【摘要】 采用紫外分光光度法测定了两性高分子螯合絮凝剂(ACPF)与Cu2+、Cd2+、Pb2+、Ni2+形成螯合物的吸收光谱,考察了螯合沉淀物的稳定性,探讨了螯合物的组成,并计算其稳定常数.结果表明,ACPF分别在204、251和285nm处出现最大吸收峰;ACPF中—CSS-基团与Cu2+、Pb2+、Cd2+和Ni2+等离子均按物质的量比2:1形成稳定螯合物,分别在319、310、313.5和326nm处出现最大吸收峰,最大吸收峰发生显著红移.ACPF与Cu2+、Pb2+、Cd2+和Ni2+形成的螯合物的稳定常数分别为1.37×1012、3.26×1011、2.05×1011和3.04×1010.螯合沉淀物中重金属离子的溶出率随溶出液pH值升高而降低.pH≥5.6时,ACPF-Cu2+、ACPF-Ni2+、ACPF-Pb2+和ACPF-Cd2+都很稳定,浸出60d后溶出液中Cu2+、Ni2+、Pb2+和Cd2+浓度都分别低于相应的国家污水综合排放标准(GB8979—1996).更多还原

【Abstract】 The absorption spectra of the Cu2+,Pb2+,Cd2+ and Ni2+ chelates of an amphoteric chelating polymer flocculant(ACPF) were measured via ultraviolet spectrophotometry.The compositions of the chelates were discussed,and their stability constants were calculated.ACPF exhibited three apparent absorption peaks at 204,251,and 285nm.The—CSS-group of ACPF reacted with Cu2+,Pb2+,Cd2+,and Ni2+ in a molar ratio of 2:1 to form the chelates ACPF-Cu2+,ACPF-Ni2+,ACPF-Pb2+,and ACPF-Cd2+,respectively.The maximum absorption peaks of the chelates appeared at 319,310,313.5,and 326 nm,respectively.Compared with the absorption peaks of ACPF,the maximum absorption peaks of the chelates showed significant red shifting.The stability constants of ACPF-Cu2+,ACPF-Ni2+,ACPF-Pb2+,and ACPF-Cd2+ are 1.37×1012,3.26×1011,2.05×1011,and 3.04×1010,respectively.The leaching rate of heavy metal ions from the chelating precipitates decreased with increasing pH.ACPF-Cu2+,ACPF-Ni2+,ACPF-Pb2+,and ACPF-Cd2+ were all very stable at pH≥5.6.The Cu2+,Ni2+,Pb2+,and Cd2+ concentrations in the leach liquors were lower than the corresponding limits specified by the Integrated Wastewater Discharge Standard of China(GB8979—1996).更多还原