title: Cr(VI)-contaminated groundwater remediation with simulated permeable reactive barrier (PRB) filled with natural pyrite as reactive material: Environmental factors and effectiveness.
abstract: Permeable reactive barriers (PRBs) are efficient technologies for in situ remediation of contaminated groundwater, the effectiveness of which greatly depends on the reactive media filled. Natural pyrite is an iron sulfide material with a very low content of iron and sulfur, and a mining waste which is a potential material for Cr(VI) immobilization. In this study, we conducted a series of batch tests to research the effects of typical environmental factors on Cr(VI) removal and also simulated PRB filled with natural pyrite to investigate its effectiveness, in order to find a both environmentally and economically fine method for groundwater remediation. Batch tests showed that pH had the significant impact on Cr(VI) removal with an apparently higher efficiency under acidic conditions, and dissolved oxygen (DO) would inhibit Cr(VI) reduction; a relatively high initial Cr(VI) concentration would decrease the rate of Cr(VI) sorption; ionic strength and natural organic matter resulted in no significant effects on Cr(VI) removal. Column tests demonstrated that the simulated PRB with natural pyrite as the reactive media was considerably effective for removing Cr(VI) from groundwater, with a sorption capability of 0.6222 mg Cr per gram of natural pyrite at an initial Cr(VI) concentration of 10mg/L at pH 5.5 in an anoxic environment.
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment of Ministry of Education, Chongqing University, Chongqing 400044, PR China. Electronic address: liuyuanyuan@cqu.edu.cn.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment of Ministry of Education, Chongqing University, Chongqing 400044, PR China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Mou
authors.affiliation: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; BERIS Engineering and Research Cooperation, Baotou, Inner Mongolia, 014010, PR China.
authors.forename: Liqun
authors.initials: L
authors.lastname: Chen
authors.affiliation: Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, PR China.
authors.forename: Zakaria A
authors.initials: ZA
authors.lastname: Mirza
authors.affiliation: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000302:isolation & purification*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D060587:Groundwater / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010539:Permeability; D013440:Sulfides / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D013440:Sulfides; D014874:Water Pollutants, Chemical; D002857:Chromium; C011342:pyrite; C074702:chromium hexavalent ion; D007501:Iron; D010100:Oxygen
keywords: Cr(VI)/Hexavalent chromium; Environmental factors; Groundwater; Natural pyrite; PRBs