Preparation Of GO-PEG Blend Modified PVDF Ultrafiltration Membrane And Its Anti-pollution Performance

Due to excellent chemical stability、heat resistance and good forming membrane property,PVDF had been applied in preparation of ultrafiltration membrane widely.However,PVDF ultrafiltration membrane was easy to form membrane fouling,which wil lead to decrease the water flux of membrane.Graphene oxide and Polyethylene glycol(PEG),as two kinds of hydrophilic modifiers,have been used to modify the hydrophilicity of membranes.The paper research the effect of the GO-PEG composite prepared by esterification between GO and PEG on antifouling of PVDF ultrafiltration membranes.The effect of GO-PEG on the chemical composite and hydrophilicity of membrane surface and pore structure and surface morphology of PVDF membrane were analyzed by using FTIR、contact angle、SEM、AFM test.The results showed that with GO and f-GO concentration increased from Owt%to 1.0wt%,hydrophilicity of membrane surface are enhanced.And after adding f-GO,PVDF membranes obtained better hydrophilicity.The contact angle decreased from 72°to 59°.Base on SEM,the effect of GO and PEG on pore structure of PVDF membranes showed different results.With f-GO concentration increased,pore diameter become bigger firstly,then smaller.For membrane surface roughness,PVDF/f-GO membranes obtained the smallest value for 71.1nm.On the contract,the roughness of virgin PVDF membranes reached to 118nm.With GO-PEG increased from Owt%to 1.0wt%,the pore diameter of membrane increased firstly,than decreased.The water flux exhibit a same tendency.The water flux reach to maximum for being 93 L·m-2·h-1 under additive concentration of 0.5wt%.Besides,the BSA rejection all membranes are not much change and higher than 95%.When the additive concentration of f-GO increased from 0wt%to 1.0wt%,antifouling properties of PVDF membranes showed different influence.For BSA and HA,total and irreversible resistances of PVDF/f-GO membranes were decreased effectively.For BSA and HA fouling,irreversible resistance of PVDF/f-GO membranes was lower by 83.7%、84.4%than one of PVDF membranes.After membrane fouling by BSA and HA,the flux recovery rate(FRR)of PVDF/f-GO membranes obtained the highest value which were 78%、74%by surface cleaning at additive concentration of 0.5wt%.However,the FRR of virgin membranes only reached to be 50%and 47%.According to the result that time dependent flux variation with BSA as pollutant,PVDF/f-GO membranes flux still keep high permeability for BSA solution and water after three circle filtration fouling.And there was almost no decline in the water and BSA solution flux after two circle filtration fouling.The paper also studied the anti-biofouling property of PVDF/f-GO membranes for preudomonas aeruginosa as model pollutant.On the hand,according to biocidal experiment results,the biocidal property of PVDF/f-GO and PVDF/GO membranes was better than PVDF membranes.But PVDF/f-GO membranes didn’t behave better biocidal than PVDF/GO membranes.On the other hand,for anti-biofouling property,PVDF/f-GO membranes decreased the irreversible resistance of membranes effectively.Compared with PVDF membranes,the irreversible resistance of PVDF/f-GO membranes was decreased by 87%for being 0.5wt%adding concentration.Besides,FRR of PVDF/f-GO membranes reached to 80%at additive concentration of 0.5wt%after surface cleaning.However,the FRR of virgin membranes was only 60%which obviously was less than one of PVDF/f-GO membranes.The results indicated that after adding f-GO composite,the hydrophilicity and organic antifouling property PVDF membranes were improved and enhanced.Compared with PVDF/GO,biocidal of PVDF/f-GO membranes wasn’t enhanced.But the anti-biofouling property of PVDF/f-GO membranes was improved compared with PVDF virgin and PVDF/GO membranes.