Microbial bio-reduction to Cr(III) is a promising strategy for detoxification of chromate, a prevalent anthropogenic pollutant. We propose that this activity can be enhanced in bacteria through engineering of soluble enzymes, such as NfsA, the model Class II chromate reductase of Escherichia coli. We show here that nfsA is induced by chromate, and that it reduces this compound by a “semi-tight”...

The European Union has banned chromium(VI) compounds in electrical and electronic equipment (EEE), such as chromate conversion coating films. Chromium(III) compounds are not banned. Using Raman spectroscopy without any preparation, we distinguished chromium(VI) oxide from chromium(III) oxide and chromium(III) hydroxide in chromate conversion coating films. Raman bands of chromium(VI) oxide were...

The partial loss of crystallization water molecules in the gadolinium(III)-nickel(II) dithiooxalate dodecahydrate [Gd2Ni3(dto)6(H2O)10]·12H2O (1) to yield dihydrate derivative [Gd2Ni3(dto)6(H2O)10]·2H2O (2) provokes significant and reversible changes spin relaxation dynamics. This unique single-crystal-to-single-crystal transformation emerges as a new route toward solvatoswitchable single-molec...

A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter(-1) and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal p...

The structures of the 1:1 proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with 4-nitrophthalic acid [4-carbamoylpiperidinium 2-carboxy-4-nitrobenzoate, C(6)H(13)N(2)O(8)(+)·C(8)H(4)O(6)(-), (I)], 4,5-dichlorophthalic acid [4-carbamoylpiperidinium 2-carboxy-4,5-dichlorobenzoate, C(6)H(13)N(2)O(8)(+)·C(8)H(3)Cl(2)O(4)(-), (II)] and 5-nitroisophthalic acid [4-carbamoylpiper...

The construction and performance characteristics of a novel chromate ion-selective membrane sensor are described and used for determining chromium(III) and chromium(VI) ions. The sensor is based on the use of a rhodamine-B chromate ion-associate complex as an electroactive material in a poly(vinyl chloride) membrane plasticized with o-nitrophenyloctyl ether as a solvent mediator. In a phosphate...

Key words: mineral/water interface, reduced Fe minerals, natural attenuation To address the potential for abiotic natural attenuation of chromate, we have studied the kinetics and mechanism of chromate removal in the presence of hydroxycarbonate green rust. The kinetics of chromate removal were studied in batch systems to evaluate the effect of green rust surface area and pH. The rate of chroma...