The Preparation Of Crosslinked Chitosan Quaternary Ammonium Salt/Polyethersulfone Ultrafiltration Membrane And Its Adsorption To Cr(?)

At present,environmental pollution,resources wasting and energy shortages have become increasingly prominent,which restricting the sustainable development of society.Ultrafiltration is an advanced membrane separation technology,which plays an important role in the rational utilization of water resources,and has been widely used in the treatment of drinking water.However,in the process of drinking water treatment,ultrafiltration membrane will be polluted,and it can not remove the harmful molecules(such as bromate,chromate,etc.),which greatly limits the application of ultrafiltration membrane in water treatment.Therefore,in order to solve this problem,a new type of adsorption ultrafiltration membrane was prepared,and we study its pure water flux,anti fouling performance and the adsorption to Cr(?).The casting solution consists of polyethersulfone,N,N-dimethylacetamide,poly(vinylpyrrolidone),and cross-linked quaternary chitosan salt.CQS/PES ultrafiltration membranes were prepared by phase inversion method.The effect of the addition of cross-linked quaternary chitosan salt on the structure and properties of polyethersulfone ultrafiltration membranes were studied.The characterization of polyethersulfone ultrafiltration membranes were measured by scanning electron microscopy(SEM),atomic force microscopy(AFM),Fourier transform infrared spectroscopy(FTIR),contact angle measurement,pure water flux and bovine serum albumin(BSA)rejection methods.The results show that with the content of cross-linked quaternary chitosan salt increased from 0wt% to 10wt%,the structure and the pure water fluxes of the membranes had no obvious change;membrane contact angle increased from 67 degrees to 83 degrees,the hydrophilicity of the membrane is reduced;at the same time,the initial film of bovine serum protein retention rate decreased from 90% to 61%;membrane fouling and flux recovery rate decreased.CQS/PES ultrafiltration membranes were used to adsorb Cr(?)solution and we studied its adsorption to Cr(?).The results show that the rejection to Cr(?)increased from 20% to 87%,when the content of cross-linked quaternary chitosan salt changed from 0wt% to 10wt% in the membranes.And Cr(?)ions could be eluted by treatment with 1mol·L-1 NaCl solution.When the content of cross-linked chitosan quaternary ammonium salt was more than 7.5 wt%,the recovery rate of membranes was more than 95%.Adsorption data were fitted with the use of a pseudo-second-order kinetic model and the Langmuir isotherm models.