Effects of Ca on the distribution,structure and morphology of aluminum species in polyaluminum chloride

The flocculation efficiency of polyaluminum chloride (PAC) is closely related to the distribution and structure of its Al species, and Al13 is the optimal species in PAC for fiocculation. A series of PAC containing Ca was prepared by adding Ca before and after the basifying reaction. The effects of Ca on the Al species were studied by 27Al nuclear magnetic resonance (NMR) and atomic force microscope (AFM) techniques. The experimental results show that the introduction of Ca increases the content of Aim and Al13 in PAC and decreases their chemical shifts in NMR spectra due to the electric repulsion between the positive Ca species and Al species and the formation of Al-O-Ca complexes.With the rise of Ca/AI molar ratio, the Al species in PAC tend to scatter. It is observed that the formerly branch-aggregated clusters are tending to form granule-aggregated ones whose diameter gets smaller and smaller, and the fioccule aggregates are formed at a higher Ca/Al molar ratio. The introduction of Ca to PAC, which increases the Al13 content, is certainly to enhance the fiocculation efficiency of PAC in water treatment.

作 者： ZHAO Huazhang GE Xiaopeng LUAN Zhaokun JIANG Zhanpeng   作者單位： ZHAO Huazhang,JIANG Zhanpeng(Department of Environmental Science and Engineering, Tsinghua Un iversity, Beijing 100084, China)

GE Xiaopeng,LUAN Zhaokun(State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China) 

刊 名： 科學通報(英文版)  SCI 英文刊名： CHINESE SCIENCE BULLETIN  年，卷(期)： 2004 49(12)  分類號： P5  關鍵詞： AI13 species   distribution of Al species   structure and morphology   polyaluminum chloride containing Ca  

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