阳离子型壳聚糖基絮凝剂的制备及其絮凝性能

Preparation of Cationic Chitosan-Based Flocculants and Their Flocculation Performance

通过紫外光引发CTA、DMDAAC和CPCTS三元单体接枝共聚制备CPCTS-g-P(CTA-DMDAAC)絮凝剂,探讨单体浓度、CPCTS与阳离子单体(CTA与DMDAAC)的摩尔比、阳离子度、光照时间对CPCTS-g-P(CTADMDAAC)特性黏度和接枝效率的影响,采用红外光谱、扫描电镜对其结构与组织进行表征,优化其制备和絮凝条件。结果表明:制备CPCTS-g-P(CTA-DMDAAC)的最佳条件为单体质量分数15%~35%、CPCTS与阳离子单体的摩尔比1∶4、阳离子度40%、光照时间120 min;优化制备的CPCTS-g-P(CTA-DMDAAC)特性黏度和接枝效率最高可分别达994.86 mg/L和95.67%;CPCTS、CTA和DMDAAC成功发生接枝共聚反应,共聚物表面有大量多孔或凸起结构,阳离子单体成功接枝到CPCTS骨架上。CPCTS-g-P(CTA-DMDAAC)的絮凝性能优于市售聚丙烯酰胺(CPAM)、聚合硫酸铁(PFS)、聚合氯化铝(PAC),其优化的絮凝条件为投加量4 mg/L,pH为6~9,对浊度的去除率可达90%以上。

The CPCTS-g-P(CTA-DMDAAC)flocculant was prepared by grafting the copolymerization of CTA,DMDAAC and CPCTS monomers via the ultraviolet light.The effects of monomer concentration,the molar ratio of CPCTS and cationic monomer(CTA and DMDAAC),cationic degree and illumination time on the intrinsic viscosity and grafting efficiency of CPCTS-g-P(CTA-DMDAAC)are discussed.Infrared spectroscopy and scanning electron microscopy are used to characterize the structure and organization of copolymers.The preparation and flocculation conditions were optimized.The results showed that the optimum conditions for the preparation of CPCTS-g-P(CTA-DMDAAC)are the monomer mass fraction of 15%~35%,The molar ratio of CPCTS and the cationic monomer was 1∶4,the cationic degree was 40%,and the illumination time was 120 min;The maximum intrinsic viscosity and grafting efficiency are 994.86 mg/L and 95.67%respectively after optimization.The graft copolymerization of CPCTS,CTA and DMDAAC successfully occurred,and there are a large number of porous or convex structures on the surface of the copolymer.Cationic monomers were successfully grafted onto the CPCTS skeleton.The flocculation performance of CPCTS-g-P(CTA-DMDAAC)is better than that of commercial polyacrylamide(CPAM),inorganic flocculants polymer ferric sulfate(PFS)and polymeric aluminum(PAC).The optimized flocculation conditions are as follows:the dosage is 4 mg/L,the pH is 6~9,and the removal rate of turbidity can be up to more than 90%.