Preparation And Application Of Novel Cationic Polyacrylamide “Water-in-Water” Emulsion

Cationic polyacrylamide?CPAM?"water-in-water"emulsion is used as a flocculant,which has the unique advantages of economy,high efficiency,environmental protection and energy saving.Combining it with magnetic nanomaterials can obtain a novel magnetic flocculant.The effective combination of flocculation technology and magnetic separation technology has greatly improved the flocculation efficiency and has a wide application prospect in the field of water treatment.The research content of this paper is mainly divided into three parts.Part one:Adopting water dispersion polymerization method,using acryloyloxyethyltrimethylammonium chloride?DAC?and acrylamide?AM?as reaction monomers,and polymethacryloyloxyethyltrimethylammonium chloride?PDMC?as Adispersion stabilizer,azobisisobutimidazoline hydrochloride?VA-044?was used as an initiator,and a cationic polyacrylamide?CPAM?"water-in-water"emulsion was synthesized in an aqueous solution of ammonium sulfate??NH₄?₂SO₄?.The structure of the polymer was characterized by infrared spectroscopy?FT-IR?and nuclear magnetic resonance hydrogen spectroscopy?¹H NMR?.The total mass and proportion of monomers,the amount of initiator,the molecular weight and amount of dispersion stabilizer,The influence of factors such as ammonium sulfate concentration on the polymerization reaction,and the optimal synthesis conditions were determined by analyzing the synergistic rules between the influencing factors.The CPAM"water-in-water"emulsion prepared under the optimal synthesis conditions has a relative molecular weight of 3.43×10⁶ to 4.21×10⁶ g·mol^-1,has good fluidity and solubility,and the emulsion stability reaches more than six months.Part two:A novel CPAM"water-in-water"emulsion was synthesized by using water dispersion polymerization method,based on the above-mentioned optimal synthesis conditions,using homemade modified Fe₃O₄ nanoparticles as the third monomer,and introducing it into the polymerization system in the form of magnetic fluid.Using FT-IR,thermogravimetry?TGA?,X-ray diffraction?XRD?,vibrating sample magnetometer?VSM?,and scanning electron microscope?SEM?were used to characterize and analyze the polymer products.The optimal synthesis conditions of modified Fe₃O₄ nanoparticles were determined by discussing the molar ratio of Fe²⁺and Fe³⁺and the amount of silane coupling agent.And the effects of magnetic fluid concentration and ultrasonic time on the fluidity,solubility,stability,and magnetic properties of the polymer product were investigated.The prepared new CPAM"water-in-water"emulsion has a saturation magnetization of 4.23 emu/g,and has good fluidity,solubility and stability.Part three:The kaolin suspension was used to simulate sewage,and the novel CPAM"water-in-water"emulsion was used to perform flocculation experiments.The effects of flocculant dosage,magnetic fluid concentration and ultrasonic time,and sedimentation time on flocculation performance were investigated.At the same time,the flocculation effect of CPAM and novel CPAM was explored through comparative experiments.The results show that the flocculation effect of novel CPAM is better than CPAM under the combined action of external magnetic field and gravity field,and its turbidity removal rate of kaolin suspension can reach more than 98%.