Kinetic and Mechanistic Study of the Reduction of Chromium(VI) by Lactic Acid

Ji, Shan; Wang, Fang; Song, Chao; He-ye, Wang

doi:10.1155/2008/314045

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…A comparative study of our method with other reductants is presented in SI Table S4. This result compares well to the existing results in literature. ,,− In particular, the rate constant obtained for the naturally derived flavonoids were very low with QPP being the lowest at 0.0259 mol –1 .L.S 1– . However, there was no significant change in the rate of reaction when the concentration of QCR, QPP, or QSA was doubled indicating a zero order dependence with respect to the concentration of the reductants.…”

Section: Resultssupporting

confidence: 90%

Reduction of Hexavalent Chromium Using Naturally-Derived Flavonoids

Okello

Mwilu

Noah

et al. 2012

Environ. Sci. Technol.

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Quercetin is a naturally occurring flavonoid that is known to form complexes with metals; a process that reduces the environmental availability of toxic metals such as chromium. We hereby report the first evidence of the removal of Cr(VI) fromenvironmental samples using quercetin (QCR) and two synthetic derivatives: namely quercetin pentaphosphate (QPP) and quercetin sulfonic acid (QSA). We successfully synthesized both QPP andQSA using simple procedures while characterizing them with UV-vis spectroscopy, H1-NMR,13C NMR,31P-NMR, and LC-MS techniques. The solubility of QPP was found to be 840 mg/mL and aqueous solutions of both QPP and QSA were stable for over a period of 1 year. Quercetin and these derivatives were subsequently utilized for the reduction of Cr(VI) and QCR was found to have a higher reduction efficiency of 99.8% (30 min), followed by QPP/palladium nanoparticles mixture (PdNPs) at 96.5% (60 min), and finally QSA/PdNPs mixtures at 91.7% (60 min). PdNPs catalyst increased the efficiency by∼36.5% while a change in operating temperature from 25 to 45°C improved the efficiency by∼46.8%. Electron paramagnetic resonance spectroscopy was used to confirm the presence of Cr (III) in the reaction products. This reduction approach was validated in environmental (Binghamton University) BU and standard reference material (BRS)soil samples. Results showed that the analysis could be completed within one hour and the efficiency was higher in BU soil than in BRS soil by 16.1%. QPP registered the highest % atom economy of 94.6%. This indicates enhanced performance compared tobio remediation approach that requires several months to achieve about 90% reduction efficiency.

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Section: Resultssupporting

confidence: 90%

Reduction of Hexavalent Chromium Using Naturally-Derived Flavonoids

Okello

Mwilu

Noah

et al. 2012

Environ. Sci. Technol.

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“…Recently, Pd and carbon-based Pd nanomaterials have been widely exploited as catalysts for the reduction of toxic Cr(VI). − Nonetheless, for various catalyst systems investigated thus far, the achievable activity and selectivity are still far from the demands for practical applications. In addition, a wide variety of reagents, namely formic acid (FA), − sulfur, hydrogen sulfide, n -butanol, lactic acid, and flavonoids have been used as reducing agent during the reduction of Cr(VI) to Cr(III). It is noteworthy that reaction systems employing some of these reducing agents may suffer from drawbacks such as safety, toxicity, and operation costs.…”

Section: Resultsmentioning

confidence: 99%

Biomass Derived Sheet-like Carbon/Palladium Nanocomposite: An Excellent Opportunity for Reduction of Toxic Hexavalent Chromium

Veerakumar

Thanasekaran

Lin

et al. 2017

ACS Sustainable Chem. Eng.

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Palladium nanoparticles (Pd NPs) immobilized on a garlic skin-derived activated carbons (GACs) is reported. The morphology, structure, surface compositions, and textural properties of the GACs and Pd@GAC catalyst were investigated by a variety of physicochemical characterization techniques, which revealed a dispersion of Pd NPs with average particle size of ca. 21 nm on sheet-like graphitized GACs with surface areas and pore volumes as high as 1836 m2 g–1 and 0.89 cm3 g–1, respectively. As a result, the Pd@GAC with a Pd loading of ca. 1–2 wt% exhibited superior activity for catalytic reduction of toxic Cr(VI) to Cr(III) surpassing most metal-based catalysts reported in the literature. As evidenced by a comprehensive UV–vis spectrophotometric study, the eco-friendly Pd@GAC catalyst reported herein, which can be facilely prepared with biowaste feedstocks, also showed excellent catalytic performances for efficient reduction of Cr(VI) with extraordinary stability and recyclability over at least five repeated catalytic test cycles.

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“…These organic ligands are very effective in reducing Cr(VI) into Cr(III). 6,10 Other organic ligands that are effective in Cr(VI) reduction include ascorbic acid, 11 lactic acid, 12 and bacterial exopolymeric substances. 13 Although a number of studies report reduction of Cr(VI) in systems using divalent iron 5,6,9,10,14 or zerovalent iron 15−18 as the catalyst and/or reductant, only a few reports are available using other metals with variable oxidizing states.…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, the synergistic activities of Fe(II), organic molecules, and suitable clay mineral surfaces can accelerate the reduction reaction in the soil environment. ,, Low molecular weight organic ligands such as citrate, oxalate, salicylate, and tartrate are abundant in the natural soil and water environment as a result of microbial decomposition of organic matter and plant root exudates. These organic ligands are very effective in reducing Cr(VI) into Cr(III). , Other organic ligands that are effective in Cr(VI) reduction include ascorbic acid, lactic acid, and bacterial exopolymeric substances …”

Section: Introductionmentioning

confidence: 99%

Manganese(II)-Catalyzed and Clay-Minerals-Mediated Reduction of Chromium(VI) by Citrate

Sarkar

Naidu

Krishnamurti

et al. 2013

Environ. Sci. Technol.

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Unlike lower valent iron (Fe), the potential role of lower valent manganese (Mn) in the reduction of hexavalent chromium (Cr(VI)) in soil is poorly documented. In this study, we report that citrate along with Mn(II) and clay minerals (montmorillonite and kaolinite) reduce Cr(VI) both in aqueous phase and in the presence of dissolved organic carbon (SDOC) extracted from a forest soil. The reduction was favorable at acidic pH (up to pH 5) and followed the pseudo-first-order kinetic model. The citrate (10 mM) + Mn(II) (182.02 μM) + clay minerals (3% w/v) system in SDOC accounted for complete reduction of Cr(VI) (192.32 μM) in about 72 h at pH 4.9. In this system, citrate was the reductant, Mn(II) was a catalyst, and the clay minerals acted as an accelerator for both the reductant and catalyst. The clay minerals also serve as a sink for Cr(III). This study reveals the underlying mechanism of the Mn(II)-induced reduction of Cr(VI) by organic ligand in the presence of clay minerals under certain environmental conditions.

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Kinetic and Mechanistic Study of the Reduction of Chromium(VI) by Lactic Acid

Cited by 5 publications

References 18 publications

Reduction of Hexavalent Chromium Using Naturally-Derived Flavonoids

Reduction of Hexavalent Chromium Using Naturally-Derived Flavonoids

Biomass Derived Sheet-like Carbon/Palladium Nanocomposite: An Excellent Opportunity for Reduction of Toxic Hexavalent Chromium

Manganese(II)-Catalyzed and Clay-Minerals-Mediated Reduction of Chromium(VI) by Citrate

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