Polydimethyl Diallyl Ammonium Chloride And Applied Research In Water Treatment

Polydiallyldimethylammonium chloride (PDMDAAC) is a kind of cationic organichigh-molecular compound. As a kind of flocculating agent, PDMDAAC is water miscible,highly effective and with low mammalian toxicity. In this paper, Polymerization ofDMDAAC was initiated by new type complex initators, and compounded with polyferricsulfate (PFS) to prepare composite flocculants. The application properties of compositeflocculants were studied systematically.Diallyldimethylammonium chloride (DMDAAC) was prepared by one-step method.The productive rate of DMDAAC is up to 88.59%(count by allyl chloride) when thetemperature of preparing dimethylallylamine is 15℃～25℃, n(dimethylamine):n(allylchloride): n(NaOH) is 1:1.2:1, the reaction temperature of preparing DMDAAC is 45℃,the reaction time is 6hr, and n(allyl chloride e):n (dimethylamin) is 0.95:1. The impurityand NaCl which may be harmful to polymerization can be removed effectively byvacuum distillation.Polymerization of DMDAAC was initiated by complex initators of ammoniumpersulfate-triethanolamine (APS-TEA). The conversion rate of DMDAAC is up to80.3%, and the intrinsic viscosity of PDMDAAC is 1.01dl·g^-1 when 0.137g ammoniumpersulfate (APS), 0.088g triethanolamine (TEA) and 3.76mg EDTA·2Na are added into25ml PDMDAAC solution of 72% (mass concentration), the polymerization temperatureis 42℃and the polymerization time is 24hr. Compared with polymerization initiated byAPS, the polymerization temperature of polymerization initiated by APS-TEA is lowerand the intrinsic viscosity of PDMDAAC is higher. The copolymerization kineticequations of DMDAAC is: R_p=kC_M^0.9344 ((C_APS·C_TEA)^1.8703The corresponding apparent polymerization activation energy is 52.633kJ/mol.The active sludge which sludge specific resistance is 2.68×10¹²m·kg^-1, rate ofwater content is 98.7% was treated by flocculation. The sludge specific resistancewere separately 0.44×10¹²m·kg^-1, 0.54×10¹²m·kg^-11, 0.50×10¹²m·kg^-1, 0.52×10¹²m·kg⁽-1and 0.42×10¹²2m·kg^-1 after the active sludge was treated by PFS, PPFS, PDMDAAC,PFS-PDMDAAC and PPFS-PDMDAAC separately when dosage were proper. Thedehydrating rates were over 90%.The municipal wastewater in which turbidity is 35.0mg/L, COD is 164.4mg·L^-1was treated by PFS, PPFS, PFS-PDMDAAC and PPFS-PDMDAAC separately when dosage were proper. The removal rates of turbidity and COD were respectively 88.0%and 64.3% after the wastewater was treated by PFS; The removal rates of turbidity andCOD were respectively 84.0% and 66.4% after the wastewater was treated byPFS-PDMDAAC; The removal rates of turbidity and COD were respectively up to 97.7%and 74.9% after the wastewater was treated by PPFS; The removal rates of turbidity andCOD were respectively 98.5% and 83.4% after the wastewater was treated byPPFS-PDMDAAC.The municipal wastewater in which concentration of bacillus coli is 10×10⁶/mLwas treated by by flocculation. The removal rates of bacillus coli were separately 46.2%,63.9%, 68.5% and 84.0% after the wastewater was treated by PFS, PFS-PDMDAAC,PPFS and PPFS-PDMDAAC separately when dosage were proper.The simulated printing and dyeing wastewater were treated by flocculation. Theremoval rates of absorbance were separately 19.6%, 95.2%, 97.8%, 58.51%, 87.58%,95.71%, 86.41% and 66.12% after the wastewater in which concentration of AcidBlue 7 is 30mg·L^-1 was treated by PFS, FeSO₄, PFS-FeSO₄, PFS-PDMDAAC,FeSO4-PDMDAAC, PFS-FeSO₄-PDMDAAC, PPFS and PPFS-PDMDAAC separatelywhen dosage were proper; When the simulated wastewater in which concentration ofDirect Scarlet 4BS is 30mg·L^-1 was treated by above-mentioned flocculationsseparately, the removal rates of absorbance were up to 83%-89%; When the simulatedwastewater in which concentration of Apollo direct Brown 3G is 120mg·L^-1 wastreated by above-mentioned flocculations separately, the removal rates of absorbancewere 44%-66%. When the wastewater in which concentration of Rhodamine B extrais 10mg·L^-1was treated by above-mentioned flocculations separately, the removal ratesofabsorbance were very low. The removal rates ofabsorbance was up to 96.2% afterthe Rhodamine wastewater was treated by FeSO₄ and H₂O₂ was added; The removalrates of absorbance was up to 95.6% after the Rhodamine wastewater was treated byPFS-FeSO₄-PDMDAAC with H₂O₂ and PAM were added.