Preparation Of Ultrafiltration-adsorption Dual Functional Membrane And Its Performance For Simultaneous Removal Of Multiple Pollutants

In order to cope with the technical challenges of simultaneous removal of multi-component pollutants by membrane-based water treatment technology under low pressure,this paper proposes to combine nanoadsorbents and ultrafiltration membranes to build a dual-function membrane(DFUF)with both ultrafiltration and adsorption functions.And study its simultaneous removal of multi-component pollutants in water.The hollow mesoporous carbon nanospheres(HMCNs)were prepared and filled into the finger pore structure of polyethersulfone ultrafiltration membrane by cross-flow method to obtain the DFUF membrane.The removal of pollutants by DFUF membrane was carried out by using trace amounts of tetracycline and bovine serum albumin as small-scale organic pollutants and macromolecules,respectively.The main contents are as follows:The mesoporous carbon nanospheres(MCNs)and hollow mesoporous carbon nanospheres(HMCNs)were synthesized via a "silica-assisted" method.The synthesized HMCNs and MCNs nanospheres were characterized by thermal gravimetric analyzer(TGA),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and N2 adsorption/desorption.The influences of solution pH,adsorption temperature,initial concentration,competitive anions,and humic acid were also examined.The results indicated that HMCNs possess distinctive structures,including porous shells and hollow cavity.The BET surface area of HMCNs and MCNs nanospheres were 1913 m2 g-1 and 1171 m2 g-1,respectively.And the MCNs and HMCNs nanospheres were characterized with high specific surface area and adsorption active sites,which greatly enhances the adsorption performance for the removal of organic pollutants.The maximum adsorption capacity of HMCNs and MCNs nanospheres were 701.4 mg g-1 and 564.8 mg g-1,respectively.Adsorption capacity of tetracycline was seriously affected by solution pH,adsorption temperature,humic acid,and initial concentration.However,competitive anions can hardly affect the adsorption capacity of tetracycline.After five cycles,the regeneration efficiency of HMCNs was 91.74%.PES flat membranes were prepared via the nonsolvent induced phase separation(NIPS)process.Then,the MCNs and HMCNs were immobilized in the finger-like pores of PES membrane by cross-flow method.The DFUF membrane was characterized by thermal gravimetric analyzer(TGA),scanning electron microscopy(SEM),and N2 adsorption/desorption.The HMCNs wt%value and MCNs wt%value in DFUF membrane were 37.79 wt%and 37.82%,respectively.Meanwhile,the pure water flux and BSA rejection of DFUF membrane were also examined.The pure water flux of PES membrane and HMCNs-loaded membrane were 432.3 L m-2 h-1 and 270.0 L m-2 h-1,respectively.And the BSA rejection of PES membrane and HMCNs-loaded membrane were 72.31%and 71.05%,respectively.Moreover,DFUF membranes possessed excellent simultaneous removal of complex contaminants,which were able to remove tetracycline and PEG(Mw = 600 kDa)simultaneously.In one cycle,the adsorption of tetracycline by DFUF membrane was over 90%,while the retention of PEG was more than 99.5%.In addition,the.regeneration efficiency of DFUF membrane was also above 90%.In summary,DFUF membrane will play an important role in the process of water treatment in the future.