LONG-TERM REDUCTION STABILIZATION OF HEXAVALENT CHROMIUM CONTAMINATED SOIL BY PYRITE
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摘要: 针对酸溶态占比高的Cr(Ⅵ)污染土壤还原解毒不彻底、后期易返黄的问题,确定了水溶态Cr(Ⅵ)快速还原、酸溶态Cr(Ⅵ)长效缓释还原的修复思路。试验考察了单独添加硫铁矿对Cr(Ⅵ)处理的效果,并采用FeSO4·7H2O、硫铁矿分步还原法探究处理后污染土壤的长效稳定性,进行了540 d的长期监测。结果表明:FeSO4·7H2O还原药剂长效性较差,在自然环境中容易发生氧化,失去还原效能,无法完全还原缓慢释放的酸溶态Cr(Ⅵ),有必要加入长效还原缓释药剂对酸溶态Cr(Ⅵ)进行持续还原。硫铁矿单独修复水溶态Cr(Ⅵ)为主的污染土壤,在添加20%的硫铁矿,反应14 d的条件下,土壤中Cr(Ⅵ)浸出浓度降至30.4 mg/L。采用FeSO4·7H2O和硫铁矿分步还原酸溶态Cr(Ⅵ)污染土壤,先加入2%的FeSO4·7H2O,养护3 d后再加入3%的硫铁矿反应27 d,Cr(Ⅵ)浸出浓度即降至0.29 mg/L,加入5%的硫铁矿,反应4 d后Cr(Ⅵ)浸出浓度即可降至0.43 mg/L,之后Cr(Ⅵ)浸出浓度保持稳定。经过540 d的长期监测未发现浸出浓度有上升情况。Abstract: In order to solve the problems of hexavalent chromium contaminated soil with a high proportion of acid-soluble, incomplete reduction and detoxification, and easy recovery in the later period, remediation idea of water-soluble hexavalent chromium rapid reduction and acid-soluble hexavalent chromium long-term reduction was determined. The experiments were designed to investigate the effect of adding pyrite alone to the treatment of hexavalent chromium, and explored the long-term stability of contaminated soil by step reduction of using ferrous sulfate and pyrite, and a 540-day long-term monitoring was carried out. The results showed:FeSO4·7H2O reducing agent was prone to oxidation in the natural environment and loosed its reducing power, leading to its poor long-term performance, and inability to fully reduce slow-release acid-soluble hexavalent chromium. It was necessary to add a long-acting reduction slow-release agent to continuously reduce acid-soluble hexavalent chromium. Pyrite alone could remediate water-soluble hexavalent chromium-contaminated soil, the leaching concentration of hexavalent chromium in soil decreased to 30.4 mg/L in the mixing of 20% pyrite, 14 days of reaction. Using ferrous sulfate and pyrite to reduce the hexavalent chromium contaminated soil mainly in acid soluble state: add 2% ferrous sulfate curing for 3 days and then add 3% pyrite for 27 days, the leaching concentration of hexavalent chromium droped to 0.29 mg/L; adding 5% pyrite, the leaching concentration of hexavalent chromium could be reduced to 0.43 mg/L after 4 days of reaction, after which the leaching concentration of hexavalent chromium remained stable. According to 540 days of long-term monitoring data, the leaching concentration did not rise.
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IARC. IARC monographs on the evaluation of carcino-genic risks to humans volume 49 chrome, nickel and welding[R]. Geneva: World Health Organization, 1997: 17-33. 王兴润, 李丽, 刘雪,等. 铬渣治理技术的应用进展及特点分析[J]. 中国给水排水, 2009, 25(4): 10-14. 纪柱. 铬渣长期堆存后的组成变化及对治理的影响[J]. 无机盐工业, 2006,38(9): 8-12. DERMATAS D, CHRYSOCHOOU M, MOON D H, et al. Ettringite induced heave in chromite ore processing residue (COPR) upon ferrous sulfate treatment[J]. Environmental Science & Technology, 2006, 40(18): 5786-5792. MOON D H, WAZNE M, DERMATAS D, et al. Long-term treatment issues with chromite ore processing residue (COPR): Cr6+ reduction and heave[J].Journal of Hazardous Materials, 2007, 143(3): 629-635. JAGUPILLA S C, MOON D H, WAZNE M, et al. Effects of particle size and acid addition on the remediation of chromite ore processing residue using ferrous sulfate [J]. Journal of Hazardous Materials, 2009, 168(1): 121-128. WANG X, ZHANG J D, WANG L L, et al. Long-term stability of FeSO4·7H2O and H2SO4 treated chromite ore processing residue (COPR): importance of H+ and SO42- [J]. Journal of Hazardous Materials, 2017, 321(5): 720-727. 许友泽. 铬渣堆场污染土壤微生物修复工艺研究[D].长沙:中南大学,2009. 沈瑜潇. 有机酸协同黄铁矿对Cr(Ⅵ)的还原作用研究[D].南京:南京农业大学,2010. 崔晋艳, 钱天伟, 丁庆伟, 等. 纳米级天然黄铁矿去除水中Cr6+,Cd2+和Pb2+[J].环境工程学报,2016,10(12):7103-7108. 臧磊. 硫精矿处理电镀重金属废水的研究[D].西安:西安建筑科技大学,2008. 王倩. 铁矿石-微生物协同去除水中Cr(Ⅵ)的研究[D].杭州:浙江大学,2010. 傅贤书. 硫化铁处理含铬废水的进一步研究[J]. 西安冶金建筑学院学报, 1988, 20(1): 1-9. 陈永亨, 张平, 梁敏华,等. 黄铁矿对重金属的环境净化属性探讨[J]. 广州大学学报(自然科学版), 2007, 6(4): 23-25. 杨广平, 张胜林, 张林生,等. 含铬废水还原处理的条件及效果研究[J]. 电镀与环保, 2005, 25(2): 38-40. 李喜林, 王来贵, 赵奎,等. 铬渣浸溶Cr(Ⅵ)溶解释放规律研究:以锦州堆场铬渣为例[J]. 地球与环境, 2013, 41(5): 518-523. 鲁安怀. 天然铁的硫化物净化含铬污水的新方法[J]. 地学前缘, 1998, 5(2): 242. 鲁安怀. 矿物法—环境污染治理的第四类方法[J]. 地学前缘, 2005, 12(1): 196-205. BOSTICK B C, FENDORF S. Arsenite sorption on troilite (FeS) and pyrite (FeS2)[J].Geochimica et Cosmochimica Acta, 2003, 67(5): 909-921. LU P, CHEN T, LIU H, et al. Green preparation of nanoporous pyrrhotite by thermal treatment of pyrite as an effective Hg(Ⅱ) adsorbent: performance and mechanism[J]. Minerals, 2019, 9(2):74. 王延明. 铁的硫化矿物对砷的吸附机理研究[D].合肥:合肥工业大学,2012. MACHIDA M, YAMAZAKI R. Role of minerals in carbonaceous adsorbents for removal of Pb(Ⅱ) ions from aqueous solutions [J]. Separation and Purifcation Technology, 2005, 46(1/2):88-94. ERDEM M, OZVERDI A. Kinetics and thermodynamics of Cd(Ⅱ) adsorption onto pyrite and synthetic iron sulphide [J]. Separation and Purification Technology, 2006, 51(3): 240-246. 史亚丹. 煅烧黄铁矿结构演化及其净化水中砷的作用和机理[D].合肥:合肥工业大学,2015. DUAN Y H, HAN D S, BATCHELOR B, et al. Synthesis, characterization, and application of pyrite for removal of mercury [J]. Colloids and Surfaces A: Physicochemical Engineering Aspects, 2016, 490: 326-335. SPRYNSKYY M, BUSZEWSKI B, TERZYK A P, et al. Study of the selection mechanism of heavy metal (Pb2+, Cu2+, Ni2+, and Cd2+) adsorption on clinoptilolite [J]. Journal of Colloid and Interface Science, 2006, 304(1): 21-28. CHANDRA A P, GERSON A R. The mechanisms of pyrite oxidation and leaching: a fundamental perspective[J]. Surface Science Reports, 2010, 65(9): 293-315.
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