Preparation Of Amphoteric Polyacrylamide Latex And Its Performance Research

Amphoteric acrylamide (AmPAM) is a kind of soluble polymer with special molecular structure. Compared with cationic acrylamide and anoinic acrylamide, it has advantages of the above mentioned PAM. Additionally, AmPAM has such merits as anti-polyelectrolyte and wide pH range. It can be used in the fields of exploitation of the oil field, wastewater treatment and paper-making. Therefore, it is very necessary to prepare the AmPAM and to conduct its application research for the national economy development and environmental protect. AM, DMC and AA were chosen as the monomers to prepare the amphoteric polyacrylamide latex (denoted as AmPAM) by inverse phase emulsion polymerization. And the preparation procedures were also optimized. It could be concluded that the optimum conditions of the product included 30% of the monomer dosage, 1.2:1.0 of the mass ratio of oil and water, 1:0.6:0.3 of molar ratio for AM, DMC and AA, 0.8% of the initiator dosage, 10% of the emulsifier dosage, and 50℃ of reaction temperature. The relative molecular mass of the obtained product could reach 5.28×106, the cationic degree could reach 31.2% and the anionic degree could reach 20.3%. The result of infrared spectrum analysis indicated that AmPAM had carboxyl, quaternary ammonium and amido groups, which were the characteristic radicals of the amphoteric polyacrylamide. Sanitary sludge and paper-making sludge were used as dewatered substances to detect the dewatering performance of AmPAM. The result showed that AmPAM had excellent dewatering performance. The optimal dewatering conditions included 12.5 mg/L dosage and 5 of sludge pH. Adding amphoteric polyacrylamide could increase the sedimentation speed. The sedimentation speed was 1.4 times than that of blank sludge in the disposal of sanitary sludge and 1.3 times in the disposal of paper-making sludge. The comparison experiments of dewatering performance indicated that the dewatering performance AmPAM prevailed over those of cationic polyacrylamide CPAM and non-ionic polyacrylamide NPAM in the disposal of sanitary sludge. The moisture content of disposed sludge by AmPAM could be reduced to 93.8%. The dewatering performance AmPAM prevailed over that of non-ionic polyacrylamide NPAM but was not as well as CPAM in the disposal of paper-making sludge. The moisture content of disposed sludge by AmPAM could be reduced to 93.9%. The results of flocculation experiment showed that AmPAM had satisfactory flocculation performance. The optimal flocculation conditions included 12.5 mg/L dosage, 6 of wasterwater pH and 30℃. Compared with other organic high-molecular flocculants, the flocculation performance of AmPAM was better than CPAM and NPAM for the treatment of sanitary wastewater. The luminousness of the disposed water by AmPAM was 98.3% and the maximual removal rate of CODCr could reach 80.2%. For the paper-making wastewater disposal, the flocculation performance of AmPAM exceeded CPAM and NPAM. The luminousness of the disposed water by AmPAM was 89.9% and the maximual removal rate of CODCr could reach 79.8%...