Preparation Of Starch-based Flocculates For Treatment Of Papermaking Waste Water And Study On Their Mechanisms

To utilize plentiful starch resources in our country and meet higher requests of flocculant in the modern wastewater processing, the formation mechanisms of complexes between phosphate ester starch and polyamine(PESPC) were studied, and the functions of the complexes as flocculant in the treatment of de-ink wastewater were investigated. In chapter 2, we studied the preparations of phosphate ester starch and PESPC. The effects of dosages and mass ratios of the phosphates, reaction time and amounts of urea to substitution degree of the phosphate ester starches and reaction efficiency were investigated. And the varieties of chemical properties in PESPC were investigated by UV, IR. In chapter 3, the influences of adding dosages of PESPC, pH of wastewater and flocculating time on the flocculation were investigated, The elimination capacities of PESPC on SS, COD _Cr and turbidity of the de-inked wastewater were also studied and compared to other flocculants. And PESPC at the mass rate of 1:1 showed good flocculating effects. In chapter 4, viscosities of PESPC were studied, and the changes of surface charges on PESPC-1 in the process of flocculation were investigated. The flocculating effects were observed by SEM. The results showed that affinity of PESPC-1 to microfibers was larger than the other flocculants. The flocculating mechanisms of the complexes in the treatment of de-ink wastewater were discussed.