abstract siderophores are of important factors influencing bioavailability and fate of heavy metals in the arid and semi-arid soils. they are low molecular weight organic ligands excreted by aerobic soil microorganisms and some plants roots to acquire fe. siderophores may also complex other metals such as pb .the main objective of this study was to investigate the effects of dfob-siderophore on...

Reactions of organic molecules on Montmorillonite clay mineral have been investigated from various aspects. These include catalytic reactions for organic synthesis, chemical evolution, the mechanism of humus-formation, and environmental problems. Catalysis by clay minerals has attracted much interest recently, and many reports including the catalysis by synthetic or modified clays have been pub...

phenolic resins have been widely used for selective high technology applications due to their excellent ablative properties, structural integrity and thermal stability that make them appropriate for thermal insulation materials, wood products industry, coatings, moulding compounds and composite materials. polymer layered silicate nanocomposites based on montmorillonite (mmt) have attracted a gr...

Locations of Cu2+ ion in Cu(2+)-adsorbed montmorillonite have been studied by electron paramagnetic resonance (EPR), supplemented by X-ray diffraction (XRD) and differential thermal analysis (DTA). In the EPR spectra of Cu(2+)-adsorbed montmorillonite, three signals, corresponding to Cu2+ ion, have been simultaneously recorded. Some Cu2+ ions seemed to replace the original interlayer metal cati...

Control of Johne's disease, caused by Mycobacterium avium subsp. paratuberculosis, has been difficult because of a lack of an effective vaccine. To address this problem we used targeted gene disruption to develop candidate mutants with impaired capacity to survive ex vivo and in vivo to test as a vaccine. We selected relA and pknG, genes known to be important virulence factors in Mycobacterium ...

REE (rare earth element) distribution coefficients (Kd) between the aqueous phase and montmorillonite surface were obtained to investigate the relation between the REE distribution patterns and the species of REE sorbed on the solid-water interface. It was shown that the features in the REE patterns, such as the slope of the REE patterns, the tetrad effect, and the Y/Ho ratio, were closely rela...

Amorphous hydrous manganese oxide (HMO) is an important mineral in soils and sediments influencing the mobility and bioavailability of metal contaminants. In this study, nickel and lead sorption to discrete HMO and HMO-coated montmorillonite was investigated mechanistically. The effect of pH and concentration revealed that when normalized to the mass of oxide present, the HMO-coated montmorillo...