共价键型絮凝剂去除水中水杨酸的性能和机理

Performance and mechanism of covalently bounded aluminum-silicon hybrid coagulant( CBHyC) in removing salicylic acid from water

制备了带有季铵基团的共价键型硅铝复合絮凝剂(CBHy C)。通过透射电镜(TEM)表征,与聚合氯化铝絮凝剂(PAC)相比,CBHy C絮凝剂的分子粒径更大。以烧杯实验考察了CBHy C对水中低浓度污染物水杨酸的去除效果和对高岭土标准液的除浊效果。结果表明,CBHy C絮凝剂去除低浓度下SA的混凝效果明显优于PAC,并且絮凝效果随着絮凝剂的投加量、Si/Al摩尔比和碱化度(B值)的增大而提高;CBHy C絮凝剂的除浊效果与PAC相比差别并不明显,且受Si/Al摩尔比和B值的影响不大。通过辛醇-水分配比实验,与PAC和聚合硅酸铝(PASi C)做比较,探讨了CBHy C的作用机理,发现絮凝剂的辛醇-水分配比(Kow)与絮凝剂对SA的混凝效果存在正相关性。

A new covalently bounded aluminum-silicon hybrid coagulant( CBHy C) with quaternary ammonium groups was prepared. The result of transmission electron microscope( TEM) showed that the CBHy C had larger particle size than PAC. The Jar-tests was used to determine the removal of salicylic acid( SA) which is a kind of low concentration contaminants in water and the removal turbidity of Kaolin standard solution. Results showed that the removal efficiency of SA at low concentrations by CBHy C was superior to PAC and the efficiency could be improved by increasing the dosage,Si / Al molar ratio and B value. The removal turbidity of kaolin were little difference between PAC and CBHy C and was slightly affected by Si / Al molar ratio and B value. To explore the mechanism of CBHy C,we did the experiment of the octanol-water partition coefficient. Compared with PAC and PASi C,we found a positive correlation between the distribution ratio( Kow) and the removal efficiency of SA among the three kinds of flocculants.