• 关键词：铝  聚合物  混凝过程  水解动力学  形态转化  稳定性

• 基金项目：国家自然科学基金

• 栾兆坤
• 中国科学院生态环境研究中心环境水化学国家重点实验室, 北京 100085

• 汤鸿霄
• 中国科学院生态环境研究中心环境水化学国家重点实验室, 北京 100085

• 于忱非
• 中国科学院生态环境研究中心环境水化学国家重点实验室, 北京 100085

• 摘要：采用Feron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(AC)和聚合氯化铝(PAC)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，而PAC则与理论计算相悖，延迟沉淀并形成与铝盐不同沉淀特性的网状絮体沉

• Abstract：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 PAC₂₅ 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 PAC₂₅ was retained upon precipitation and yielded a different network floc particle. It is also demonstrated that the superior Al₁₃ 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 Al₁₃ species.

• Key words：alum  polyaluminum  species  transformation  stability  coagulation  flocculation

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