title: Remediation of trichloroethylene-contaminated groundwater by three modifier-coated microscale zero-valent iron.
abstract: Building a microscale zero-valent iron (mZVI) reaction zone is a promising in situ remediation technology for restoring groundwater contaminated by trichloroethylene (TCE). In order to determine a suitable modifier that could not only overcome gravity sedimentation of mZVI but also improve its remediation efficiency for TCE, the three biopolymers xanthan gum (XG), guargum (GG), and carboxymethyl cellulose (CMC) were employed to coat mZVI for surface modification. The suspension stability of the modified mZVI and its TCE removal efficiency were systematically investigated. The result indicated that XG as a shear-thinning fluid showed the most remarkable efficiency of preventing mZVI from gravity sedimentation and enhancing the TCE removal efficiency by mZVI. In a 480-h experiment, the presence of XG (3 g L(-1)) increased the TCE removal efficiency by 31.85 %, whereas GG (3 g L(-1)) and CMC (3 g L(-1)) merely increased by 15.61 and 9.69 % respectively. The pH value, Eh value, and concentration of ferrous ion as functions of the reaction time were recorded in all the reaction systems, which indicated that XG worked best in buffering the pH value of the solution and inhibiting surface passivation of mZVI.
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Qingdao, 266100, China.|College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Qingdao, 266100, China.|College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Xin
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Qingdao, 266100, China. zhxilai@ouc.edu.cn.|College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China. zhxilai@ouc.edu.cn.
authors.forename: Xilai
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Helmholtz Center for Environmental Research UFZ/TU Dresden, 034202, Leipzig, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Kolditz
authors.affiliation: Helmholtz Center for Environmental Research UFZ/TU Dresden, 034202, Leipzig, Germany.
authors.forename: Haibing
authors.initials: H
authors.lastname: Shao
mesh_terms: D060587:Groundwater / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D012996:Solutions; D014241:Trichloroethylene / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D011135:Polysaccharides, Bacterial; D012996:Solutions; D014874:Water Pollutants, Chemical; D014241:Trichloroethylene; D007501:Iron; C002563:xanthan gum
keywords: Carboxymethyl cellulose (CMC); Groundwater; Guar gum (GG); Microscale zero-valent iron (mZVI); Trichloroethylene (TCE); Xanthan gum (XG)