Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.17 (PCE)
 1,301 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study presents an experiment which characterizes reductive dechlorination of tetrachloroethylene (PCE) by green rusts (GRs) in the presence of Pt using a batch reactor system. Relative to GR alone, the rate of PCE reduction in GR suspensions was greatly enhanced with the addition of Pt(IV) (95% of PCE was removed in 30 h). PCE was mostly transformed to a nonchlorinated byproduct, acetylene rather than trichloroethylene, and the carbon mass recovery was 98% at the last sampling point. The reduction of PCE was four times faster for GR-F(Pt) than for GR-CO3(Pt), mainly due to the higher Fe(ll) content of GR-F. The estimated kinetic rate constants of GR-Cl(Pt) increased significantly (i.e., 0.17, 0.21, and 1.01 h(-1), respectively) with an incremental addition of Pt from 0.5 to 2 mM. X-ray diffraction analysis showed the transformation of GR to magnetite as an oxidation product. X-ray photoelectron spectroscopy analysis revealed that the oxidation was coupled to the reduction of Pt (IV to 0) on the GR surfaces. The scanning electron microscope with energy dispersive spectrometer measurement showed the formation of Pt particles on the surfaces of GRs modified with the Pt(IV).
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PMID:Enhanced degradation of tetrachloroethylene by green rusts with platinum. 1852 18

In this study, we characterize the reductive dechlorination of tetrachloroethene (PCE) by nano-sized mackinawite (nFeS) with cobalamin (Cbl(III)) at a high pH and investigate the effects of environmental factors, including the concentrations of the target contaminant, reductant, and catalyst and suspension ions on the dechlorination kinetics of PCE. Ninety five percent of the PCE was degraded by nFeS with Cbl(III) in 15 h. Cyclic voltammetry conducted with regard to the reductive dechlorination showed a higher redox potential of mackinawite under a high-pH condition (-1.01 V), suggesting that the oxidation state of the central cobalt ion in the cobalamin could be reduced to Cbl(I). The change of cobalamin species on the nFeS surface was verified under different pH conditions by UV-vis spectroscopy. The rate constant of PCE dechlorination increased from 0.1582 to 0.4284 h(-1) due to the increase in the nFeS content (2.085-20.85 g/L). As the concentration of Cbl(III) increased from 0 to 0.5 mM, the dechlorination kinetics of PCE was accelerated (0-1.4091 h(-1)) but reached a state of equilibrium from 0.5 to 1 mM. The increase in the initial PCE concentration (0.035-1.0 mM) slowed down the dechlorination kinetics (0.2036-0.0962 h(-1)). The dechlorination kinetics was enhanced by 1.5-11 times when 10 mM of ions (Na(+), K(+), Mg(2+), Ca(2+), CO3(2-), SO4(2-), and NO3(-)) were added, while an addition of HCO3 decelerated it by 10 times. This study can provide background knowledge pertaining to the PCE dechlorination by a natural reductant under a high-pH condition and the effect of environmental factors on the dechlorination kinetics for the development of novel remediation technologies.
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PMID:Enhanced reductive dechlorination of tetrachloroethene by nano-sized mackinawite with cyanocobalamin in a highly alkaline condition. 2559 Jun 8