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

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.