混凝过程中铝与聚合铝水解形态的动力学转化及其稳定性

采用Ｆｅｒｒｏｎ逐时络合比色法，并结合电泳测定研究了混凝过程中氯化铝和聚合氯化铝的水解形态动力学转化及稳定性。结果表明，ＡＣ在混凝过程中所形成的水解形态完全不同于ＰＡＣ的预制水解聚合形态，其电荷及分子量均明显低于聚合铝且不稳定，ＡＣ随混凝条件如投加浓度、ＰＨ和混合时间而变，而ＰＡＣ－２５水解聚合形态不随混凝条件变化，始终保持稳定状态，ＡＣ水解沉淀规律与理论计算相符并形成无定形Ａｌ（ＯＨ）３絮体颗粒

DYNAMIC TRANSFORMATION AND STABILITY OF HYDROLYZED ALUM AND POLYALUMINUM IN THE COAGULATION AND FLOCCULATION PROCESSES

Dynamic transformation and stability of alum(AC) and polyaluminum (PAC) in the coagulation and flocculation processes were studied by Al Ferron timed complex colorimetric method and electrophoretic mobility. The results showed that the hydrolyzed species of AC formed in the coagulation and flocculation processes were different from the polymerized species of PAC and their charge and size were lower than those of PAC. The hydrolyzed species of AC were unstable and depended upon the coagulation conditions such as concentration,pH and mixing time. On the contrary,the polymeric species of PAC 25 were relatively stable over pH ranges and the mixing time. Solubility studied showed that AC precipitation are able to be adequately described by amorphous Al(OH) 3 (s) solubility,but PAC 25 was retained upon precipitation and yielded a different network floc particle. It is also demonstrated that the superior Al 13 species did not appeared to be formed in the hydrolysis of alum during coagulation and flocculation processes because some special conditions were required for the formation of the Al 13 species.