| In this paper,hydrophilic metal nanoparticle-GO / F127 / PVDF composite modified membranes with high-efficiency catalytic reduction ability for printing and dyeing wastewater were prepared based on functional metal / metal oxide nanoparticle,two-dimensional planar structure graphene oxide(GO)and amphiphilic polymer F127.Graphene oxide(GO)with a large specific surface area was used as a carrier,and metallic silver nanoparticles were loaded to prepare a GO-Ag / PVDF / F127 modified membrane.Based on the principle of non-solvent induced phase separation(NIPS)method,isopropanol(IPA)is used as a coagulation bath.The speed of phase separation is controlled by adjusting its concentration.The SEM image showed that the GO-Ag / PVDF / F127 modified membrane prepared in 50% IPA coagulation bath had a well-distributed sponge-like pore morphology.In addition,the composition and surface roughness of the modified membrane were proved by XRD,FTIR and AFM.Through a series of performance tests such as dynamic contact angle,pure water flux,BSA pollutant retention,backwash flux,and tensile strength,the hydrophilicity,permeability,anti-pollution ability,and mechanical properties of the membrane were evaluated.The results show that the performance of the membrane MPGOAg-50% is the best,the pure water flux is 87.10 L ? m-2 ? h-1,the BSA rejection rate is 94.7%,and the contact angle is 70o.Modified membranes prepared from monovalent metals or metal oxides have certain functional limitations.Primitive zinc oxide(Zn O)was a wide bandgap(3.37 e V)semiconductor material,which could act as a photocatalyst only under ultraviolet light.Ag had surface plasmon resonance(SPR)characteristics and could strongly absorb the visible and near-infrared regions of radiation.So it had proven to be the best dopant.Zinc oxide(Zn O),silver nanoparticles(Ag)and amphiphilic additive F127 were blended in a graphene oxide / N,N-dimethylformamide(DMF)dispersion.Functional Zn O: Ag-GO successfully introduced by in-situ reduction.Zn O: Ag-GO/F127/PVDF modified membranes with regular sponge-like pores and slender finger-like alternating phases were prepared by immersion phase inversion and deionized water as a coagulation bath(DI).Through FTIR,XRD,XPS diffraction,EDX,TG,AFM and other characterization tests,the permeability,composition,heat resistance and antibacterial properties,tensile effect,surface moisturization of the new graphene oxide-based bimetal material modified PVDF membrane is evaluated.The common organic dye methylene blue(MB)and p-nitrophenol(4-NP)were typical pollutants in wastewater.Its reduced product,4-aminophenol(4-AP),played a vital role in the preparation of certain antipyretics and analgesics in the pharmaceutical industry.Therefore,the performance of modified membranes controlled by coagulation baths was studied by filtering to reduce the main components of these organic dyes.The calculated reaction rate constant was higher than that reported under the same conditions.The reduction efficiency of GO-Ag / PVDF / F127 modified membrane controlled by IPA coagulation bath was 85% and remained stable for at least 1 hour.The photocatalytic reduction efficiency of Zn O: Ag-GO / F127 / PVDF modified membrane for methylene blue(MB)can reach 96.7%within 100 min.Excellent functionality was demonstrated in graphene oxide-based single or multiple metals in polyvinylidene fluoride modified membranes.The immeasurable potential value was shown especially in the field of catalytic reduction wastewater. |
