采用烧杯混凝实验和Zeta电位研究了羧甲基壳聚糖(CMCS)对高岭土模拟水样的混凝特性,考察了水力条件、pH值、混凝剂投加量和原水浊度对混凝性能的影响。结果表明,混凝效果受悬浊液pH值、原水浊度和CMCS投加量的影响较为明显,而水力条件的差异对混凝效果的影响不明显。达到最佳混凝效果所需CMCS投加量随pH值增加而增加,随原水浊度的增加而减少。而在最佳CMCS投加量时,浊度去除率随着原水浊度的降低而降低。高岭土悬浊液pH为5、CMCS投加量在0.1~5.0 mg/L的范围内时混凝效果较佳,沉降15 min后剩余浊度降至10 NTU以下,去除率达到95%。吸附架桥和电性中和是CMCS的主要混凝作用机理,混凝反应条件不同时,起主导作用的混凝机理不同,CMCS对高岭土的混凝是多种机制共同作用的动态变化过程。
A bench scale experiment on the flocculation properties of amphoteric carboxymethyl chitosan(CMCS) was described,in which kaolinite suspension was tested using jar test and zeta potential studies. The results indicated that the effect of hydraulic condition was limited on turbidity removal,while factors such as pH value,initial turbidity and dosage of CMCS remarkably affected the turbidity removal. It was showed the removal rate could reach up to 95% in the optimized condition. Furthermore,mechanism of flocculation was discussed based on the zeta potential measurement,which suggested that flocculation process induced by CMCS was dominated by charge neutralization and bridging,and flocculation was also a dynamic process acted upon by both of charge neutralization and bridging.