Distribution and transformation of Al species in organic silicate aluminum hybrid coagulants

In this paper, we discuss three novel organic silicate aluminum hybrid coagulants (HC-T, HC-D and HC-A) developed for the first time using tetraethylorthosilicate (TEOS) and two silane coupling agents – diethoxydimethylsilane (DEDMS) and γ-aminopropylmethyldiethoxysilane (APDES) – as Si sources, respectively. The Al–Ferron complexation timed spectrophotometry was used to investigate the distributions of Al species in these hybrid coagulants. Furthermore, the factors that influence the distribution and transformation of Al species were studied. The experiment results show that the type of silane used and the basicity (B) have significant effects on the distribution of Al species. Alc and Alb are the dominant species in HC-T and HC-A, respectively, because of the different function groups of the silane. The components of Alb in the three hybrid coagulants also vary with the type of silane, and HC-A is inferred to have a homogeneous distribution of Alb species.