Study On Preparation And Performance Of Sulfonated Poly (Phthalazinone Ether Sulfone) Composite Nanofiltration Membrane

Poly(phthalazinone ether sulfone)(PPES)is an excellent engineering plastic with high-glass transition temperature(305℃),good solubility,hydrophilicity,chemical resistance and mechanical properties.Sulfonated modified not only let PPES become a charged material, but also improve hydrophilic properties of it,so SPPES is an excellent material for preparing good performance and heat resistance nanofiltration membrane.Based on our team previous research,SPPES(D.S.= 0.87)is chose as coating material of composite membrane,by which and PPESK UF membrane,composite nanofiltration membrane is prepared.Studies are focused on components of coating solution and preparation technics.According to experiment results,the best concentration of SPPES of coating film is 5%.The results of solubility parameter method and observation experiment show that mixed EGME and acetone is the better solvent;PEG200 is the ideal organic additive,the quantity of which is about 10%;LiC1 is the better inorganic additive,the quantity of which is below 1%; appending of DMAc enhance the water flux and rejection rate of composite membrane.The performance of composite membrane prepared by glycerin as cross-linking reagent is enhance d obviously,the proper addition is about 30%.About thirty minutes heat-treating at 100℃, the composite membrane obtain that rejection rate is 96%and water flux is 73 L/(m²h).The chemical structure of SPPES composite membrane surface is studied by FT-IR,the membrane pore structure parameters are calculated according to the irreversible thermodynamic model and the electrostatic and steric-hindrance(ES)model.The property of separating different inorganic salt solution is studied.The inorganic electrolytes rejection of SPPES composite membrane ranks:Na₂SO₄＞MgSO₄＞NaCl＞MgCl₂,which is typical characteristics of a negatively charged NF membrane.The water flux has linear increasing trend with pressure increase and the rejection rate tend to be stable when the pressure reaches up to 1.0 Mpa.The composite membrane has excellent pressure resistance.The composite membrane could hold stable membrane separation performance when it was in the 50mg·L ^-1H₂O₂ solution.When the operating temperature is improved from 20℃to 100℃,the water flux enhances more than 4 times and rejection rate decreases a little,which show that SPPES composite membrane has outstanding heat resistance.According to results above,SPPES composite nanofiltration membrane is a kind of excellent performance and heat-resistance composite membrane.