不同重金属离子对C-S-H凝胶影响及其固化稳定性

Research on Effect of Different Heavy Metal Ions on C-S-H Gel and Its Stability

通过溶液法人工合成不同钙硅比C-S-H凝胶,借助XRD,SEM,XPS,TEM,ICP等测试方法,分析研究了C-S-H凝胶对不同种类、不同含量重金属离子(Cr3+,Cr6+,Pb2+,Zn2+,Cd2+等)的俘获能力及其稳定性.结果表明:钙硅比不同,C-S-H凝胶对重金属离子固化稳定性及其固化机制均存在一定差异,高钙硅比C-S-H凝胶对重金属离子固化稳定性较强;重金属离子种类及价态不同,其在C-S-H凝胶中的结合方式及固化能力也不同,其中C-S-H凝胶对Cu2+,Cd2+,Zn2+等离子的固化能力较强,对Cr6+的固化能力较弱.水化液相中,C-S-H凝胶对Cr3+,Pb2+,Zn2+等多种重金属离子的固化能力低于其对单一重金属离子的固化能力;水化液相中Cr6+的存在,会对C-S-H凝胶对Pb2+的固化及其稳定性产生巨大影响,而Cr3+的存在对其影响则较小.

Through solution method to obtain artificially synthesized C-S-H gel with different calcium silicon ratio and by means of XRD,SEM,XPS,TEM,ICP testing methods,the ability and its stability of C-S-H gel to fix heavy metal ions such as Cr^3＋,Cr^6＋,Pb^2＋,Zn^2＋,Cd^2＋ etc.were studied.The research results show that there are some differences in ability of C-S-H gel to fix heavy metal ion and its fixing mechanism with respect to different calcium silicon ratios.The C-S-H gel with high calcium silicon ratio has a higher ability to fix heavy metal ions.Different types and valence of heavy metal ions have different ways of combination with C-S-H gel and fixing ability.C S H gel has stronger ability to fix Cu^2＋,Cd^2＋,Zn^2＋ ions,but quite weaker ability to fix Cr6＋ ion.In the hydration liquid phase,the ability of C-S-H gel to fix multi heavy metal ions is weaker than its ability to fix a single heavy metal ions.At the same time,if there is Cr6＋ ions in hydration liquid phase,the ability of C-S-H gel to fix Pb2＋ ion would be greatly reduced,while Cr3＋ ion has less impact on it.