Preparation And Application Of Ultraviolet-induced Amphoteric Flocculant P(AM-DAC-AMPS)

Along with the continuous development of social productive forces and the gradual increase in sewage treatment capacity,it has become a focus of public attention to dispose of sludge effectively.To pretreat sludge before fianl treatment can significantly improve economic efficiency.And it is a common chemical pretreatment to add flocculant to the sludge.The amphoteric flocculant contains both anionic and cationic groups at the same time.Not only it has the excellent electrical neutralization and adsorption bridge capacity like traditional cationic flocculants,but also has the advantage of wide dosing range and pH range.So it is necessary to develop a highly adaptable amphoteric flocculant in the face of increasingly complex sludge characteristics.In this paper the amphoteric flocculant P(AM-DAC-AMPS)nitiated by UV are synthesized with acryloyloxyethyltromethylammonium chloride(DAC),2-acrylamide-2-methypropanesulfonic acid(AMPS)and acrylamide(AM),taking V-044 as the innitiator.The factor like total monomer mass fraction,the mass fraction of acrylamide monomer,m(DAC):m(AMPS),dosage of V-044,pH value,UV initiation time are studied in the single-factor experiment,taking the intrinsic viscosity and the conversion rate as the target.The factor like dosage of V-044,pH value and UV initiation time are studied by the response surface analysis to study their effect on the intrinsic viscosity of the final producton.And the optimum preparation conditions are as follows: total mass is 30 g,total monomer mass fraction is 35%,m(AM): m(DAC): m(AMPS)= 80 : 12 : 8,the photoinitiator V-044 concentration is 0.023%,the pH iscontrolled to 5.44,and the irradiation time is 73 min.And the intrinsic viscosity of P(AM-DAC-AMPS)prepared in this optimum preparation conditionsis 1.13 L/g.The polymer product P(AM-DAC-AMPS)is characterized by FT-IR,1H-NMR,scanning electron microscopy(SEM)and differential thermal thermogravimetric analysis(DTA-TGA).The results show that the copolymer has been successfully synthesized with fine porous structure in its surface and it shows good thermal stability.In the sludge dewatering experiment,turbidity,zeta potential,sludge settling velocity,sludge specific resistance and sludge water content are taken as the determination indicators.The experiment results shows that the optimum dosage of P(AM-DAC-AMPS)is 40 mg / L,while the optimum pH is 6-7.For the sludge treated by P(AM-DAC-AMPS),the sludge water content is 74.64%,the sludge specific resistance is 2.76×1012m/kg,supernatant turbidity is about 6NTU.And the resulting dense solid has good settling performance.Compared with homogeneous P(AM-DAC)and commercially available CPAM with similar intrinsic viscosity,P(AM-DAC-AMPS)has the advantage of wider dosing range,better sludge dewatering capacity and better pH adaptability.