Abstract: A new type composite flocculant PDAC was prepared by in-situ modification of blend composed of acrylamide (AM),microcrystalline cellulose (MCC) and attapulgite by dimethyldiallylammonium chloride (DMDAAC) with 2,2′-azo bis[2-methylpropionamidine] dihydrochloride as initiator.Effects of different reaction conditions on turbidity removal result were examined with artificial prepared kaolin-water suspension as the simulated turbid water for testing.Results show that with the mass of AM as the standard basis,when the initial solid dosage is 20%,the DMDAAC dosage is 40%,the dosage of initiator is 0.3%,acid the activated attapulgite dosage is 60%,MCC is 80%,the reaction temperature is 60 ℃,and the reaction time is 7 h,the flocculation performance of PDAC is better and the turbidity removal rate achieves 96.37%,which is better than that of sample without use of DMDAAC.Further,stability test result shows that the storage stability of PDAC is improved to some extent after the addition of DMDAAC.

Key words: flocculant, polyacrylamide, dimethyldiallylammonium chloride, preparation