新型两性壳聚糖絮凝剂的合成及其絮凝效果的研究

Synthesis of Novel Amphoteric Chitosans as Flocculants and Research on the Flocculation

该研究旨在通过化学修饰壳聚糖提高其污水处理的絮凝效果。通过壳聚糖的氨基与甲醛和酚类物质的曼尼希反应引入硫酸根基团,制备了3种具有不同取代度的两性壳聚糖衍生物。红外及核磁谱图分析结果证实,合成产物中具有苯并噁嗪环结构。经处理高岭土的水悬浮液进行模拟絮凝实验发现,这3种苯并噁嗪壳聚糖衍生物的絮凝效果随絮凝剂用量、污水pH和离子强度等条件变化而有较大变化,并均可在适当絮凝条件下获得最佳值。它们的絮凝效果全面优于未经处理的壳聚糖对比样品。取代度为80%左右的硫酸化壳聚糖絮凝剂处理污水可达近100%的浊度净化率。

This study focused on chemical modification of chitosan to improve its flocculation effects in wastewater treatment process. Based on Mannichi-type reaction of the amino groups of chitosan, formaldehyde and phenolic compound, sulfonic groups were introduced into chitosan and three kinds of amphoteric chitosan derivatives with different degree of substitution of sulfate groups were prepared. IR and NMR spectra confirmed that the new chitosan derivatives have a benzoxazine structure. For removal of turbidity from kaolin suspensions, the flocculation effect of the products varies with dosage, pH and ionic strength, and an optimum value can be obtained in an appropriate flocculation condition. The flocculation effect of the modified chitosans is much better than that of the chitosan controls. The turbidity removal rate reached to about 100% when the sulfated chitosan with DS of 0.8 was used.