The surface characteristics of an aluminium alloy treated with a commercial chromate pretreatment have been studied by SAM, EDX and XPS. XPS indicates that the chromium is present in the conversion coating as both Cr(III) and Cr(VI) species, and that other components are present at the conversion coating surface, some in a reduced form. The deposition of the chromate layer is compromised by the...

In the title compound, tetra-kis[μ(3)-(2-pyrid-yl)methano-lato]tetra-kis[bromido(methanol)cobalt(III)] tetra-bromide 2-(hydroxy-meth-yl)pyridine tetra-solvate dihydrate, [Co(4)Br(4)(C(6)H(6)NO)(4)(CH(3)OH)(4)]Br(4)·4C(6)H(7)NO(4)·2H(2)O, the cation comprises a [Co(4)O(4)] cubane-type core ( symmetry). The four Co(III) ions and bridging O atoms from four (2-pyrid-yl)methano-late anions are locat...

A a Abstract. The evaluation of the effect of ginger on the modulation of toxic effects induced by chromate is the objective of our study. 50 male rats Albinos wistar were divided to five groups as follow: group I (T) is served as control, received a mineral water by gavage (per os); group II (G) received an experimental diet with 2% of ginger; group III (Cr) received an oral dose of potassium ...

Three aqueous oxidants, Hydrogen peroxide, Sodium Hypochlorite and Calcium Hypochlorite were employed independently in oxidizing Chromium (III) containing tannery wastewaters to soluble chromate (CrO42-) under alkaline conditions. The amount of chromate recovered was determined via spectrophotometry. Hydrogen peroxide was potentially a suitable oxidant as it could recover chromate (CrO42-) up t...

The calcium aluminate hydrate AFm and AFt phases formed upon hydration of Portland cement have an important role in the stabilization solidification hazardous chromate ions hardened cement. monochromate (Ca4[Al(OH)6]2(CrO4)·12H2O), hemichromate (Ca4[Al(OH)6]2(CrO4)0.5(OH)·12H2O) chromate-containing phase, Ca6[Al(OH)6]2-(CrO4)3·24H2O, were synthesized investigated by 1H, 27Al, 53Cr MAS NMR spect...

Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COP...

In the title hydrated mol-ecular salt, (C3H5N2)[Cr(C2O4)2(H2O)2]·2H2O, the complete cation is generated by a crystallographic twofold rotation axis, with one C atom lying on the rotation axis. The complete anion is generated by crystallographic inversion symmetry (Cr(III) site symmetry -1), to generate a slightly distorted CrO6 octa-hedron with trans water mol-ecules and chelating oxalate diani...

Resistance of the indigenous strains P. jadinii M9 and P. anomala M10, to high Cr(6+) concentrations and their ability to reduce chromium in culture medium was studied. The isolates were able to tolerate chromium concentrations up to 104 μg mL(-1). Growth and reduction of Cr(6+) were dependent on incubation temperature, agitation, Cr(6+) concentration, and pH. Thus, in both studied strains the ...

Large-scale industrial use of chromium(VI) has resulted in widespread contamination with carcinogenic chromium(VI). The abilities of microorganisms to survive in these environments and to detoxify chromate require the presence of specific resistance systems. Here we report identification of the transposon-located (TnOtChr) chromate resistance genes from the highly tolerant strain Ochrobactrum t...