Chromium (VI) (Cr(VI)) contamination of soil and groundwater is considered a major environmental concern. Bioreduction of Cr(VI) to chromium (III) (Cr(III)) can be considered an effective technology in remediating Cr(VI) contaminated sites. Among the Cr(VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) is relatively effective. Reduction of Cr(VI) by MR-1 is defined by the dual-enzyme kin...

Treatment of a tetrahydrofuran solution of CrCl2(thf) with Na(hfac), hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate, followed by crystallization from diethyl ether, affords the six-coordinate chromium(II) complex Cr(hfac)2(thf)2. The crystal structures of Cr(hfac)2(thf)2 and the chromium(III) complex Cr(hfac)3 have been determined by single-crystal X-ray diffraction. Cr(hfac)2(thf)2 adopts a tran...

Reaction of chromium(VI) with one equivalent of ascorbate was studied by electron paramagnetic resonance spectroscopy in the presence of 0.10 M 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) at room temperature in 0.10 M (N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid]) (HEPES) and 0.05 M tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) buffers (pH 7.0 room temperature). Chromium(V), a...

High levels of hexavalent chromium (Cr(VI)) in groundwater are typically attributed to anthropogenic sources. However, scientific reports over the last decade have demonstrated that relatively high levels of Cr(VI) in groundwater may also be due to natural processes. Cr(VI) is among the most significant groundwater contaminants, since it is a potential carcinogenic compound that is commonly fou...

background: the degree to which the amount of aningested nutrient is absorbed and available to the body is calledbioavailability. objectives: relative effectiveness of herbalmethionine (h-met®) compared to dl-methionine (dl-met)was investigated in this experiment. methods: exponentialregression analysis was used to determine bioefficacy of h-met®based on body weight gain, feed intake and feed c...

One factor limiting solid oxide fuel cell (SOFC) performance is the degradation of chromium containing, ferritic stainless steel, interconnects during operation. When chromium-containing steels are used as interconnect materials a chromium oxide layer forms on the surface. Under SOFC operating conditions (Cathode gas 800oC and 2.5-3.1% H2O) chromium ions are vaporized by the cathode gas and red...

This review summarizes the results of 15 controlled studies supplementing defined Cr(III) com pounds to subjects with impaired glucose tolerance. Three of these (3-4 /*mol Cr/d for >2 mo) produced no beneficial effects: serum glucose, insulin and lipid con centrations remained unchanged. The remaining 12 in terventions improved the efficiency of insulin or the blood lipid profile of subjects (r...

The selective recovery of heavy metals of Cu, Zn, Ni and Cr from a mixed plating sludge by sulfidation and oxidation treatment was targeted in this study. At first, the mixed plating sludge was simultaneously subjected to an extraction and Cu sulfidation process at pH=1.5 to dissolve heavy metals and to precipitate Cu as CuS. In the next step, the sulfidation treatment of Zn was carried out at ...

Abstract The amino acid l -methionine is an essential and commonly used as a feed supplement in terrestrial animals. It less suitable for marine organisms because it readily excreted. also highly water soluble this results loss of the eutrophication water. To address these problems, dipeptide dl -methionyl- (trade name: AQUAVI Met-Met) has been developed dedicated methionine source aquaculture....

A method for the preconcentration and speciation of chromium in seawater was developed. On-line preconcentration and determination were carried out by using inductively coupled plasma atomic emission spectrometry (ICP-AES) with dual mini-columns containing a chelating resin. In this system, Cr(III) was collected on the first column. The effluent containing residual chromium from the first colum...