| 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 CODCr 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 CODCr of papermaking wastewater could reach 67.9% when the flocculant dosage was 50 mg/L, pH value was 7.0 at room temperature. |
