Remediation of hexavalent chromium contamination in chromite ore   processing residue by sodium dithionite and sodium phosphate addition   and its mechanism

doi:10.1016/j.jenvman.2017.01.031

CORC > 北京大学 > 环境科学与工程学院

	Remediation of hexavalent chromium contamination in chromite ore processing residue by sodium dithionite and sodium phosphate addition and its mechanism
	Li, Yunyi ; Cundy, Andrew B. ; Feng, Jingxuan ; Fu, Hang ; Wang, Xiaojing ; Liu, Yangsheng
刊名	JOURNAL OF ENVIRONMENTAL MANAGEMENT
	2017
关键词	Cr(VI) Na2S2O4 Na3PO4 COPR Remediation Reductive precipitation ZERO-VALENT IRON NANOSCALE ZEROVALENT IRON SITU REDOX MANIPULATION CALCIUM POLYSULFIDE CR(VI) REDUCTION FERROUS SULFATE SOLID-WASTE SOIL CHROMATE IMMOBILIZATION
DOI	10.1016/j.jenvman.2017.01.031
英文摘要	Large amounts of chromite ore processing residue (COPR) wastes have been deposited in many countries worldwide, generating significant contamination issues from the highly mobile and toxic hexavalent chromium species (Cr(VI)). In this study, sodium dithionite (Na2S2O4) was used to reduce Cr(VI) to Cr(III) in COPR containing high available Fe, and then sodium phosphate (Na3PO4) was utilized to further immobilize Cr(III), via a two-step procedure (TSP). Remediation and immobilization processes and mechanisms were systematically investigated using batch experiments, sequential extraction studies, X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Results showed that Na2S2O4 effectively reduced Cr(VI) to Cr(III), catalyzed by Fe(III). The subsequent addition of Na3PO4 further immobilized Cr(III) by the formation of crystalline CrPO4 center dot 6H(2)O. However, addition of Na3PO4 simultaneously with Na2S2O4 (via a one-step procedure, OSP) impeded Cr(VI) reduction due to the competitive reaction of Na3PO4 and Na2S2O4 with Fe(III). Thus, the remediation efficiency of the TSP was much higher than the corresponding OSP. Using an optimal dosage in the two-step procedure (Na2S2O4 at a dosage of 12x the stoichiometric requirement for 15 days, and then Na3PO4 in a molar ratio (i.e. Na3PO4: initial Cr(VI)) of 4:1 for another 15 days), the total dissolved Cr in the leachate determined via Toxicity Characteristic Leaching Procedure (TCLP Cr) testing of our samples was reduced to 3.8 mg/L (from an initial TCLP Cr of 112.2 mg/L, i.e. at >96% efficiency). (C) 2017 Elsevier Ltd. All rights reserved.; National Natural Science Foundation of China [21077002]; Ministry of Environmental Protection [201009006]; National Science and Technology Ministry [2014BAC12B01]; China Scholarship Council (CSC); SCI(E); ARTICLE; 100-106; 192
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/473841]
专题	环境科学与工程学院
推荐引用方式 GB/T 7714	Li, Yunyi,Cundy, Andrew B.,Feng, Jingxuan,et al. Remediation of hexavalent chromium contamination in chromite ore processing residue by sodium dithionite and sodium phosphate addition and its mechanism[J]. JOURNAL OF ENVIRONMENTAL MANAGEMENT,2017.
APA	Li, Yunyi,Cundy, Andrew B.,Feng, Jingxuan,Fu, Hang,Wang, Xiaojing,&Liu, Yangsheng.(2017).Remediation of hexavalent chromium contamination in chromite ore processing residue by sodium dithionite and sodium phosphate addition and its mechanism.JOURNAL OF ENVIRONMENTAL MANAGEMENT.
MLA	Li, Yunyi,et al."Remediation of hexavalent chromium contamination in chromite ore processing residue by sodium dithionite and sodium phosphate addition and its mechanism".JOURNAL OF ENVIRONMENTAL MANAGEMENT (2017).