Reduction of Hexavalent Chromium in Aqueous Solutions by Polypyrrole

Chang, Wei; German, Sean R.; Basak, Sanjay; Rajeshwar, Krishnan

doi:10.1149/1.2056247

Cited by 86 publications

(62 citation statements)

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“…Scans of the solution were obtained every 10 min over a period of 3 h and show the removal of Cr(VI) from the solution. This is consistent with the reduction of Cr(VI) by PPy at other substrates [17][18][19][20][21][22]. The PPy was grown to a thickness of 0.5, 1.0 and 5.0 lm and similar UV-Vis experiments were performed in order to assess the effect of polymer thickness.…”

Section: Methodssupporting

confidence: 79%

“…Investigated remediation techniques include electrochemical methods [8,9], the use of ferrous iron [7], photocatalysis utilising UV illumination of titanium [10,11] or zinc oxides [12] and a number of other interesting methods including the implementation of copper, hydrogen peroxide, hydrogen sulphide and methylated yeast biomass [13][14][15][16]. In the past number of years the use of conducting polymerbased materials in Cr(VI) remediation has arisen as an interesting area of research [17,18]. Typically, a substrate is coated with a layer of conducting polymer, which is then used to reduce the toxic Cr(VI) to Cr(III), Eq.…”

Section: Introductionmentioning

confidence: 99%

“…Wei et al [18] described the use of a PPy-coated platinum mesh in reducing the Cr(VI) concentration in acidic solutions. The process involved first depositing PPy on the platinum substrate then reducing it in a conducting solution, in this case 0.1 mol dm -3 KCl.…”

Section: Introductionmentioning

confidence: 99%

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Remediation of chromium(VI) at polypyrrole-coated titanium

et al. 2009

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The application of conducting polypyrrole (PPy) and polyaniline (PAni) coated substrates in remediation of chromium, Cr(VI), is an area of considerable interest. Here, we discuss the implementation of PPy-coated titanium as a new material for the reduction of Cr(VI) to the less toxic trivalent state, Cr(III). An alkaline-peroxide based etching process was used to ensure the adhesion of the PPy coatings to the underlying titanium. The PPy films showed excellent resistance to acidic Cr(VI) solutions and remained adherent after continuous exposure to the solutions. In order to optimise the remediation process a number of experimental parameters were investigated, including the thickness of the PPy coating, the reduction potential used in pre-treatment of the PPy and the degree of solution agitation. The durability of the materials on exposure to the Cr(VI) test solutions made them suitable for repeated remediation experiments. Following several test-runs, the cleanup efficiency of the material was found to decrease slightly, however, increasing the exposure/experiment time resulted in significantly improved cleanup ability.

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Section: Methodssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Remediation of chromium(VI) at polypyrrole-coated titanium

et al. 2009

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“…More recently, it has been shown that conducting polypyrrole films can be used to reduce Cr(VI), opening up the possibility of a new remediation-control technology [7][8][9][10][11][12]. Polypyrrole (PPy) is a well-known conducting polymer and can undergo good reversibility between its conducting and insulating states.…”

Section: Introductionmentioning

confidence: 99%

Reduction of hexavalent chromium at a polypyrrole-coated aluminium electrode: Synergistic interactions

Conroy

Breslin

2004

Journal of Applied Electrochemistry

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Adherent polypyrrole films were electropolymerized from a tosylic acid solution onto an aluminium substrate and used for the reduction of Cr(VI). The reduction of Cr(VI) to the trivalent state was found to proceed by pseudofirst-order kinetics with an activation energy barrier of 15.13 kJ mol )1 . This catalyst could be regenerated by reducing the composite at a sufficiently negative potential, in the absence of Cr(VI). However, it was found that the catalyst functioned also through a self-sustained regeneration mechanism. In this mechanism, Cr(VI) was reduced by PPy 0 to generate PPy þ , but the PPy þ was subsequently reduced to PPy 0 by oxidation of the aluminium substrate, thus regeneration of the catalytic PPy 0 surface giving rise to a synergistic action between the polypyrrole and the aluminium substrate.

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“…Cr(III) is also an important micronutrient in the biological activity of insulin, is relatively stable and has low solubility in aqueous solution. The compounds of Cr(III) are reported to be 10-100 times less toxic than those of Cr(VI) (Wei et al 1993).…”

Section: Introductionmentioning

confidence: 99%

Conjunctive effect of CMC–zero-valent iron nanoparticles and FYM in the remediation of chromium-contaminated soils

et al. 2013

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Chromium is an important industrial metal used in various products and processes but at the same time causing lethal environmental hazards. Remediation of Cr-contaminated soils poses both technological and economic challenges, as conventional methods are often too expensive and difficult to operate. Zero-valent iron particles at nanoscale are proposed to be one of the important reductants of Cr(VI), transforming the same into nontoxic Cr(III). In the present investigation, soils contaminated with Cr(VI) are allowed to react with the various loadings of zero-valent iron nanoparticles (Fe 0 ) for a reaction period of 24 h. Fe 0 nanoparticles were synthesized by the reduction of ferrous sulfate in the presence of sodium borohydride and stabilized with carboxy methyl cellulose and were characterized by scanning electron microscopy, energy dispersion spectroscopy, X-ray diffraction, UV-vis spectrophotometer, Fourier transform-infra red spectrophotometer, Raman spectroscopy, dynamic light scattering technique and zeta potential. Further, this work demonstrates the potential utilization of farm yard manure (FYM) and Fe 0 nanoparticles in combination and individually for the effective remediation of Cr(VI)-contaminated soils. An increase in the reduction of Cr(VI) from 60 to 80 % was recorded with the increase in the loading of Fe 0 nanoparticles from 0.1 to 0.3 mg/100 g individually and in combination with FYM ranging from 50 to 100 mg/100 g soil.

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Reduction of Hexavalent Chromium in Aqueous Solutions by Polypyrrole

Cited by 86 publications

References 0 publications

Remediation of chromium(VI) at polypyrrole-coated titanium

Remediation of chromium(VI) at polypyrrole-coated titanium

Reduction of hexavalent chromium at a polypyrrole-coated aluminium electrode: Synergistic interactions

Conjunctive effect of CMC–zero-valent iron nanoparticles and FYM in the remediation of chromium-contaminated soils

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