修复植物热解半焦中重金属形态分布研究

Study on heavy metal speciation in char from pyrolysis of phytoremediating plants

采用欧盟标准物质局(BCR)连续提取法对修复植物长香谷稻秆热解半焦中重金属元素Cd、Pb、Mn和Cu的赋存形态进行研究。结果表明:(1)用BCR连续提取法分析修复植物热解半焦中Cd、Pb、Mn和Cu的赋存形态是可行和有效的。(2)半焦中Pb、Mn和Cu在900℃时的不稳定态比400℃时分别降低了50.8、38.0、28.5百分点;半焦中Cd在600℃的不稳定态比400℃时降低了11.4百分点。热解温度对于半焦中重金属元素的存在形态有重要的影响。随着热解温度的升高,半焦中可氧化提取态和残渣态Cd和Mn、残渣态Pb和Cu所占比例增大,重金属元素稳定性增强。

The chemical speciation of Cd,Pb,Mn and Cu in char from pyrolysis of phytoremediating plants was studied using BCR（Community Bureau of Reference） sequential extraction procedure.Results showed that the easily soluble fraction and reducible fraction of Pb,Mn and Cu in char produced at 900 ℃ was 50.8%,38.0% and 28.5% lower than that in char produced at 400 ℃,separately;the easily soluble fraction and reducible fraction of Cd in char produced at 600 ℃ was 11.4% lower than that in char produced at 400 ℃;meanwhile,the oxidizable fraction and residue of Cd and Mn were increased with increasing pyrolysis temperature,meaning that these metals were removed from the initial mobile phases to more stable ones.In char produced at high temperature,Cd mainly existed in oxidizable fraction,Pb mainly existed in reducible fraction and residue,and a significant portion of Cu was embodied in the residue.