Study On Synthesis Of Cationic Starch Flocculant In Aqueous Two-Phase System

Flocculation is the most widely adopted role in wastewater treatment. The most important is that a flocculant is prepared with excellent performance and widely used. In the dissertation, based on the study of aqueous two-phase diagram of P(ST-AM)-PEG-H2O, a high-performance cationic starch flocculant is synthesized in aqueous two-phase system.To PEG solution as continuous phase, the phase behavior of aqueous two-phase system was studied. The impact of different P(ST-AM) molecular weight, PEG molecular weight, PEG concentration and temperature on the phase diagram was visited. The results showed that the P (ST-AM) characteristic viscosity for328.25, the PEG molecular mass for20,000, the PEG concentration for20%, the temperature is50℃, the system reached the lowest split phase concentration; Study impact of different factors with partition coefficient of acrylamide(AM) and diallyldimethylammonium chloride(DMDAAC). The results show that, when the concentration of PEG20000is10%, the partition coefficient of AM and DMDAAC reaches the max. When the P (ST-AM) concentration is5%, the partition coefficient of AM down to lowest. When the temperature is50℃, the partition coefficient of AM and DMDAAC reaches the max.Based on the study of aqueous two-phase diagram of P(ST-AM)-PEG-H2O, a starch graft polymer starch-graft-acrylamide-diallyldimethylammonium chloride is synthesized in aqueous two-phase system. The best reaction conditions are confirmed by the orthogonal test. The initial monomer concentration is15%, PEG20000concentration is10%, initiator concentration is0.1%, m(ST):m(AM+DMDAAC)=3:7, m(AM):m(DMDAAC)=7:3, T=50℃,t=6h, m[(NH4)2S2O8]:m[CO(NH2)2]=1:3, The results showed that P(ST-AM-DMDAAC) characteristic viscosity761.5mg/L, grafting ratio227.4%, grafting efficiency97.6%, monomer conversion98.5%.The structure of product was analyzed and characterized by IR.