TY - JOUR
T1 - Determination of main influence mechanism of fulvic acid on arsenic removal by ferric chloride
AU - Meng, Xiaoguang
AU - Xu, Sihang
AU - Ji, Meng
AU - Shi, Qiantao
AU - Guha, Biswarup
AU - Mascarenhas, Kelly
AU - Lippincott, Lee
AU - Zhang, Wen
AU - Ma, Qingquan
N1 - Publisher Copyright:
© 2024
PY - 2024
Y1 - 2024
N2 - In this study, synthetic wastewater containing 110 µg/L arsenate (As(V)), 0-20 mg/L fulvic acid (FA), and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+. The mechanisms of FA and phosphate effects on As(V) removal by ferric chloride were determined using 0.22-10 µm pore-size filtration, Zetasizer analysis, and in situ flow through cell ATR-FTIR. The results showed that up to 20 mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V) by the precipitates. When FA concentration increased from 0 to 20 mg/L, the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs from larger than 10 µm to smaller than 1 µm. In the presence of 5-20 mg/L FA, 46%-63% As(V) was adsorbed onto the flocs with particle size in the range of 0.45-1 µm. On the other hand, phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V) concentration because it competed with As(V) for adsorption sites on ferric hydroxide precipitates. The addition of 5 mg/L cationic organic flocculant significantly reduced the effect of FA on As(V) removal, but did not reduce the effect of phosphate on As(V) removal. The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.
AB - In this study, synthetic wastewater containing 110 µg/L arsenate (As(V)), 0-20 mg/L fulvic acid (FA), and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+. The mechanisms of FA and phosphate effects on As(V) removal by ferric chloride were determined using 0.22-10 µm pore-size filtration, Zetasizer analysis, and in situ flow through cell ATR-FTIR. The results showed that up to 20 mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V) by the precipitates. When FA concentration increased from 0 to 20 mg/L, the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs from larger than 10 µm to smaller than 1 µm. In the presence of 5-20 mg/L FA, 46%-63% As(V) was adsorbed onto the flocs with particle size in the range of 0.45-1 µm. On the other hand, phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V) concentration because it competed with As(V) for adsorption sites on ferric hydroxide precipitates. The addition of 5 mg/L cationic organic flocculant significantly reduced the effect of FA on As(V) removal, but did not reduce the effect of phosphate on As(V) removal. The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.
KW - Adsorption
KW - Arsenic
KW - Centrifugation
KW - Coagulation
KW - Ferric chloride
KW - Filtration
KW - Fulvic acid
KW - Phosphate
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U2 - 10.1016/j.jes.2023.12.019
DO - 10.1016/j.jes.2023.12.019
M3 - Article
AN - SCOPUS:85184075707
SN - 1001-0742
VL - 153
SP - 22
EP - 29
JO - Journal of Environmental Sciences (China)
JF - Journal of Environmental Sciences (China)
ER -