High mercury leachate containing HgS22- complex ion： Detoxifying solidification and high efficiency Hg extraction

作     者：Guanghua Lu Changsheng Yue Guibo Qiu Min Guo Fangqin Cheng Mei Zhang 

作者机构：School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Central Research Institute of Building and Construction Co. Ltd. MCC Group Beijing 100088 China Shanxi Collaborative Innovation Center of High Value-added Utilization of Coal-related Wastes in Shanxi University Taiyuan 030006 China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2018年第30卷第11期

页      面：177-184页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 

基　　金：supported by the National Natural Science Foundation of China(Nos.51672025,51572020,51372019) Major Projects of Science and Technology in Shanxi Province(No.MC2016-03) 

主　　题：High mercury leachate Cement solidification Mercury extraction Cleaning and efficiency 

摘      要：Clean and efficient treatment of high-mercury leachate produced from remediation of mercury-polluted soil has become a huge challenge for environmental scientists. In this work, cement solidification was firstly adopted to treat the high-concentration mercury leachate, which had high alkalinity. Different mercury concentrations, namely 3.120 mg/L Hg mercury leachate and 9.243 mg/L Hg mercury concentrated leachate, were separately solidified by Portland cement. The results indicated that simply using the cement can properly solidify both the leachates to meet the waste landfill standard, with liquid （mL）/solid （g） ratio （US ratio） of 4：10-6：10. In order to make full use of mercury in the leachates, a Hg extraction method was subsequently carried out under different experimental parameters, such as temperature and pH value. It was shown that the Hg extraction ratio could reach as high as 99.84% and almost all the mercury in the leachate could be transformed to HgS precipitate; moreover, the Hg concentration in the treated leachate was reduced from 3.120 to 0.005 mg/L at pH 2.98 and 30℃, which was much less than the limit of the national standard, indicating that the leachate had been completely cleaned and could be discharged freely. Hence, simple cement solidification renders high-mercury leachate nontoxic, and the Hg extraction method can successfully recover the Hg and enable the residual leachate to be discharged safely.