Remediation of arsenic-contaminated groundwater using media-injected permeable reactive barriers with a modified montmorillonite: sand tank studies.
A modified montmorillonite (MMT) was prepared using an acid activation-sodium activation-iron oxide coating method to improve the adsorption capacities of natural MMTs. For MMT, its interlamellar distance increased from 12.29 to 13.36 Å, and goethite (α-FeOOH) was intercalated into its clay layers. Two novel media-injected permeable reactive barrier (MI-PRB) configurations were proposed for removing arsenic from groundwater. Sand tank experiments were conducted to investigate the performance of the two MI-PRBs: Tank A was filled with quartz sand. Tank B was packed with quartz sand and zero-valent iron (ZVI) in series, and the MMT slurry was respectively injected into them to form reactive zones. The results showed that for tank A, total arsenic (TA) removal of 98.57% was attained within the first 60 mm and subsequently descended slowly to 88.84% at the outlet. For tank B, a similar spatial variation trend was observed in the quartz sand layer, and subsequently, TA removal increased to ≥99.80% in the ZVI layer. TA removal by MMT mainly depended on both surface adsorption and electrostatic adhesion. TA removal by ZVI mainly relied on coagulation/precipitation and adsorption during the iron corrosion. The two MI-PRBs are feasible alternatives for in situ remediation of groundwater with elevated As levels.
School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China.|Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, Beijing, 100083, China.
Ximing
X
Luo
CERI Eco Technology Co., Ltd., Beijing, 100053, China.
Haifei
H
Liu
Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, Beijing, 100083, China. huangguoxin_0@126.com.|Beijing Key Laboratory of Meat Processing Technology, China Meat Research Center, Beijing, 100068, China. huangguoxin_0@126.com.
Guoxin
G
Huang
Beijing Municipal Research Institute of Environmental Protection, Beijing, 100037, China.
Ye
Y
Li
Beijing Key Laboratory of Meat Processing Technology, China Meat Research Center, Beijing, 100068, China.
Yan
Y
Zhao
Beijing Key Laboratory of Meat Processing Technology, China Meat Research Center, Beijing, 100068, China.
Xu
X
Li
D000327:Adsorption; D001151:Arsenic / Q000032:analysis; D001546:Bentonite; D052918:Environmental Restoration and Remediation; D060587:Groundwater; D007501:Iron; D012822:Silicon Dioxide; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D001546:Bentonite; D012822:Silicon Dioxide; D007501:Iron; D001151:Arsenic
Arsenic; Groundwater; In situ remediation; Media-injected permeable reactive barriers (MI-PRBs); Modified montmorillonite (MMT); Zero-valent iron (ZVI)