title: Mechanism insights into enhanced trichloroethylene removal using xanthan gum-modified microscale zero-valent iron particles.
abstract: This report focuses on the enhancement in trichloroethylene (TCE) removal from contaminated groundwater using xanthan gum (XG)-modified, microscale, zero-valent iron (mZVI). Compared with bare mZVI, XG-coated mZVI increased the TCE removal efficiency by 30.37% over a 480-h experimental period. Because the TCE removal is attributed to both sorption and reduction processes, the contributions from sorption and reduction were separately investigated to determine the mechanism of XG on TCE removal using mZVI. The results showed that the TCE sorption capacity of mZVI was lower in the presence of XG, whereas the TCE reduction capacity was significantly increased. The FTIR spectra confirmed that XG, which is rich in hydrophilic functional groups, was adsorbed onto the iron surface through intermolecular hydrogen bonds, which competitively repelled the sorption and mass transfer of TCE toward reactive sites. The variations in the pH, Eh, and Fe(2+) concentration as functions of the reaction time were recorded and indicated that XG buffered the solution pH, inhibited surface passivation, and promoted TCE reduction by mZVI. Overall, the XG-modified mZVI was considered to be potentially effective for the in-situ remediation of TCE contaminated groundwater due to its high stability and dechlorination reactivity.
authors.affiliation: College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Xin
authors.affiliation: College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.affiliation: College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China. Electronic address: zhxilai@ouc.edu.cn.
authors.forename: Xilai
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Helmholtz Center for Environmental Research UFZ/TU Dresden, Leipzig 034202, Germany.
authors.forename: Haibing
authors.initials: H
authors.lastname: Shao
authors.affiliation: Helmholtz Center for Environmental Research UFZ/TU Dresden, Leipzig 034202, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Kolditz
mesh_terms: D006801:Humans; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D014241:Trichloroethylene / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D011135:Polysaccharides, Bacterial; D014874:Water Pollutants, Chemical; D014241:Trichloroethylene; D007501:Iron; C002563:xanthan gum
keywords: Groundwater pollution; Microscale zero-valent iron (mZVI); Trichloroethylene (TCE); Xanthan gum (XG)