多种重金属离子共存下不同钙硅比C-S-H对Pb2+俘获及其稳定性

    Capturing Pb2+ and Its Stability of CSH With Coexistence Multiple Heavy Metals Irons

    • 摘要: 通过溶液法合成不同钙硅比C-S-H凝胶,并借助X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscopy,SEM)、透射电子显微镜(transmission electron microscopy,TEM)、电感耦合等离子发射光谱(inductively coupled plasmaatomic emission spectrometry,ICP-AES)等测试技术,研究了C-S-H凝胶对Pb2+的固化能力及其长期稳定性.研究结果表明:水化液相多种重金属离子共存下C-S-H对Pb2+俘获能力与Pb2+以单一离子存在时有较大差异;且C-S-H钙硅比不同,其对Pb2+俘获机制及俘获能力不同.水化液相中Pb2+的质量分数较低时,C-S-H对Pb2+俘获能力较高;水化液相中Pb2+的质量分数较高时,不同钙硅比C-S-H对Pb2+俘获能力存在明显区别,C-S-H(Ⅰ)对Pb2+俘获能力显著降低;而多种重金属离子共存时,C-S-H对Pb2+俘获能力有所增强.随水化龄期延长(约210 d),不同钙硅比C-S-H对Pb2+俘获能力有不同程度变化.冻融循环作用对低钙硅比C-S-H对Pb2+固化能力有较大影响,且在冻融循环及氯盐侵蚀复合作用下,C-S-H凝胶对Pb2+俘获能力有显著降低.

       

      Abstract: By using solution synthesized method,the ability and long-term stability of CSH gel with different calcium silicon ratio to capture Pb2+ions at the liquid phase hydration with multiple heavy metal ions coexistence were studied by X-ray diffraction analysis,scanning electron microscopy analysis and other analysis method. The research showed that there were big difference at the ability of CSH capture Pb2+between a single ion and multiple heavy metal ions coexist,and the mechanisms and capture Pb2+ability of CSH gel with different calcium silicon ratios were different. When Pb2+content were low at the hydration solution,the ability of CSH gel capture Pb2+were high. While Pb2+content were high at the hydration solution,the capture capability to Pb2 +of CSH( Ⅰ) was significantly reduced,and CSH( Ⅱ)was still high,and the capture capability had been enhanced with multiple heavy metal ions coexistence.With prolonged hydration age( about 210 days),the capture capability of CSH gel to Pb2+changed.Freeze-thaw cycles have a greater impact on the CSH( Ⅰ) capture capability to Pb2+. In the freeze-thawcycles and chloride complexes under the action of erosion,the capabilities of C-S-H gel capturing Pb2+were significantly reduced.

       

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