Photo-initiation Synthesis, Characterization And Application Of Cationic Polyacrylamide

With the rapid development of China’s urbanization, the urban sewage hasincreased dramatically, which makes a shortage of water resources even more tense.Therefore, sewage treatment is urgently needed. Whereas, as one of the wastewatertreatment technology used widely now——flocculation and sedimentation method, thetype and nature of flocculant directly determines the effect of flocculation. As anorganic polymer flocculant, although the traditional synthesis process of cationicpolyacrylamide is more mature, there are still some defects such as the unstable productquality and the high cost. So the research on the new synthesis method and the highcomprehensive performance of flocculant has a great significance. This article aims tostudy and synthetize cationic polyacrylamide flocculant with high molecular weight,high solubility, low residual monomer content and optimum flocculation effect inphoto-initiator polymerization method.In this research, Cationic polyacrylamide(CPAM) was synthesized by the monomerof acrylamide(AM) and acryloyloxyethyltrimethyl ammonium chloride(DAC) with a365nm give priority to wave of high-pressure mercury lamp, using photo-initiationpolymerization method. The optimization synthesis experiment results of cationicpolyacrylamide showed that the molecular weight of CPAM can be achieved to9million when organic azo initiator concentrations A is5‰, the gross mass fraction ofmonomer is30%, cationic degree is40%, the amount of solubilizer B is4‰, and thepolymerization reaction time is1h with a pH value of5.The structure of the polymers was characterized by infrared spectra analysis, theresults showed that the synthesis product was indeed the copolymer CPAM by the AMand DAC. DTA-TGA analysis revealed that the self-made cationic polyacrylamide wasstable at the normal temperature. UV-visible spectra analysis proved that thepolymerization between the monomer actually took place, synthesis of the newsubstances CPAM. The scanning electron microscopy(SEM) analysis results of themorphology structure of the self-made CPAM showed that adsorption bridging abilityand flocculation performance of the self-made cationic polyacrylamide were increased.The unreacted acrylamide was extracted first by the mixture of ethanol and water,and determined by UV spectrophotometry. In addition, the influence of the reaction time,organic azo initiator A, cationic degree, the solubilizer B and complexing agent EDTA on the residual AM content of polymerization product was studied. The results showedthat when prolonging the reaction time to60min, the residual monomer content ofCPAM can be reduced to0.21%; When organic azo initiator A dosage for5‰andcationic degrees for40%, the residual monomer content of polymers was the lowest;The solubilizer B had a certain effect on the residual monomer content of polymers; Theinfluence of complexing agent EDTA on the residue AM content of polymers was sosmall that can be ignored.The self-made products were used for sludge dewatering experimental research.The experiments showed that the best sludge dewatering result can be achieved whenthe molecular weight being8million, cationic degree being40%and the optimaldosage being30mL, and the water ratio of filter was82.2%, the filtrate turbidity was1.41NTU. In addition, the sludge dewatering effects contrast experiment between theself-made product and the three common flocculants used in domestic sewage treatmentplant was made, the results showed that the sludge dewatering effect of the self-madeproducts was better than that of Shandong products, slightly better than that of theJiangsu products and the Japanese products.