Mg3Al layered double hydroxides (Mg3Al-LDHEPCL) was grafted through free radical polymerization using S2O2-8/S2O2-5 redox initiator.Monomers used for the graft copolymerization were composed of anionic monomers acrylic acid (AA) and sodium acrylate (SA) as well as cationic monomers trimethylallyl ammonium chloride (TMAAC) and dimethyldiallyl ammonium chloride (DMDAAC).The produced hybrid graft copolymer

Mg3Al-LDHEPCL-g-PAA-PSA-co-PTMAAC-co-PDMDAAC

can be used as polyampholyte sewage treatment agent.The graft copolymerization process was monitored by differential scanning calorimetry (DSC) to obtain the kinetic characteristics in the foamed dispersion polymerization system.The graft copolymerization composition was optimized aiming to achieve lower water content in the sludge and lower COD value in the filtrate.The optimized composition was found to be m(Mg3Al-LDHEPCL )∶m(AA+SA+TMAAC+DMDAAC)=0.12∶1;m(TMAAC+DMDAAC)∶m(AA+SA+TMAAC+DMDAAC)=0.288∶0.712

and the neutralization ratio of AA was 18%—24%.Hydrolysis analog studies in 1.0 mol8226;L-1 NaOH solution revealed that the layered cluster of Mg3Al-LDHEPCL hydrolyzed into multiple lamellar segments forming a secondary quaternary ammonium polyampholyte that functioned as coagulation agent.These inherent structural characteristics are important factors for improving the dehydration effect significantly.The crystal structures were characterized by XRD and IR.