title: Highly efficient arsenic removal using a composite of ultrafine magnetite nanoparticles interlinked by silane coupling agents.
abstract: Arsenic (As) contamination in groundwater is a great environmental health concern and is often the result of contact between groundwater and arsenic-containing rocks or sediments and from variation of pH and redox potentials in the subsurface. In the past decade, magnetite nanoparticles (MNPs) have been shown to have high adsorption activity towards As. Alerted by the reported cytotoxicity of 5–12 nm MNP, we studied the adsorption behavior of 1.15 nm MNP and a MNP composite (MNPC), MNPs interlinked by silane coupling agents. With an initial concentration of As at 25 mg L(-1), MNPs exhibited high adsorption capacity for As(V) and As (III), 206.9 mg·g(-1) and 168.6 mg·g(-1) under anaerobic conditions, respectively, and 109.9 mg·g(-1) and 108.6 mg·g(-1) under aerobic conditions, respectively. Under aerobic conditions, MNPC achieved even higher adsorption capacity than MNP, 165.1 mg·g(-1) on As(V) and 157.9 mg·mg(-1) on As(III). For As(V) at 50 mg L(-1), MNPC achieved an adsorption capacity as high as 341.8 mg·g(-1), the highest in the literature. A kinetic study indicated that this adsorption reaction can reach equilibrium within 15 min and the rate constant of As(V) is about 1.9 times higher than that of As(III). These results suggested that MNPC can serve as a highly effective adsorbent for fast removal of As.
authors.affiliation: Department of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan. shuchichang@nchu.edu.tw
authors.forename: Shu-Chi
authors.initials: SC
authors.lastname: Chang
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Yu
authors.forename: Cheng-Hao
authors.initials: CH
authors.lastname: Li
authors.forename: Chin-Ching
authors.initials: CC
authors.lastname: Wu
authors.forename: Hao-Yun
authors.initials: HY
authors.lastname: Lei
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D007700:Kinetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D058185:Magnetite Nanoparticles; D012821:Silanes; D014874:Water Pollutants, Chemical; D001151:Arsenic