聚合铝形态分布特征及转化规律

采用多种实验方法,对Al(Ⅲ)的水解—聚合—沉淀反应特征及其转化规律、形态分布及规范分子量大小进行了研究,同时应用X-射线衍射光谱仪和红外光谱仪对聚合铝形态进行了表征。由研究结果似可推断,Al(Ⅲ)水解—聚合过程的形态转化过程为线型→环型→体型。其聚合形态分布取决于翔/铝比值或pH值以及其它因素。在一定羟/铝比值时,聚合铝溶液中可划分为三种类型的形态分布。提出了相应的形态转化模式来表达聚合铝的形态及转化规律。

CHARACTERISTICS OF SPECIES DISTRIBUTION AND TRANSFORMATION OF POLYMERIC ALUMINUM

The hydrolysis-polymerization-precipitation processes of Al(III) were studied by various experimental methods: pH titration, acid depolymeri-zation, timed complex-colorimetric procedure with Ferron-Phenanthroline reagents, ultrafiltration, X-ray diffraction spectrum and infrared absorption spectrum. The results showed that the Al(III) species transformed during the hydrolysis polymerization-processes according to the B= (OH/A1), pH and other factors. By their structure, the species can be divided into three categories of sol-precipitates(Alc), monomeric(Ala) and polymeric(Alb), and the latter may be further divided into three kinds as linear low polymers (Alb1), linear high polymers(Alb2) and high polymers with ring structure (Alb3). The apparent molecular weight graded by ultrafiltration for polymeric species was about 1,000-50,000 and the most of them failed into a range around 10,000. A scheme for chemical speciation model of A1(III)-solution was suggested.