Research to synthesize cationic polyacrylamide emulsion use for treatment wastewater drain from the paper-making process ☆

Cationic polyacrylamide emulsions (CPAM) are widely applied in industries such as petroleum extraction, paper-making, cosmetics, and wastewater treatment... Currently, on the market CPAM products are very diverse, depending on the needs of each field the selected products have different characteristics such as molecular weights, and cation content... For paper wastewater treatment, CPAM is required to have a cation content of 30–40% and a molecular weight of 6–12 million Da. There are many studies on synthesizing CPAM, but most of them have been implemented by traditional methods, investigating each factor affecting the polymerization process of CPAM, product characteristics as well as the conversion of a synthesis reaction, none has suggested the simultaneous influence of input parameters. In this study, a new approach to finding the optimizing condition for reaction by using model Box – Behnken in Design Expert software. The obtained regression equations and response surface model could help to find the optimizing input factors for reaction faster, saving research time for developing new products and reducing the production costs compared to traditional methods. Additionally, due to the emulsion having a short storage time, so quick optimization of the synthesis conditions for CPAM production could help manufacturers can localized products to rapidly satisfy market demand instead of waiting for import, sometimes products over pot life due to a long time of transportation. This study obtained copolymers with a molecular weight of 8.042.957 Da, a cation degree of 35.68% with optimal conditions: monomer concentration of 25%, the content of cation monomer of 40.70%, the content of initiator of 0.54%, stirring speed of 2600 rpm, reaction temperature of 61°C, and reaction time of 7 hours. The results of trial testing to treat the wastewater collected from the paper-making process show that the synthetic CPAM has a similar performance compared with imported CPAM on the market. The characterization of CPAM and sludge samples after treatment performed by analysis: FTIR infrared spectroscopy and 1H-NMR magnetic resonance spectroscopy, dynamic light scattering method- DLS, permeation chromatography method gel- GPC, and thermal analysis method TG-DSC. The surface structure of the sludge were analyzed by SEM images.