环境工程学报2018，Vol.12Issue(3)：893-903,11.DOI:10.12030/j.cjee.201710147
几种硫化物对紫色土汞的稳定化效果及优化稳定条件
Effects of several sulfur compounds on stabilization of mercury in purple soil and appropriate stabilizing conditions
摘要
Abstract
The effects of sulfide species (S,Na2S,FeS,Na2S2O3 and DTCR (sodium dithiocarbamate)) and concentrations on the stabilization mercury (Hg) were discussed in the gray-brown purple soil,which is widely distributed in the Southwest China.The results showed that the five sulfides had significant stabilization effect on Hg in soil.When the elemental S ∶ Hg ratio is 1 ∶ 1,the stabilizing efficiencies followed the order of DTCR＞Na2S＞Na2S2O3＞S＞FeS at Hg concentration ranged from 1.5 to 250 mg·kg-1 in soil.The Hg concentrations in the leachate can reach to a very low level in 3 days after Na2S and DTCR treated,even under the highest Hg contaminated condition.Na2S2O3 showed lower passivation effect on soil Hg,it would take 15 days for the leaching Hg concentration to meet the stabilization criteria at soil Hg concentration of 250 mg·kg-1.S and FeS treatments cannot match the stabilization criteria when soil Hg≥ 150 mg·kg-1.At the constant soil Hg concentration of 150 mg·kg-1,the stabilization effect depends on the amount of sulfides,where DTCR still shows the best performances for the stabilization of soil Hg.Higher S ∶ Hg ratios are needed to reach leaching standard both for Na2S and Na2S2O3 treatments,whereas the further higher dosage will cause the re-dissolution of HgS,and their optimum application rate is 5.It would take more than 7 days to meet the leaching standard both for S and FeS treatments with S ∶ Hg ratio higher than 5.The soil Hg mobility is related to its speciation,and a significant positive correlation exists between exchangeable Hg(Exc-Hg),carbonate bound Hg(Carb-Hg) and the concentration of soil leaching Hg.The high efficiency stabilizer significantly promoted the transformation of exogenous Hg to organic affinity Hg(OM-Hg) and residual Hg(Res-Hg).The concentration Hg in the soil leachate was kept at a very low level within 9 months after soil treated by sulfides,indicating sulfides treatment can meet the requirements of continuous stabilization.关键词
紫色土/汞污染/硫化物/浸出浓度/稳定效率Key words
purple soil/mercury pollution/sulfide/leaching concentration/stabilizing efficiency分类
资源环境引用本文复制引用
陈杰,刘洁,李顺奇,王璐瑶,魏世强..几种硫化物对紫色土汞的稳定化效果及优化稳定条件[J].环境工程学报,2018,12(3):893-903,11.基金项目
重庆市科学技术委员会重点研发计划项目(cstc2017shms-zdyf0036) （cstc2017shms-zdyf0036）
国家重点基础研究发展计划(973)项目(2013CB430003-04) （973）
