Study On The Preparation And Performance Of MOF/PVDF Composite Membrane

Polyvinylidene fluoride(PVDF)has good mechanical properties,thermal stability,chemical stability,oxidation resistance and hydrophobicity,and has very good film forming properties.Therefore,PVDF is a widely used membrane material.MOF are interconnected by inorganic metal centers(metal ions or metal clusters)and bridged organic ligands by self-assembly,forming a kind of crystalline porous material with periodic network structure,showing great development potential and attractive prospects.1.The PVDF membrane is hydrophobic,but the prepared membrane surface has a contact angle of between 90 and 105°and generally does not meet the requirements for hydrophobic membranes in industries such as distillation,desalination and gas adsorption.Based on the hydrophobicity of ZIF-7 nanomaterials,the PVDF membranes were hydrophobically modified to investigate the effects of different ZIF-7 nanomaterials on the structure and anti-wetting properties of PVDF membranes.The results show that the ZIF-7 nanomaterials are successfully blended with PVDF polymers.Compared with the pure PVDF membranes,the surface and section mor:phology of the M(2)composite membranes are significantly improved,and the roughness is significantly increased.The M(2)contact angle increased to 134.5°,and the hydrophobicity increased.The permeability of M(2)to O2,N2,and CO2 increased by 54.01%,39.68%,and 41.28%,respectively.In addition,M(2)still showed the highest recovery and good anti-wetting performance after immersion in water for 10 hours.2.The problem of membrane fouling is an inevitable problem in all membrane technologies,which limits the commercial application of membrane technology.Therefore,the preparation of antifouling or low-pollution membranes has become the key in the field of membrane modification.The results show that the Cu-BTC nanosheets are successfully blended with PVDF polymer.Compared with the pure PVDF membrane,the surface and cross-section of the M(5)composite membrane are obviously improved,and the water flux is increased to 84.73kg m-2·h-1.M(5)also has the highest recovery water flux,and also exhibits excellent retention of BSA and the least amount of adsorption to BSA.The 3‰sodium hypochlorite solution has a good cleaning effect on the membrane.