Star Preparation And Application Of The Cationic Polyacrylamide

The type and development of flocculants are summarized.Research actuality of the cationic organic polymer flocculants and the application of diallyl dimethyl ammonium chloride-acrylamide copolymer——PDA are detailed introduced in this paper.In view of development and practical application about organic polymer flocculants all over the world,the flocculation effect of the flocculants is not increase following the molecular weight increase in all areas of water treatment,but is more influence with the molecular structure of the flocculants.Therefore,pentaerythritol-ammonium persulfate as redox initiator,based on the theory of polymerization,propylene amine(AM)and diailyl dimethyl ammonium chloride(DMDAAC)radical polymerization is initiated.A novel structure of the Star cationic poly-acrylamide(star-P(AM-DMDAAC))is synthesized.And the structure of homemade product is characterized by ~1H - NMR.Base the intrinsic viscosity of the solution(and thus calculate the relative viscosity-average molecular weight)and cationic degree of the polymer,the influences of polymerization temperature,initiator,the monomer concentration,monomer ratio,the initial monomer ratio,pH,and urea to the polymerization process were studied,the results showed that the copolymerization process is according to general radical polymerization reaction.A more well reaction is got:1‰of the amount of initiator;35℃of the polymerization temperature;30wt%of monomer concentration;4.5:1 of monomer ratio (AM:DMDAAC);1:2 of the initial ratio(AM:DMDAAC);pH=7.5;and 2wt%of urea by orthogonal test and single experiments,and the product by this polymerization conditions have 418.3 million of the viscosity-average molecular weight and 16.7%of cationic degree,the reaction process conversion ratio reached 98.7%.The test of molecular weight is influenced by dissolving process,the mixing speed, and temperature and so on.The results is that the tested molecular weight are grater change in the different dissolving temperature and the dissolving stirring speed,and stirring speed is over 250r/min,the temperature is higher than 40℃,the tested molecular weight are relatively lesser.But,the stirring speed and temperature of the solution after dissolved may neglect. When testing monomer conversion and cationic degree,the solution concentration should be to less than 50mg/L.In this condition,polymers have reached full extension in aqueous solution and the testing results can reflect the fact well.Using this star structure of the cationic polyacrylamide by homemade treat for activated sludge(moisture content of 99.3%)coming from the Kun-ming fourth sewage plants,and the results is showed that dehydration effect is impacted by the molecular weight,dosage,cationic,pH and temperature,and the storage time of flocculation solution after preparation is a effect to dehydration,and the good storage time is about 5h.Using the experimental product and a commercial line-PDA treat with activated sludge at the best conditions respectively,the results is showed that teatment effect of the star-PDA product is better than that of the commercial linear-PDA.