Cationic polyacrylamide emulsion with ultra-high concentration as a flocculant for paper mill wastewater treatment

Abstract

Cationic polyacrylamide emulsions prepared with ultra-high concentration (CPAME-uhc) have the advantages of fast dissolution, convenient operation, and low transportation cost. In order to further improve the molecular weight, solubility, and temperature/salt resistance of CPAME-uhc, in this study the preparation process of CPAME-uhc was optimized, and the effects of solubilizing agents and functional monomers on solubility and temperature/ salt resistance of CPAME-uhc were evaluated. Finally, the flocculation performance of CPAME-uhc on papermaking wastewater was examined. The results showed that the molecular weight of CPAME-uhc can be increased to 14 to 15 million by process optimization, and the solubility of CPAME-uhc can be greatly increased by adding urea and Na2SO4. The temperature/salt resistance of CPAME-uhc can be improved by adding 2 wt% N,N-dimethylacrylamide, 2 wt% N-vinylpyrrolidone, and 5 wt% sodium 2-acrylamide-2-methylpropionate, based on the total monomer weight. When CPAME-uhc was added to papermaking wastewater the removal percentages of chemical oxygen demand (COD) and suspended solid (SS) were 95% and 93%, respectively. This study provides a useful reference for the preparation, optimization and application of CPAME-uhc.