摘要
为了评价2%、5%、10%水泥固封镉污染土的处理效果,采用污染物释放实验、低温氮气吸附实验、热重-差热分析实验,检测水泥固封体的Cd2＋浸出浓度、孔隙结构、物质组成与相变规律。未经水泥固封处理的镉污染土,其浸出液中Cd2＋浓度高达9.72 mg/L;当水泥掺量〉5%后,水泥固封体的Cd2＋浸出浓度低于国家标准1 mg/L,说明经水泥固封处理后的镉污染土对污染物的释放具有较好的密封效果。水泥固封镉污染土吸附脱附等温线属于IV型,且存在H3型滞回环。随着水泥掺量的增加,孔径为8-12 nm的孔隙数量增多;总孔容表现出先减少后增大的趋势,且水泥含量为10%时,总孔容达到最大值,其值为0.151 cm3/g。未经水泥固封处理的镉污染土,温度达到1 000℃时,质量损失为12.82%,且存在一个吸热谷;而经水泥固封处理后,水泥固封体的质量损失达到18.6%-31.3%,且在200-450℃之间存在明显放热峰。
To evaluate the solidification effect of Cd-polluted clay containing 2%,5%,10% of cement,the pollutant release test,the low-temperature N2 adsorption test,the TG-DTA test were performed to determine the concentration of Cd（ II） in the leachate,the pore structure,the constitute and phase transformation of the clay solidified by cement,respectively. From the test results,it showed that the Cd（ II） concentration of leachate from Cd-polluted clay was as high as 9. 72 mg/L. For the clay containing more than 5% of cement,the concentration of Cd（ II） in the leachate was smaller than the nation standard value of 1 mg/L,indicating that the cement added into the Cd-polluted clay could significantly weaken the releasing of pollutant. The adsorption isotherm of the Cd-polluted clay solidified by cement belonged to the IV kind,and there existed a H3 kind of hysteresis loop on the curve. With the increase of cement content in the clay,the amount of pores between 8 - 12 nm increased. The total pore volume declined firstly and then increased with the increasing of cement content,and the total pore volume peaked at 0. 151 cm3/ g when the content of cement was 10%. The Cd-polluted clay without cement lost 12. 82% of mass when the heating temperature reached 1 000℃. During the heating procedure,there was an obvious endothermic valley on the curve. For the samples containing cement,the mass loose were18. 6% - 31. 3%. During the heating procedure,there was a significant exothermic peak between 200 - 450℃.
出处
《环境工程学报》
CAS
CSCD
北大核心
2015年第9期4578-4584,共7页
Chinese Journal of Environmental Engineering
基金
住房和城乡建设部研究开发项目(2010-K6-29)
湖北省教育厅科学研究计划项目(D20141703)
国家自然科学基金项目(51474168)
关键词
固化
镉污染黏土
污染物释放
孔隙结构
热效应
solidification
Cd-polluted clay
release of pollutant
pore structure
thermal effect
