title: Remediation of organic and inorganic arsenic contaminated groundwater using a nanocrystalline TiO2-based adsorbent.
abstract: A nanocrystalline TiO2-based adsorbent was evaluated for the simultaneous removal of As(V), As(III), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in contaminated groundwater. Batch experimental results show that As adsorption followed pseudo-second order rate kinetics. The competitive adsorption was described with the charge distribution multi-site surface complexation model (CD-MUSIC). The groundwater containing an average of 329 microg L(-1) As(III), 246 microg L(-1) As(V), 151 microg L(-1) MMA, and 202 microg L(-1) DMA was continuously passed through a TiO2 filter at an empty bed contact time of 6 min for 4 months. Approximately 11,000, 14,000, and 9900 bed volumes of water had been treated before the As(III), As(V), and MMA concentration in the effluent increased to 10 microg L(-1). However, very little DMA was removed. The EXAFS results demonstrate the existence of a bidentate binuclear As(V) surface complex on spent adsorbent, indicating the oxidation of adsorbed As(III).
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China. cyjing@rcees.ac.cn
authors.forename: Chuanyong
authors.initials: C
authors.lastname: Jing
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Meng
authors.forename: Edwin
authors.initials: E
authors.lastname: Calvache
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang