Ponceau 6R dye decoloration and chromate reduction simultaneously in acid medium

Chromate reduction in cement using ferrous sulfates

The decoloration and mineralization of azo dye C.I. Acid Red 14 by sonochemical process: rate improvement via Fenton's reactions.

The degradation of azo dye C.I. Acid Red 14 (AR14) was investigated using cast iron in the absence and presence of low frequency ultrasound (59 kHz). The effects of pH, amount of cast iron ([Fe](0)) and initial concentration of AR14 ([dye](0)) on the degradation of AR14 by cast iron combined with low frequency ultrasound had been assessed. The degradation followed the first-order kinetics model...

Mechanism of chromate reduction by the Escherichia coli protein, NfsA, and the role of different chromate reductases in minimizing oxidative stress during chromate reduction.

Chromate [Cr(VI)] is a serious environmental pollutant, which is amenable to bacterial bioremediation. NfsA, the major oxygen-insensitive nitroreductase of Escherichia coli, is a flavoprotein that is able to reduce chromate to less soluble and less toxic Cr(III). We show that this process involves single-electron transfer, giving rise to a flavin semiquinone form of NfsA and Cr(V) as intermedia...

Chromate Reduction by Hydroxycarbonate Green Rust

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...

ChrASO, the chromate efflux pump of Shewanella oneidensis, improves chromate survival and reduction

The chromate efflux pump encoding gene chrASO was identified on the chromosome of Shewanella oneidensis MR1. Although chrASO is expressed without chromate, its expression level increases when Cr(VI) is added. When deleted, the resulting mutant ΔchrASO exhibits a chromate sensitive phenotype compared to that of the wild-type strain. Interestingly, heterologous expression of chrASO in E. coli con...