PATS的制备表征及其处理低浊水效能与残留铝控制

Preparation and characterization of PATS and its effect of coagulation and control of residual aluminum on low-turbidity water treatment

以水玻璃、硫酸铝和硫酸钛为原料,采用共聚法制备了聚硅酸硫酸铝钛(PATS)混凝剂。考察了混凝剂处理模拟低浊水的效能和出水残留铝含量,并且运用FTIR、XRD和SEM对混凝剂的结构形貌进行了表征。研究发现,当Al/Ti摩尔比为10∶1,(Al+Ti)/Si摩尔比为1∶2,水体pH为7~9,水体温度为10℃时,合成的PATS混凝剂对模拟低浊水的混凝性能最好,残留铝含量较低,当该混凝剂投量为0.10 mmol·L^(-1)(以金属离子计)时,余浊和残留铝含量分别可达到0.36 NTU和0.022 mg·L^(-1)。结果表明,PATS中存在铝、钛及其水解产物与硅发生相互作用生成的Al—O—Si键和Ti—O—Si键。PATS不是几种原料的简单混合,而是一种无定形共聚物。与聚合氯化铝、聚硅酸硫酸铝相比,PATS具有更好的混凝效果和更低的残留铝含量。

Poly-aluminum-titanium-silicate-sulfate（ PATS） coagulant was prepared by copolymerization using sodium silicate,aluminum sulfate,and titanium sulfate. The effect of PATS on coagulation and content of residual aluminum was investigated by simulated low-turbidity water treatment. Moreover,the structure and morphology of the prepared PATS was characterized by FTIR,XRD,and SEM. It was found that the synthetic PATS showed the best coagulating effect and lower residual aluminum content in treated water under the following experimental conditions： n（ Al）/n（ Ti） at 10 ∶ 1,n（ Al ＋ Ti）/n（ Si） at 1 ∶ 2,initial pH 7 to 9,water temperature 10 ℃. The residual turbidity and content of the residual aluminum reached 0. 36 NTU and 0. 02 mg · L^-1,respectively,when the dose of the resultant PATS was adjusted to 0. 10 mmol·L^-1（ based on weight of the metal ion）. Results showed that Al—O—Si bonds and Ti—O—Si bonds could be formed by the interaction between aluminum and titanium ions,as well as their hydrating polymers and poly-silicic acid. The PATS coagulant is an amorphous polymer rather than a mere mixture of raw materials. Self-made PATS has better coagulating effect and lower residual aluminum content in treated water,than poly-aluminum-silicate-sulfate（ PASS） and PAC have.