Zhao H Z, Yang H W, Guan Y T, Jiang Z P
Department of Environmental Science and Engineering, Tsinghua University, Beijing, China.
Water Sci Technol. 2006;53(7):225-33. doi: 10.2166/wst.2006.227.
The aluminium toxicity is closely related to aluminium species. In this work aluminium was fractionated into seven forms: Al(T), Al(Sus), Al(C + S), Al(S), Al(C), Al(O) and Al(I). Four Al-based coagulants and simulated raw water were used in the laboratory to investigate the aluminium transformation in coagulation, sedimentation and filtration processes. It is the use of Al-based coagulants that contributes more to the increase of the residual aluminium for the low-turbidity raw water, while the Al-based coagulants, especially the polymeric aluminium coagulants, work to remove the aluminium from the high-turbidity raw water. In the case of traditional coagulants, the increase of the turbidity or the dissolved organic carbon (DOC) concentration in the raw water results in a high concentration of Al(C + S). The removal rate of aluminium species in the filtration process is not only related to its size: RAl(Sus) > RAl(C+S), RAl(C) > RAl(S), but also to the physicochemical properties of aluminium species and filter. For the kaolin-polyaluminium chloride system, a lower removal rate of aluminium species results is due to the complexation of humic acid and aluminium species.
铝的毒性与铝的形态密切相关。在本研究中，铝被分为七种形态：总铝（Al(T)）、悬浮态铝（Al(Sus)）、胶体态与溶解态铝（Al(C + S)）、溶解态铝（Al(S)）、胶体态铝（Al(C)）、有机结合态铝（Al(O)）和离子态铝（Al(I)）。在实验室中使用了四种铝基混凝剂和模拟原水，以研究混凝、沉淀和过滤过程中的铝形态转化。对于低浊度原水，铝基混凝剂的使用对残余铝含量的增加贡献更大，而铝基混凝剂，尤其是聚合铝混凝剂，对高浊度原水的铝有去除作用。对于传统混凝剂，原水中浊度或溶解有机碳（DOC）浓度的增加会导致胶体态与溶解态铝（Al(C + S)）浓度升高。过滤过程中铝形态的去除率不仅与其粒径有关：悬浮态铝的去除率（RAl(Sus)）>胶体态与溶解态铝的去除率（RAl(C+S)），胶体态铝的去除率（RAl(C)）>溶解态铝的去除率（RAl(S)），还与铝形态和滤料的物理化学性质有关。对于高岭土 - 聚合氯化铝体系，铝形态去除率较低是由于腐殖酸与铝形态的络合作用。
