The Inverse Emulsion Was Prepared Star P (am-of Dmdaac) Flocculant And Its Application

There were a large number of sludge with much water and many negatively charged particle group during treating municipal sewage. The sludge should be dehydrated for reducing moisture content and volume of sewage sludge. Flocculant was utilized for improving the dewatering performance of sludge for better effects. The copolymer P(AM-DMDAAC) (PDA for short) of acrylamide(AM for short) and dimethyl diallyl ammonium chloride(DMDAAC for short) was concerned widely. Unfortunately, there is a great disparity between our country and foreign countries in some aspects such as production scale, quality and quantity.Many kinds of liner-P(AM-DMDAAC) in the market but few star-P(AM-DMDAAC). So developing a kind of efficient and new P(AM-DMDAAC) has wide application prospectAnd there is unreacted AM which is toxic in polyacrylamide(PAM for short), may lead to its application is limited. So study removing AM from PAM is considered as a important task in the field of developing flocculant.All these facts are the origin and impetuses of this thesis. The main results obtained in this thesis are as follows:Inverse Emulsion polymerization of AM and DMDAAC copolymerization was initiated by heterogeneous redox initiator system, composed of pentaerythritol together with (NH4)2S2O8. The effect of polymerization condition on synthesis was studied via intrinsic viscosity, cationic degree and transform rate and it is the same with that of typical free-radical copolymerization. Star-copolymers (star-P(AM-DMDAAC)) were synthesized and characterized by 1H-NMR. The optimal conditions of copolymerization was attained by single factor experiment and orthogonal test. When the volume ratio of oil to water was 1:1.2, the emulsifier concentration was 10%, the monomer concentration was 35%, the monomer ratio (AM:DMDAAC) was 3:1, the initiator concentration was 2.0%, the reaction temperature was 40℃, the polymerization time was 6h. The copolymer of AM and DMDAAC was prepared by the reaction with characteristic viscosity of 980.25mL·g-1, conversion rate of 98.39% and cationic degree of 21.07 under these conditions.The flocculation performance of star-P(AM-DMDAAC) in sludge dehydration, was investigated by light transmission and sedimentation volume. The effect of intrinsic viscosity, cationic degree, the dosages used, pH and temperature on flocculation efficiency was obtained. It was found that the performance of star-P(AM-DMDAAC) is better than linear-cation-polyacrylamide flocculants. Because chains of star-P(AM-DMDAAC) in solutions are extended and bridging function occurs more easily.The potassium permanganate oxidation method for removing double bonds of AM was studied to achieve reducing the toxicity of AM. Meanwhile, the sludge dewatering effects were researched. And this method was concluded that is feasible and useful. Theoretical support of widely using PAM as flocculation was provided.