Kinetic Studies on Hexavalent Chromium Reduction

Basu, Anupam; Saha, Bidyut

doi:10.4236/ajac.2010.11003

Cited by 18 publications

(5 citation statements)

References 27 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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“…Its reduction occurs in the cell cytoplasm. The cited work [74] used micelles to mimic the cellular membranes as a model to gain information on the process occurring in the body. Spectrophotometric kinetic experiments were carried out by monitoring the decay of oxidant [Cr 6+ ] at 415 nm at different time intervals.…”

Section: Interaction Of Metal Ions With Lipid Membrane Mimicking Systemsmentioning

confidence: 99%

Quantitative Analysis of the Interactions of Metal Complexes and Amphiphilic Systems: Calorimetric, Spectroscopic and Theoretical Aspects

et al. 2022

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Metals and metal-based compounds have many implications in biological systems. They are involved in cellular functions, employed in the formation of metal-based drugs and present as pollutants in aqueous systems, with toxic effects for living organisms. Amphiphilic molecules also play important roles in the above bio-related fields as models of membranes, nanocarriers for drug delivery and bioremediating agents. Despite the interest in complex systems involving both metal species and surfactant aggregates, there is still insufficient knowledge regarding the quantitative aspects at the basis of their binding interactions, which are crucial for extensive comprehension of their behavior in solution. Only a few papers have reported quantitative analyses of the thermodynamic, kinetic, speciation and binding features of metal-based compounds and amphiphilic aggregates, and no literature review has yet addressed the quantitative study of these complexes. Here, we summarize and critically discuss the recent contributions to the quantitative investigation of the interactions of metal-based systems with assemblies made of amphiphilic molecules by calorimetric, spectrophotometric and computational techniques, emphasizing the unique picture and parameters that such an analytical approach may provide, to support a deep understanding and beneficial use of these systems for several applications.

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Kinetic Studies on Hexavalent Chromium Reduction

Cited by 18 publications

References 27 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

Quantitative Analysis of the Interactions of Metal Complexes and Amphiphilic Systems: Calorimetric, Spectroscopic and Theoretical Aspects

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