Study On Hydrophilic Modified Polyphenylene Sulfide Membrane And Its Performance

With the development of human society,the shortage of water resources is becoming more and more obvious.The key method to solve this problem is to recycle the water resources.There are many shortcomings in traditional water treatment methods.Membrane separation technology is a new technology which developed rapidly in the field of water treatment in recent years.Compared with traditional treatment methods,it has many advantages,such as simple operation,safety,pollution-fi-fee,low energy consumption and high separation efficiency.However,under extreme conditions such as strong acid,strong base and polar solvent,the membrane structure of conventional materials can be easily destroyed.Polyphenylene sulfide(PPS)is a kind of material with acid and alkali resistance,solvent resistance and thermal stability.The prepared PPS membrane can be used in harsh environment.However,the hydrophilicity of PPS membranes is poor,which is easy to be polluted and the separation efficiency is not high.These disadvantages restrict the application of PPS membranes.Therefore,the hydrophilic modification of PPS membrane is needed to improve its wettability,anti-pollution and other properties.Firstly,hydrophilic modification of PPS membranes was carried out by chemical method.The PPS membranes were oxidized by hydrogen peroxide(H2O2),acetic acid(CH3COOH)and sulfuric acid(H2SO4)to prepare PPS/PPSS composite membranes.After modification,sulfonyl groups(-SO2-)were introduced into membrane surface,then a composite membrane with both PPS support and PPSS outer-layer was obtained,and the prepared com-posited membrane were characterized by FT-IR,XPS,XRD and SEM to confirm the structure and chemical composition.Compared with PPS membrane,the composite membrane had better hydrophilic ity,anti-fouling performance and pure water flux.Furthermore,the dyes rejection property of composite membrane was studied and the separation efficiencies were more than 94%for both Methyl blue and Congo red.The composite membranes also maintain excellent solvent resistance of PPS membranes and can be used in extreme environments.Secondly,the hydrophilic modification of PPS membrane was carried out by surface coating method.The PPS membrane was treated by catechol(CA),polyethyleneimine(PEI)and 3-Glycidoxypropyltrimethoxysilane(KH560).Michael addition or Schiff base cross-linking reactions were carried out between CA and PEI to form a coating on the surface of the membrane.The super-hydrophilic CA/PEI/KH560-PPS membrane was prepared by covalent bond reaction between KH560 and primary amino group.The surface mineralization ofKH560 makes the modified membrane keep good stability in strong acid and weak alkali environment.In the anti-fouling test,the modified membranes showed excellent anti-fouling performance,which was due to the superhydrophilic surface of the modified membranes.In the dye interception performance test of Rhodamine B and methyl blue,the modified membrane showed excellent dye interception performance(>99%),which was the result of steric hindrance effect,Donnan effect and intermolecular interaction.