Preparation And Applications Study Of PDMDAAC

Coagulation is a kind of important water treatment technology. Most of pollutantscan be removed from the water by coagulation. Coagulant is the core of the coagulationprocess, the quality of the coagulant is the key point of coagulation effect and even thewater treatment effect. At present, on one hand, the social demand for available water isincreasing; On the other hand, the available water is declining, wastewater emissionsgrowth, water ingredients and pollutants more and more complex, water treatmentincreased difficulty, the traditional coagulant can’t meet processing requirements.Therefore, the research and development of the new coagulant has become an importantissue in the field of water treatment.PDMDAAC is a kind of water-soluble cationic quaternary ammonium salt. It hashigh coagulation effect, low dosage, wide pH range, and non-toxic, etc, when applied inwater treatment. PDMDAAC can be not only alone used in water treatment as acoagulant; also can be used as a coagulant with other coagulant. And PDMDAAC alsocan be used to synthetic new compound coagulat with other organic or inorganiccoagulat.The scope of this thesis was to investigate the synthesis and application ofPDADMAC as a composite coagulant in wastewater treatment. In this thesis, theaqueous solution polymerization was used in the process of the synthsis, the Taguchimethod was used to design synthetic routes in synthesis and analysis the influence ofthe factors on the intrinsic viscosity of PDMDAAC. The factors in the study weresynthesis temperature, mass of the initiator, volume of de-ionized water and synthesistime. It was found that the combination of factors selected as optimum conditions forsynthesis of PDADMAC were as following: synthesis temperature, mass of the initiator,volume of de-ionized water and synthesis time were70oC,0.1g,10mL and8hrespectively. Under this conditions, the intrinsic viscosity of PDMDAAC was3.45dL/g.The research results show that the synthesis temperature had the most significantinfluence on the turbidity removal efficiency, followed by the volume of de-ionizedwater，the mass of initiator, and synthesis time. Meanwhile, the FTIR and DTA-TGwere used in the characterization and thermo-stability of PDMDAAC.Then, thenew composite coagulant called PFPD was prepared and studied with PDMDAACsynthesized in laboratory and PFS producted in factory.The response surface design(RSM) was used to investigate the influence of the composite scale betweenPDMDAAC and PFS on the coagulation effect.The composite scale were3.5%,7.0%and10.5%respectively. And the prediction model was carried out by RSM. The resultsreveal that for turbidity removal the effectiveness of the coagulants in decreasing orderwas PFS>PFPD1>PFPD2>PFPD3while for COD removal, the order wasPFPD2>PFPD3>PFS>PFPD1.