Performance and mechanism of simultaneous removal of chromium and arsenate by Fe(II) from contaminated groundwater

Xiaohong Guan; Haoran Dong; Jun Ma; Irene M.C. Lo; Xiaomin Dou

doi:10.1016/j.seppur.2011.04.034

Performance and mechanism of simultaneous removal of chromium and arsenate by Fe(II) from contaminated groundwater

Xiaohong Guan^*
, Haoran Dong
, Jun Ma
, Irene M.C. Lo
, Xiaomin Dou

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

44 Scopus citations

Abstract

The feasibility and the mechanisms of simultaneous removal of chromium and arsenate by Fe(II) were investigated. In the absence of arsenate, chromium removal by Fe(II) increased to the maximum with increasing pH from ∼4 to ∼7 and then decreased with further increase in pH. Chromium removal by Fe(II) was controlled by the rate of Cr(VI) reduction by Fe(II) and the solubility of Fe_0.75Cr_0.25(OH)₃ at pH ≤ 7, but by the extent of Cr(VI) reduction under alkaline conditions. The presence of arsenate resulted in a decrease in chromium removal by Fe(II) under neutral and alkaline conditions as a result of the depression in the magnitude of Cr(VI) reduction by Fe(II) and sequestration of the Fe_0.75Cr _0.25(OH)₃ and FeOOH precipitation by HAsO42-. Arsenate removal by Fe(II) alone was trivial but was improved significantly at pH 4-9 due to the presence of 10-30 μmol L^-1 chromate. It was the oxidative property of chromate that resulted in the oxidization of Fe(II) to Fe(III) concomitantly facilitating the removal of arsenate. Arsenate was removed by both adsorption and co-precipitation with Fe_0.75Cr_0.25(OH) ₃ and FeOOH precipitates. EXAFS results revealed that arsenate mainly coordinated with Fe(III) rather than Cr(III) and arsenate formed bidentate-binuclear complexes with FeO(OH) octahydra as evidenced by an average Fe-As(V) bond distance of 3.25-3.26 Å.

Original language	English
Pages (from-to)	179-185
Number of pages	7
Journal	Separation and Purification Technology
Volume	80
Issue number	1
DOIs	https://doi.org/10.1016/j.seppur.2011.04.034
State	Published - 12 Jul 2011
Externally published	Yes

Keywords

Arsenate
Chromate
Co-precipitation
Ferrous iron
Reduction

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10.1016/j.seppur.2011.04.034

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title = "Performance and mechanism of simultaneous removal of chromium and arsenate by Fe(II) from contaminated groundwater",

abstract = "The feasibility and the mechanisms of simultaneous removal of chromium and arsenate by Fe(II) were investigated. In the absence of arsenate, chromium removal by Fe(II) increased to the maximum with increasing pH from ∼4 to ∼7 and then decreased with further increase in pH. Chromium removal by Fe(II) was controlled by the rate of Cr(VI) reduction by Fe(II) and the solubility of Fe0.75Cr0.25(OH)3 at pH ≤ 7, but by the extent of Cr(VI) reduction under alkaline conditions. The presence of arsenate resulted in a decrease in chromium removal by Fe(II) under neutral and alkaline conditions as a result of the depression in the magnitude of Cr(VI) reduction by Fe(II) and sequestration of the Fe0.75Cr 0.25(OH)3 and FeOOH precipitation by HAsO42-. Arsenate removal by Fe(II) alone was trivial but was improved significantly at pH 4-9 due to the presence of 10-30 μmol L-1 chromate. It was the oxidative property of chromate that resulted in the oxidization of Fe(II) to Fe(III) concomitantly facilitating the removal of arsenate. Arsenate was removed by both adsorption and co-precipitation with Fe0.75Cr0.25(OH) 3 and FeOOH precipitates. EXAFS results revealed that arsenate mainly coordinated with Fe(III) rather than Cr(III) and arsenate formed bidentate-binuclear complexes with FeO(OH) octahydra as evidenced by an average Fe-As(V) bond distance of 3.25-3.26 {\AA}.",

keywords = "Arsenate, Chromate, Co-precipitation, Ferrous iron, Reduction",

author = "Xiaohong Guan and Haoran Dong and Jun Ma and Lo, \{Irene M.C.\} and Xiaomin Dou",

year = "2011",

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doi = "10.1016/j.seppur.2011.04.034",

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T1 - Performance and mechanism of simultaneous removal of chromium and arsenate by Fe(II) from contaminated groundwater

AU - Guan, Xiaohong

AU - Dong, Haoran

AU - Ma, Jun

AU - Lo, Irene M.C.

AU - Dou, Xiaomin

PY - 2011/7/12

Y1 - 2011/7/12

N2 - The feasibility and the mechanisms of simultaneous removal of chromium and arsenate by Fe(II) were investigated. In the absence of arsenate, chromium removal by Fe(II) increased to the maximum with increasing pH from ∼4 to ∼7 and then decreased with further increase in pH. Chromium removal by Fe(II) was controlled by the rate of Cr(VI) reduction by Fe(II) and the solubility of Fe0.75Cr0.25(OH)3 at pH ≤ 7, but by the extent of Cr(VI) reduction under alkaline conditions. The presence of arsenate resulted in a decrease in chromium removal by Fe(II) under neutral and alkaline conditions as a result of the depression in the magnitude of Cr(VI) reduction by Fe(II) and sequestration of the Fe0.75Cr 0.25(OH)3 and FeOOH precipitation by HAsO42-. Arsenate removal by Fe(II) alone was trivial but was improved significantly at pH 4-9 due to the presence of 10-30 μmol L-1 chromate. It was the oxidative property of chromate that resulted in the oxidization of Fe(II) to Fe(III) concomitantly facilitating the removal of arsenate. Arsenate was removed by both adsorption and co-precipitation with Fe0.75Cr0.25(OH) 3 and FeOOH precipitates. EXAFS results revealed that arsenate mainly coordinated with Fe(III) rather than Cr(III) and arsenate formed bidentate-binuclear complexes with FeO(OH) octahydra as evidenced by an average Fe-As(V) bond distance of 3.25-3.26 Å.

AB - The feasibility and the mechanisms of simultaneous removal of chromium and arsenate by Fe(II) were investigated. In the absence of arsenate, chromium removal by Fe(II) increased to the maximum with increasing pH from ∼4 to ∼7 and then decreased with further increase in pH. Chromium removal by Fe(II) was controlled by the rate of Cr(VI) reduction by Fe(II) and the solubility of Fe0.75Cr0.25(OH)3 at pH ≤ 7, but by the extent of Cr(VI) reduction under alkaline conditions. The presence of arsenate resulted in a decrease in chromium removal by Fe(II) under neutral and alkaline conditions as a result of the depression in the magnitude of Cr(VI) reduction by Fe(II) and sequestration of the Fe0.75Cr 0.25(OH)3 and FeOOH precipitation by HAsO42-. Arsenate removal by Fe(II) alone was trivial but was improved significantly at pH 4-9 due to the presence of 10-30 μmol L-1 chromate. It was the oxidative property of chromate that resulted in the oxidization of Fe(II) to Fe(III) concomitantly facilitating the removal of arsenate. Arsenate was removed by both adsorption and co-precipitation with Fe0.75Cr0.25(OH) 3 and FeOOH precipitates. EXAFS results revealed that arsenate mainly coordinated with Fe(III) rather than Cr(III) and arsenate formed bidentate-binuclear complexes with FeO(OH) octahydra as evidenced by an average Fe-As(V) bond distance of 3.25-3.26 Å.

KW - Arsenate

KW - Chromate

KW - Co-precipitation

KW - Ferrous iron

KW - Reduction

UR - https://www.scopus.com/pages/publications/79959755635

U2 - 10.1016/j.seppur.2011.04.034

DO - 10.1016/j.seppur.2011.04.034

M3 - 文章

AN - SCOPUS:79959755635

SN - 1383-5866

VL - 80

SP - 179

EP - 185

JO - Separation and Purification Technology

JF - Separation and Purification Technology

IS - 1

ER -

Performance and mechanism of simultaneous removal of chromium and arsenate by Fe(II) from contaminated groundwater

Abstract

Keywords

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