The role of different functional groups in a novel adsorption-complexation-reduction multi-step kinetic model for hexavalent chromium retention by undissolved humic acid

Zhang, Jia; Yin, Huilin; Chen, Linpeng; Liu, Fei; Chen, Honghan

doi:10.1016/j.envpol.2017.10.120

Cited by 78 publications

(27 citation statements)

References 33 publications

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“…The lower oxidation state of chromium can be precipitated after reduction of Cr(VI) (Hsu et al 2009). In the soil enriched with Fe and Mn oxides, Cr(VI) can be adsorbed through sorption process under acidic condition (Zhang et al 2017). Cr(VI) is a powerful oxidant which can oxidize the biomolecules and subsequently induce toxicity.…”

Section: Introductionmentioning

confidence: 99%

Potentiality of waste human hair towards removal of chromium(VI) from solution: kinetic and equilibrium studies

Mondal

Basu

2019

Appl Water Sci

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Industrial and agricultural activities discharges huge amount of hazardous pollutants that lead to massive environmental pollution and health hazards. Keratin is a fascinating protein and useful biopolymer, which is usually found in wool, human hair, nails, feathers, etc. The present research deals with the potentiality of human hair towards removal of hexavalent chromium from aqueous solution through batch mode. The adsorbent was characterized by pH ZPC and SEM study. The Cr(VI) adsorption was studied with the help of different process parameters, viz. initial concentration, contact time, adsorbent dose, pH, and temperature. Results revealed that Cr(VI) adsorption by human hair was highly pH sensitive. Maximum Cr(VI) was adsorbed from water at pH 1.0. Study of temperature effect on chromium adsorption confirmed the endothermic behaviour of the process. On the other hand, thermodynamic properties were also calculated and found that physisorption was dominant with activation energy of 0.385 kJ mol −1. Kinetic study revealed that pseudo-second-order model was followed by the adsorption process. Adsorption equilibrium was analysed with Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. Results showed that the adsorption system followed both Langmuir and Freundlich isotherms with Langmuir adsorption capacity of 9.852 mg g −1 , which was compared with other adsorbents and observed that the performance of the present adsorbent is better than others. Finally, it can be concluded that human hair could be an alternative chief low-cost waste material for decontamination of heavy metals from an aqueous medium.

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Section: Introductionmentioning

confidence: 99%

Potentiality of waste human hair towards removal of chromium(VI) from solution: kinetic and equilibrium studies

Mondal

Basu

2019

Appl Water Sci

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“…These groups become protonated at low pH and thus aid in binding of Cr (VI) anions. Zang et al reported complexation of carboxyl groups with Cr (VI) as a precondition for Cr (VI) reduction [49].…”

Section: Resultsmentioning

confidence: 99%

Biotransformation of chromium by root nodule bacteria Sinorhizobium sp. SAR1

et al. 2019

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The present study aims to address the problem of chromium (Cr) toxicity by providing important insights into the mechanisms involved in its bioremediation. Among the 22 Rhizobium and Sinorhizobium isolates obtained from Sesbania sesban root nodules, Sinorhizobium sp. SAR1 (JX174035.1) tolerated the maximum Cr concentration (1mM) and hence was used for further studies. The excess secretion of extra polymeric substances, as seen from scanning electron micrographs, could be a probable mechanism of adaptation to the Cr stress. The Energy dispersive X-ray spectroscopy data did not show any peaks of Cr. The biosorption studies done on the isolate gave maximum adsorption capacity as 285.71mg/g. The isotherm studies showed a better fit to Langmuir isotherm. The Weber and Morris plot established that the phenomenon of adsorption was governed by film diffusion mechanism. The FTIR analysis suggested the role of cell wall components and extracellular polymeric substances in Cr adsorption to the biomass of Sinorhizobium . On the basis of these results a compiled mechanism of Cr (VI) adsorption and its biotransformation into Cr (III) by Sinorhizobium sp. SAR1 is explained. This work outlines a comprehensive detail for the exact phenomenon of Cr biotransformation by Sinorhizobium sp. SAR1. These results may further help in developing and enhancing effective bioremediation approaches.

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“…As indicated, the absorbance bands can be found at the bands of 1720, 1639, 1384, 1230 and 1031 cm À1 , which can be attributed to carboxyl, carbonyl, methyl, phenol and hydroxyl respectively. [36][37][38][39][40][41][42][43] Because the methyl has been determined to be relatively resistant to Cr(VI) oxidation, 44,45 the ratios of absorbances at other functional groups bands to the absorbance of methyl were used to indicate the variation of carboxyl, carbonyl, phenol and hydroxyl, and the results are shown in Fig. S16 and S17.…”

Section: Adsorption-reduction Mechanism Of Cr(vi) Retentionmentioning

confidence: 99%

“…† As indicated, compared with the blank control group (without Cr(VI)), the ratio of carboxyl, carbonyl, phenol and hydroxyl to methyl decreased signicantly with pH deceasing and initial Cr(VI) concentration increasing, especially phenol and carboxyl, which have been determined to act as the main electron donor and complexation site for Cr(VI) respectively in our previous studies. 44 Considering that the maximum TOC concentration in solution was about 110 mg C L À1 , which only accounted for less than 2% of the mass of SOM, therefore, the reduction of Cr(VI) in solution by DOM can be neglected. This implied that the reduction of Cr(VI) mainly occurred on the soil particles, meaning that the retention of Cr(VI) by black soil more tended to follow the adsorption-reduction mechanism.…”

Section: Adsorption-reduction Mechanism Of Cr(vi) Retentionmentioning

confidence: 99%

Mechanism and modeling of hexavalent chromium interaction with a typical black soil: the importance of the relationship between adsorption and reduction

et al. 2019

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The role of different functional groups in a novel adsorption-complexation-reduction multi-step kinetic model for hexavalent chromium retention by undissolved humic acid

Cited by 78 publications

References 33 publications

Potentiality of waste human hair towards removal of chromium(VI) from solution: kinetic and equilibrium studies

Potentiality of waste human hair towards removal of chromium(VI) from solution: kinetic and equilibrium studies

Biotransformation of chromium by root nodule bacteria Sinorhizobium sp. SAR1

Mechanism and modeling of hexavalent chromium interaction with a typical black soil: the importance of the relationship between adsorption and reduction

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