparticle/phyllosilicate substrate type.

• MeSH
• Kaolin chemistry   MeSH
• Crystallography MeSH
• Quantum Theory MeSH
• Molecular Conformation MeSH
• Models, Molecular MeSH
• Nanoparticles chemistry   ultrastructure   MeSH
• Nanocomposites chemistry   ultrastructure   MeSH
• Computer Simulation MeSH
• Surface Properties MeSH
• Thermodynamics MeSH
• Titanium chemistry   MeSH
• Particle Size MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Leachates collected at two (active and closed) municipal solid waste (MSW) landfills were examined for colloids and particles by transmission electron microscopy, energy dispersive spectrometry, selected area electron diffraction and for the chemical compositions of the filtrates after the filtration to 0.1 µm and ultrafiltration to 1 kDa (~ 1 nm). Six groups of colloids/particles in the range 5 nm to 5 µm were determined (in decreasing order of abundance): carbonates, phyllosilicates (clay minerals and micas), quartz, Fe-oxides, organics and others (salts, phosphates). Inorganic colloids/particles in leachates from the active landfill predominantly consist of calcite (CaCO(3)) and minor clay minerals and quartz (SiO(2)). The colloids/particles in the leachates from the closed landfill consist of all the observed groups with dominant phyllosilicates. Whereas calcite, Fe-oxides and phosphates can precipitate directly from the leachates, phyllosilicates and quartz are more probably either derived from the waste or formed by erosion of the geological environment of the landfill. Low amounts of organic colloids/particles were observed, indicating the predominance of organic molecules in the 'truly dissolved' fraction (fulvic compounds). Especially newly formed calcite colloids forming particles of 500 nm and stacking in larger aggregates can bind trace inorganic contaminants (metals/metalloids) and immobilize them in landfill environments.

• MeSH
• Colloids analysis   MeSH
• Refuse Disposal MeSH
• Microscopy, Electron, Transmission methods   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• MeSH
• Bentonite toxicity   MeSH
• Risk Assessment MeSH
• Kaolin toxicity   MeSH
• Aluminum Silicates toxicity   MeSH
• Environmental Exposure MeSH

• Conspectus
• Farmacie. Farmakologie
• NML Fields
• toxikologie
• hygiena
• NML Publication type
• publikace WHO