CMCS-g-PDA的制备及性能研究
Preparation and Performance Study of CMCS-g-PDA

本研究针对壳聚糖基絮凝剂碱性条件下易失活的问题，以羧甲基壳聚糖(CMCS)为主链，通过自由基接枝聚合引入DMC和AA单体，制备了三维网状絮凝剂CMCS-g-PDA。经优化确定最佳合成条件为：50℃、3.5 h、m (CMCS:DMC:AA) = 1:2:2。表征证实单体成功接枝，产物呈海绵状多级孔结构。该絮凝剂在pH 3~11范围内对刚果红、苋菜红与酸性橙G均保持高效去除率(>99%)，碱性性能优于CS-g-PDA，且在混合染料体系中应用潜力良好，为开发宽pH适用、稳定高效的天然高分子絮凝剂提供了新思路。
This study addresses the issue of traditional chitosan-based flocculants being prone to deactivation under alkaline conditions. Using carboxymethyl chitosan (CMCS) as the backbone, a novel flocculant CMCS？g？PDA with a three-dimensional network structure was successfully prepared via free-radical graft polymerization by introducing the cationic monomer methacryloxyethyltrimethyl ammonium chloride (DMC) and acrylic acid (AA). Through single-factor and orthogonal experiments, the optimal synthesis conditions were determined as follows: temperature 50？C, time 3.5 h, and mass ratio CMCS:DMC:AA = 1:2:2. Characterization results confirmed the successful grafting of DMC and AA, and the product exhibited a sponge-like hierarchical porous structure. Flocculation performance tests demonstrated that the flocculant maintains high removal efficiency (>99%) for Congo red, amaranth red, and acid orange G over a wide pH range (3~11), with significantly better performance under alkaline conditions compared to CS？g？PDA. Moreover, it showed promising potential in treating mixed-dye wastewater. This research provides a new approach for developing natural polymer-based flocculants with broad pH applicability, high efficiency, and good stability.