酸雨环境下磷酸镁水泥固化锌污染土溶出特性研究

发布时间：2018-03-05 20:05

本文选题：酸雨　切入点：磷酸镁水泥　出处：《岩土工程学报》2017年04期 　论文类型：期刊论文

【摘要】：通过对磷酸镁水泥(简称MPC)固化锌污染土进行半动态淋滤试验,以研究酸雨作用下重金属的溶出特性,通过更新淋滤液试验组的浸出液电导率和pH的测试来再次印证Zn~(2+)在半动态淋滤试验中的淋滤特性,并添加普通硅酸盐水泥(简称CEMI)固化土试验组进行对比。通过对MPC固化锌污染土半动态淋滤后浸出液中锌离子浓度的测试,分析淋滤液初始pH值、固化剂类型对MPC固化污染土累积锌溶出特性的影响规律。试验结果表明,CEMI组试样累积锌溶出质量大于MPC组试样;初始淋滤液pH=2时的试样表面溶出锌总量普遍高于pH为4和7,而pH=4和7时的试样表面溶出锌总量比较接近;采用更新淋滤液方式的3组试样溶出的Zn~(2+)量均大于不更新淋滤组;氧化镁与磷酸盐的比值(M/P)为6∶1的试样固化效果优于M/P为3∶1的试样。通过试验数据计算分析,得到了有效扩散系数De;锌的De会随酸雨初始pH的下降而增大,淋滤液初始pH=2时的锌的De普遍大于pH=4,7时的De几个数量级。研究结果表明,酸雨作用下影响磷酸镁水泥固化锌污染土溶出特性的主要因素为水泥固化剂的种类以及酸雨的pH值。
[Abstract]:The leaching characteristics of heavy metals in zinc contaminated soil solidified by magnesium phosphate cement (MPC) under acid rain were studied by semi-dynamic leaching test. The leaching characteristics of Zn~(2) in semi-dynamic leaching test were confirmed by the tests of the conductivity and pH of the leaching solution in the test group. The initial pH value of leaching solution was analyzed by measuring the concentration of zinc ion in leaching solution after semi-dynamic leaching of MPC solidified zinc contaminated soil. The effect of curing agent type on the cumulative zinc dissolution characteristics of MPC solidified contaminated soil was studied. The results showed that the cumulative zinc dissolution mass of Cemi group was higher than that of MPC group. The total amount of zinc dissolved on the surface of the sample at pH = 2:00 was generally higher than that of the sample at pH 4 and 7, while the total amount of zinc dissolved on the surface of the sample at pH=4 and 7:00 was similar, and the Zn~(2 of the three groups using the method of renewable leaching filtrate was higher than that of the group without leaching. The solidification effect of the sample whose ratio of magnesium oxide to phosphate is 6: 1 is better than that of the sample with M / P of 3: 1. The effective diffusion coefficient Dex is obtained by calculating and analyzing the experimental data, and the de of zinc increases with the decrease of initial pH of acid rain. The de of zinc at the initial pH = 2:00 is generally larger than that of pH 4, and the de at 7:00 is several orders of magnitude. The results show that the main factors affecting the leaching characteristics of zinc contaminated soil solidified by magnesium phosphate cement under acid rain are the kinds of cement curing agents and the pH value of acid rain.
【作者单位】：浙江工业大学岩土工程研究所;
【基金】：浙江省自然科学基金项目(Y14E080049) 浙江省博士后择优资助课题项目(BSH13020)
【分类号】：X53;X517

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