Peng Jian-Xiong, Zhao Hua-Zhang
The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
Huan Jing Ke Xue. 2009 Jun 15;30(6):1705-10.
Covalent bonded aluminum-silicon hybrid flocculants were synthesized by employing tetraethylorthosilicate (TEOS) and two silane coupling agents [diethoxydimethylsilane (DEDMS), gamma-aminopropylmethyldiethoxysilane (APDES)] as silicon sources, respectively. The distribution of Al species was investigated by 27Al NMR method and the coagulation behavior was evaluated by treating synthetic water containing humic acid. The results of 27Al NMR show that silicon source, Si/Al molar ratio and basicity (B) exhibit effect on the Al species distribution. In the products with APDES as silicon source, the highest content of Al13 was obtained and its amount increases with the rise of Si/Al molar ratio. The effect of B value on the Al species is similar for the three sets of flocculants. The content of monomeric species decreases with the rise of B value. At Si/Al = 0.4, there are no Al13 observed throughout the B value range in the products with TEOS as silicon source. Al13 starts to appear at a higher B value of 1.5 for the products with DEDMS as silicon source and a lower B value of 0.5 for that with APDES as silicon source, respectively. The coagulation results show that, in acidic conditions, the best dosage range of the flocculants with APDES as silicon source is the widest of the three, resulting in the best coagulation efficiency. In alkaline conditions, the coagulation efficiency of the products with TEOS as silicon source is slightly better than the other two.
分别采用正硅酸乙酯（TEOS）和两种硅烷偶联剂[二乙氧基二甲基硅烷（DEDMS）、γ-氨丙基甲基二乙氧基硅烷（APDES）]作为硅源，合成了共价键合的铝硅混合絮凝剂。通过27Al NMR方法研究了Al物种的分布，并通过处理含腐殖酸的合成水来评估其混凝行为。27Al NMR结果表明，硅源、Si/Al摩尔比和碱度（B）对Al物种分布有影响。以APDES为硅源的产品中，Al13含量最高，且其含量随Si/Al摩尔比的增加而增加。对于三组絮凝剂，B值对Al物种的影响相似。单体物种的含量随B值的增加而降低。在Si/Al = 0.4时，以TEOS为硅源的产品在整个B值范围内均未观察到Al13。以DEDMS为硅源的产品在较高的B值1.5时开始出现Al13，以APDES为硅源的产品在较低的B值0.5时开始出现Al13。混凝结果表明，在酸性条件下，以APDES为硅源的絮凝剂的最佳投加量范围是三者中最宽的，混凝效果最佳。在碱性条件下，以TEOS为硅源的产品的混凝效果略优于其他两种。
