The Synthesis And Application Of Hydrophobically Modified Cationic Polyacrylamide

Cationic polyacrylamide(CPAM) is an organic polymer flocculant, It has a lot ofadvantages, such as less dosage, better flocculating effects, widely pH range used, lowtoxicity and safe. This article are intended to study and synthetize cationicpolyacrylamide flocculant with better flocculating effects,high molecular weightandhigh solubility in photo-initiator polymerization methodThe hydrophobically modified cationic polyacrylamide were synthesized usingacrylam2ide (AM), acryloyloxyethyltrimethyl ammonium chloride (DAC) andbutylacrylate (BA) under the action of UV irradiation, using the micellar free radicalcopolymerization technique. This paper researched the effect of monomer ratio,proportion between monomers, hydrophobic monomer BA ratio, solubilizer CTAB ratio,initiator concentration, the urea-to-biodiesel ratio and ultraviolet illumination time onthemolecular weight, then obtained optimized synthetizing conditions. The resultsshowed that the polymer with the molecular weight849×104can synthetize when themonomer ratio was30%, the proportion between AM and DAC was70:30, the BA ratiowas2%, the CTAB ratio was2%, the initiator concentration was3‰,theurea-to-biodiesel ratio was2%and the illumination time was100min.The structure of the synthesis product was characterized by infraredspectrometer(FT-IR), the results showed that the polymers was really theterpolymerhydrophobically associating cationic polyacrylamide by the AM、DAC andBA. The scanning electron microscopy(SEM) analysis demonstrated that the surfacemicrostructure of polymerswere excellent and it has the flocculating performance.Thedifferential thermal-thermogravimetric (DTA-TGA) analysis indicated that thestabilityof synthesis product was fine at the normal temperature. The nuclear magneticresonance spectrum(NMR) analysis was proved that the polymers was really theterpolymer hydrophobically associating cationic polyacrylamide again.The self-made products wereapplied for sludge dewatering, The turbidity of thesupernatant and the dry solid content after filtration and dehydration were indicators ofmeasuring the sludge dewatering flocculant performance. The experiment wasinvestigated that the dosage flocculant, the cationic degree, the molecular weight, theeffect of pH were impacted on the effectof sludge dewatering，the results show that theeffect of sludge dewatering was best when the flocculant dosage was40mg/L, the cationic degree was40%, the molecular weightwas7million, the pH was7, theturbidity of the supernatant and the dry solid content were20.8NTU and27.7%.Comparing with three kinds of same type flocculant, the results indicated that the sludgedewatering efficiencies of home-made products was better than Jiangsu、Japanese andZhejiang products, the optimal dosage of the optimal dosage were lower than Jiangsuand Zhejiang products, the optimal dosage of Jiangsu and Zhejiang product were50mg/L, the optimal dosage of Japanese products were the same to home-made products.The self-made products were applied forwaste water containing algae, The wastewater turbidity removal rate and the chlorophyll a removal rate were used to measurethe indicators of self-made products in the effect of algae removal. when the flocculantdosage was3mg/L, the cationic degree was40%, the molecular weight was7million,the pH was8, the algae removal efficiencies of home-made products was best, theturbidity removal rate and the chlorophyll a removal rate were94.1%and99.6%.Compared with different species flocculants dosages on the algae removal efficiencies,the results showed that the algae removal efficiencies of home-made products werebetter than CPAM and PAFS, obviously better than PAFC, the flocculant dosage ofhome-made products and CPAM were significantly less than PAFC and PAFS, theoptimal dosage of CPAM were the same to home-made products, the optimal dosage ofPAFC and PAFS were35mg/L and30mg/L.