Effects Of Solvent On The Properties And Morphology Of Filtration Membrane

Water shortages,water pollution is seriously exacerbating the water shortage,so the availability of water is less,creating challenges for the development of industry and agriculture and the people's livelihood.Agriculture as water conservation,make good use of recycled water is one of the important measures to solve agricultural water tension,at the same time,high efficiency water saving irrigation technology is also beneficial to ease the tight agricultural water.Water quality is a key part of the implementation of the above technologies,and membrane technology as one of the main water treatment technologies is becoming more and more important.In this experiment,polyether sulfone was selected as the film-forming material,and the ultrafiltration membrane was prepared under four kinds of solvents to study effects of solvent sort on the properties and morphology of PES and PES-g-PVP filtration membrane and application of ultrafiltration membrane in irrigation water filtration of farmland.This research systematically state the effect of solvent sort and polymer concentration on the performance and morphology of PES membrane,with and without PVP additive in the cast solutions of membranes.Besides,the similar studies on graft copolymer PES-g-PVP have also been carried out.According to the experimental results,18 % is the best polymer concentration for membrane casting due to the appropriate viscosity of cast solution.Moreover,the most suitable conditions for membrane casting by Nonsolvent-Induced Phase Separation(NIPS)method are the humidity of 40%,the environmental temperature of 24 oC,the thickness of the cast blade of 150 ?m or 200 ?m exposure time of 5s and coagulation bath temperature of 19 oC.In our experiment,PES is modified through grafting reaction induced by gamma irradiation with hydrophilic N-vinyl-pyrrolidinone(NVP).With the existence of NVP,PES-g-PVP was synthesized after 6 h and 6 kGy gamma irradiation.Pure water flux,BSA solution flux,contact angle,the viscosity of cast solution,scanning electron microscope(SEM)and thermodynamic phase diagram were used to characterize the morphology and performance of formed ultrafiltration membranes.It is illustrated that,with the addition of PVP,the contribution degree of 4 solvents on PES membrane flux is DMF>DMAc>NMP>DMSO,on the premise that rejections of BSA are above 90%.When it comes to the membranes without addition of PVP,the membranes cast with DMSO solution demonstrate the largest flux volume.After all,the influence of solvent on membrane formation depends on whether the additive is added or not.With regard to modified PES-g-PVP,the material with higher graft rate results in larger flux volume.While NMP and DMSO are used as solvents,the flux volume of the PES-g-PVP membrane will surprisingly increase.But the addition of PVP will in large scale increase the flux volume of the membranes using DMAc as solvent.