Preparation Of Microporous Polymer Electrospun Membrane And Its Adsorption Properties

In recent years,the world has suffered from serious water scarcity and contamination,which is mainly caused by industrial,agricultural and domestic wastewater discharge.Membrane separation technology has been widely used in water treatment owing to its low energy consumption,environment friendly and easy to operate.Traditional polymer membrane with good mass transfer efficiency but failed to meet the needs of adsorption performance due to its wide pore size distribution and small surface area.Microporous organic polymer has superiorities such as small pore size and high surface area but the mass transfer resistance is relatively high.In this paper,the advantages and disadvantages of both materials are well considered by preparing a membrane with polymeric intrinsic microporosity PIM-1 and the adsorption performance was systematically studied.Firstly,the soluble polymers of intrinsic microporosity PIM-1 was synthesized by polycondensation.The gel permeation chromatography(GPC),nuclear magnetic resonance(1H NMR),fourier transform infrared spectroscopy(ATR-FTIR)and thermogravimetry(TG)measurements were used to characterize the molecular weight,surface chemical composition,and thermal stability of the polymer.The results show that PIM-1 was successfully synthesized and its average molecular weight was 52,7000 g/mol.Afterwards,PIM-1 membrane was prepared by electrospinning technology.The surface morphology and pore size analysis of PIM-1 electrospinning fiber membrane were characterized by field emission scanning electron microscopy(FESEM)and BET measurement.The results show that when the solid content of PIM-1 is 15 wt%,the morphology of PIM-1 membrane is the best,micropores,mesopores and macropores exist after heat treatment,which lays a foundation for the study of adsorption performance of PIM-1 electrospinning membrane.Finally,the PIM-1 membranes with a solid concentration of 15 wt%were used to study the adsorption of carbendazim and phenol.Results show that the equilibrium adsorption capacity for carbendazim and phenol was 0.072 mmol/g and 0.660 mmol/g respectively.Langmuir model was preferable to describe the adsorption isotherm,and the adsorption kinetic was fitted well to the pseudo-second-order rate model.The adsorption capacity for carbendazim and phenol were decreased with the increase of temperature and pH value.For recycling performance,the recovery rate for carbendazim and phenol was both above 95%after recycled 10 times.All above indicate that the prepared PIM-1 electrospinning membrane is an effective adsorbent membrane material.