光聚合纳米壳聚糖/聚丙烯酰胺对源水中PAEs的絮凝研究

Due to extensive use of PAEs, surface source water has been polluted to different degrees. The endocrine and neural interference of PAEs is a serious threat to human health, so it is essential to take effective measures to control PAEs pollution. Because of low concentration in source water, PAEs removal with high efficiency and low cost cannot be achieved by using traditional flocculants. In previous studies, polyacrylamide with better surface property through UV-initiated polymerization was obtained, which resulted in higher removal efficiency of PAEs from water to a certain extend and the main mechanism was adsorption and bridging effect. Polyacrylamide as macromolecule polymer has an excellent bridging capacity. However, its’ insufficient adsorption property is the key factor to restricting removal of PAEs with low concentration in water. In this project, the copolymerization will be realized by adding nano chitosan into the UV initiated polymerization of polyacrylamide, improving adsorption capacity of polyacrylamide flocculants. And the project will conduct a research on the effect and mechanism of UV initiation for the copolymerization. On this foundation, the flocculation performance in PAEs removal from source water by using the synthesized copolymer will also be investigated, and obtain the optimal flocculation conditions with high removal efficiency. The principle of floc formation and flocculation will be finally analyzed in the project. The implementation of this project will provide the theoretical basis for flocculation treatment in water supply, which is significant to guarantee the security of drinking water.

塑化剂邻苯二甲酸酯（PAEs）的大量使用造成地表源水受到不同程度的污染，它的内分泌及神经干扰作用对人体健康构成威胁，加强源水中PAEs的污染控制迫在眉睫。源水中PAEs的含量较低，利用传统的絮凝剂对其处理已无法实现高效去除。前期的研究证实了紫外光引发聚合提高了聚丙烯酰胺絮凝剂的表面性能，一定程度上增加了对水中PAEs的去除效率，且作用机理主要是吸附和架桥。聚丙烯酰胺絮凝剂属于高分子聚合物，具有良好的架桥性能，但其吸附能力不足，是制约对低浓度PAEs高效去除的关键因素。本项目将吸附性能强的纳米壳聚糖引入到紫外光引发聚丙烯酰胺聚合中，通过两者共聚以进一步提高絮凝剂的吸附性能，并研究紫外光引发对共聚反应的影响和机制。在此基础上实施共聚物对源水中PAEs的絮凝去除研究，以期实现高效去除，分析获得絮体形成规律及絮凝机理。本项目的实施对给水絮凝处PAEs提供理论依据，对保障饮用水安全意义重大。

饮用水处理中有机物的去除成为了水质安全的关键问题，混凝水处理技术作为饮用水处理的重要环节在有机物的去除中受到普遍关注。混凝剂是混凝水处理的核心，以聚丙烯酰胺为代表的絮凝剂在水处理中发挥重要作用。开展紫外光引发聚丙烯酰胺的改性制备，以提高传统絮凝剂的吸附性能或电中和性能，获得对源水中有机物高效去除。本项目研究了低压紫外光引发纳米壳聚糖改性聚丙烯酰胺、阳离子改性聚丙烯酰胺絮凝剂的合成，以特性粘度和转化率优化了合成条件，并通过对化学结构与形貌特征的分析讨论了聚合反应机理。以水中邻苯二甲酸二乙酯、腐殖酸、悬浮物等为主要污染物进行了絮凝水处理性能测试与优化，并结合红外光谱、三维荧光光谱、zeta电位、絮体形貌与分形等多方式讨论了絮凝机理。项目研究发现相对于传统热引发、高压紫外光引发聚合的方式，低压紫外光引发聚合能够更高效的促进聚丙烯酰胺絮凝剂的结构改性，具有聚合反应速度快、产物溶解时间短、絮凝性能高等优点。更重要的是，低压紫外光引发由于波长短、功率低，普遍运用于医疗消毒、医药制备等领域，首次引入到絮凝剂制备中来还展现出了更节能降耗、绿色环保、安全无害的优点，有利于产业化应用。通过研究发现通过对絮凝剂吸附性的改性能够提高对源水中低浓度邻苯二甲酸酯的去除，主要絮凝机理吸附性和电中和均能发挥出作用，这为更高效的去除水中痕量有机物提供了有利参考。另外，研究表明水中有机物与悬浮物颗粒有一定程度的相互作用，能够通过吸附等分子间作用力结合在一起。相对于单独有机污染物的絮凝去除，有机物与悬浮物混合水样的絮凝处理中能够以更低的投加量获得更高效的去除率。项目的实施完成计划的研究方案与内容，研究成果发表学术论文10篇，其中SCI收录6篇，申请发明专利2项，其中1项获得授权，达到预期研究目标。