Study On The Preparation, Characterization And Properties Of Cationic Flocculating Agent

With the increasing scarcity and pollution of water, people paid more and more attention to thedevelopment of the water treatment flocculants. Cationic polymeric flocculants have been used in almost all kind of water treatment. Cationic polyacrylamide(CPAM) aqueous dispersion emulsion has unique virtues, such as high efficiency, energy saving, environmental protection, convenient and low cost. As a new kind of flocculant, CPAM became a research hotspot in recent years.Cationic-polyacrylamide dispersions were prepared by dispersion polymerization in Ethanol/Water and Ammonium sulphate/water solution, using acrylamide(AM) and 2-methylacryloylxyethyl trimethyl ammonium chloride(DMC) as monomers,2,2-azobis-(2-methylpropionconidine) dihydrochloride (V-50) as initiator.Dispersion copolymerization of acrylamide with cationic monomer was reacted in ethanol/water medium by using polyvinyJpyrroidone(PVP) as dispersion stabilizer. The influence of the reaction such as the ratio of ethanol to water, the dosage of PVP, polymerization temperature to the performance of the dispersion copolymerization were investigated, by means of determination the solid and the content viscosity of product and observation fluidity and longterm stability. The structure and relative molecular weight of CPAM were determined by FTIR and Ubbelohde viscometry. The best condition of dispersion copolymerization is that the ethanol concentration is 50-60%(V), the reaction temperature is 50℃, the dos of PVP on monomer mass is 8-10%(wt). The obtained CPAM aqueous dispersion emulsion has good liquidity, and bad longterm stability.Using inorganic salt ammonium sulfate((NH4)2SO4) solution instead of organic solvents as reaction medium, the CPAM aqueous dispersion emulsion was successfully prepared by dispersion polymerization in the role of dispersing stabilizer poly(acryloylxyethyl trimethyl ammonium chloride)(PDAC). The effects of (NH4)2SO4 concentration, PDMC content, the amount of cationic monomer, V-50 content on the dispersion polymerization were discussed systematically. The optimized synthesis conditions were achieved. The structure of CPAM were characterized by FTIR, the relative molecular weight were determined by Ubbelohde viscometry. Resulta show that the obtained CPAM aqueous dispersion emulsion had good liquidity and stability. The relative molecular weight of CPAM is as high as 180×104 g/mol.The contrast experiment of flocculating properties between the home-made cationic poly-acrylamide products and manufacturer sample was investigated. The visible UV spectrophotometer and the removal rate of COD is utilized to measure its superstratum transmittance of the treated wastewater. The results showed that the molecular weight and dosage of flocculant is very important, the bigger the molecular weight and dosage, the better effection of flocculation. As the molecular weight of home-made is too low, the effection is not good,Improved experiments should be done later.