阳离子高分子絮凝剂HTCC与PAM复配除浊性能研究

Performance of Turbidity Removal by Catonic Polymers Flocculants HTCC Combined with PAM

通过正交试验制备了阳离子高分子絮凝剂壳聚糖季铵盐(HTCC),以高岭土悬浊液的浊度去除率确定了HTCC的最佳投加量,研究了壳聚糖季铵盐与不同分子量聚丙烯酰胺(PAM)的复配除浊效果,确定出其最佳复配比为mHTCC:mPAM=16.67:1,以该复配比在最佳投加量(1.875 mg/L HTCC+0.112 mg/L PAM)下,对原浊为98 NTU的高岭土悬浊液,浊度去除率达到96%以上,余浊<4 NTU。实验表明:先投加HTCC时HTCC/PAM的絮凝效果较先投加PAM时好;pH对HTCC/PAM的除浊效果影响较大,当pH<7时,絮凝效果不太理想,pH约为7.5时除浊效果达到最佳,之后随着pH的升高浊度去除率缓慢降低;沉降时间对HTCC/PAM的除浊效果影响不大,说明沉降速度快;在相同投加范围内,HTCC/PAM最佳投药点的浊度去除率随原浊的增加而增加,余浊亦随原浊的增加而变大;慢搅转速对HTCC/PAM的除浊效果影响较大,且较高的慢搅转速有助于浊度去除率的提高及余浊的降低。

Cationic 2-hydroxypropyl trimethylammonium chloride chitosan （HTCC） was prepared by orthogonal experiment, and the optimum dosage of HTCC for kaolin suspension was determined according to turbidity removal efficiency. Removal rate of the turbidity by HTCC combined with different molecular weight PAM was investigated, and its best composite ratio of HTCC and PAM was determined as 16.67 ： 1. For original water of 98 NTU turbidity, the turbidity removal rate reached above 96% and residual turbidity less than 4 NTU by HTCC/PAM with the composite ratio. Experiment results showed that the flocculation effects of the first dosing HTCC were better than the first dosing PAM. pH has great influence on the turbidity removal efficiency of HTCC/PAM, with the turbidity removal rate not so good when pH lower than 7and the best turbidity removal efficiency obtained when pH near 7.5, and then the turbidity removal efficiency gradually slowed down with increase in pH value. Influence of settling time on turbidity removal is not obvious, indicating settling is very quick. In the same additive scope, both turbidity removal rate and residual turbidity of water sample by HTCC/PAM gradually increase with increase in the original turbidity. Slowly stir speed has great influence on turbidity removal efficiency of HTCC/PAM, and higher slow stir speed contribute to increase turbidity removal efficiency and decrease residual turbidity.