聚硅硫酸铝的形貌结构和絮凝机理

Image and flocculation mechanism of polyaluminum silicate sulfate

以工业水玻璃、工业硫酸铝为原料制得聚硅硫酸铝(PASS)复合絮凝剂,采用电子显微镜观察了不同n(Al)/n(Si)的PASS的形貌,借助倒置式生物显微镜分析了PASS所形成絮体的形貌并用激光粒度分析仪对絮体粒度分布进行了测定,通过红外光谱和X-射线衍射研究了PASS中铝与聚硅酸的相互作用情况,考察了模拟江水中胶体颗粒物和PASS水解物的Zeta电位随pH值的变化,在此基础上探讨分析了PASS的絮凝机理和絮凝过程。结果发现:n(Al)/n(Si)对PASS的形貌有较大影响,絮体粒度分布的数据印证了该结果;红外光谱图表明PASS中有Si—O—Al振动峰出现,峰强度随n(Al)/n(Si)减小而增大;X-射线衍射图证实了聚硅硫酸铝不是晶体,而是铝水解产物与聚硅酸共同作用形成的无定型聚合物;吸附架桥及粘结卷裹作用是PASS絮凝时的主导作用。

Polyaluminum silicate sulfate was prepared with industrial water glass solution and industrial aluminum sulfate as raw materials. Their images of various molar ratio of Al to Si were observed by an electron microscope, while the images of the floccules were studied by inverted biological microscope and the particles size distribution of the floccules were measured by laser particle sizer. And the interaction between polysilicic acid and aluminum was observed by infrared spectrum and X-ray diffraction . The Zeta-potential of colloid contamination and hydrolysate changed by pH value were investigated. On the base of those, the flocculation mechanism and process of PASS are discussed. The results show that the molar ratio of Al/Si affects the images of PASS greatly, which is indicated by the particle size of floccules. The infrared spectrums shows that vibration of Si- O-Al exist, and with the decrease of Al/Si molar ratio, the band intensity increase. The X-ray diffraction proves that PASS is not crystal but the unformed polymer which is chelated by aluminous hydrolysate and polysilicic acid. The bridging and the enwrapping the floccules is the dominate function of coagulation.