Arsenic Adsorption on Modified Clay Minerals in Contaminated Soil and Water:Impact of pH and Competitive Anions

Mukhopadhyay, R. and Sarkar, B. and Barman, A. and Datta, S.C. and Manjaiah, K.M. (2021) Arsenic Adsorption on Modified Clay Minerals in Contaminated Soil and Water:Impact of pH and Competitive Anions. Clean Soil Air Water, 49 (4). ISSN 1863-0650

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Abstract

This study evaluates the arsenic adsorption behavior of Fe-exchanged smectite and phosphate-bound kaolinite, in soil, tap water and double distilled water in the presence of competing anions such as silicate, phosphate, and sulfate, and at variable pH values. The maximum amounts of As adsorbed in soil are 620.6 and 607.6 µg g–1 at pH 5 by Fe-exchanged smectite and phosphate-bound kaolinite, respectively. The pH-modified Freundlich equation fits well (R2 > 0.96) to the adsorption data, distinguishing the effect of pH on adsorption. The coefficients of pH-value are 0.04 and 0.05 for phosphate-bound kaolinite and Fe-exchanged smectite, suggesting that low pH is suitable for the adsorption. The As adsorption is decreased in tap water at low pH compared to the soil due to the presence of iron (Fe2+/3+), sulfate, and bicarbonate in tap water. Among the competing anions in distilled water, phosphate is the most interfering anion for As adsorption. The competition coefficients of As-phosphate binary adsorption derived from the Sheindorf equation are 3.93 and 0.56 for Fe-exchanged smectite and phosphate-bound kaolinite at pH 5. The Fe-exchanged smectite can be used more effectively than phosphate-bound kaolinite for As remediation in systems having low pH (pH ≈5) and high phosphate concentration.

Item Type:
Journal Article
Journal or Publication Title:
Clean Soil Air Water
Additional Information:
This is the peer reviewed version of the following article:Mukhopadhyay, R., Sarkar, B., Barman, A., Datta, S. C., Manjaiah, K. M., Arsenic Adsorption on Modified Clay Minerals in Contaminated Soil and Water: Impact of pH and Competitive Anions. Clean – Soil, Air, Water 2021, 2000259. https://doi.org/10.1002/clen.202000259 which has been published in final form at https://onlinelibrary.wiley.com/doi/10.1002/clen.202000259 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2310
Subjects:
ID Code:
152364
Deposited By:
Deposited On:
05 Mar 2021 14:40
Refereed?:
Yes
Published?:
Published
Last Modified:
16 Jun 2021 09:04