用于造纸废水处理的季铵型有机絮凝剂的制备

Preparation of a Quaternary Ammonium Polyamine Flocculant Using for Papermaking Wastewater Treatment

关键词:  季铵型有机絮凝剂  COD_Cr去除率  阳离子度  造纸废水

Key Words:quaternary ammonium polyamine flocculants  COD_Cr removal percentage  cationic degree  papermaking wastewater

摘要:以尿素、二甲胺、氨水和环氧氯丙烷为原料，制备了一种季铵型有机高分子聚合物（PEDU），通过红外谱图分析证实了其含有季铵基、羟基等基团。采用正交实验和单因素实验研究了尿素、二甲胺、氨水分别与环氧氯丙烷的摩尔比以及反应温度、反应时间等5个因素对聚合絮凝剂阳离子度和造纸废水COD_Cr去除率的影响。结果表明，PEDU的最佳制备条件为：n(尿素)∶n(二甲胺)∶n(氨水)∶n(环氧氯丙烷)＝0.08∶1.28∶0.30∶1，反应温度为70℃，反应时间为5 h，此时阳离子度为5.49 mmol/g。按以上条件制备出的PEDU作为絮凝剂在常温、pH值7.0、絮凝剂用量50 mg/L的条件下，处理造纸废水，COD_Cr去除率为67.9%。

Abstract:Quaternary ammonium polyamine flocculants, denoted as PEDU, were prepared by polycondensation of urea, dimethylamine, ammonia and epichlorohydrin. The infrared spectrum analysis confirmed that PEDU contained quaternary ammonium group and hydroxyl group. The influences of molar ratios of urea and epichlorohydrin, dimethylamine and epichlorohydrin, ammonia and epichlorohydrin, reaction temperature and reaction time on the cationic degree of the polyamine flocculants and the COD_Cr removal percentage of papermaking wastewater were optimized by the orthogonal and single-factor experiments. The optimum conditions included 0.08∶1.28∶0.30∶1 of the mole ration of urea, dimethylamine, ammonia and epichlorohydrin, 70℃ of the reaction temperature and 5 h of the reaction time. The cationic degree could reach 5.49 mmol/g when the PEDU was prepared at the optimum conditions. The results showed that the removal percentage of COD_Cr of papermaking wastewater could reach 67.9% when the flocculant dosage was 50 mg/L, pH value was 7.0 at room temperature.