Preparation And Applied Research Of Nanofiber Ultrafiltration Membrane

Electrospinning is a new efficient method for preparing nano fiber, has the advantages such as simple equipment, easy control, low cost etc. The preparation of nano fiber can reach nanometer level, non-woven fabric made from nano fiber has the advantages of high porosity, good uniformity, high specific surface area, thus giving the electrostatic spinning especially widely application prospect.In this paper,combine polyvinyl alcohol which with high water absorbability and high separability with high water permeability of polyether sulfone,preparation of PVA/PES composite ultrafiltration membrane, electrospun PVA nanofibers, and the load of bentonite in the surface, through the analysis of scanning electron microscope and tensile test of different concentration of polyvinyl alcohol, when the concentration of PVA at 16%, the uniform load bentonite fiber distribution, and the tensile properties optimal compared with other concentration,and with optimal tensile properties compared with other concentrations;Electrostatic spinning PES nanofibers, with N-N dimethyl formamide as solvent, polyvinyl pyrrolidone as the pore forming agent, enhance the mechanical properties by bentonite, through orthogonal experiment analysis the best mixing ratio, known that, when the concentration of PES、PVP and bentonite are 22%, 8% and 22% respectively,the spinning effect is best, Remove pore forming agent PVP by soaking process nylon 66 as support layer, In the spinning conditions of 15 Kv and 20 cm experiments were performed in accordance with the above conditions,then the 16% load of bentonite PVA spinning solution spinning to surface of PES.After cross linking, immerse to get rid of the solvent, drying, obtained PVA/PES composite ultra-filtration.Analysis the structure of themembrane surface through the testing such as scanning electron microscope,and the membrane properties after crosslinked composite,it is sure that dense composite membrane can be prepared, and the effect is obvious.It can see from the SEM images,PVA nano fiber ultra-filtration membrane surface has been loaded bentonite successfully,and the concentration in 16% with the most uniform distribution.On the nano fiber ultra filtration membrane, after the recombination after crossing-linking between PVA cortex and PES base forming a composite layer of dense, and a uniform fiber distribution, overlapping into porous structure;Analysing of in spectrum show that in 3300cm-1 appeared ether ketone base peak of stretching vibration, described in the composite process between cortex and grass-roots formed a new connection structure, achieving the composite effect; Thermo gravimetric analysis showed that, the initial decomposition temperature of composite ultra filtration membrane which is before processing is 200 oC, the weight loss rate of 24%, after treatment of initial decomposition temperature reaches 310 oC, the weight loss rate of 27%, enhanced the thermal stability of composite ultra filtration membrane;Tensile test showed that,Breaking load forces tend to increase first and then decrease, fracture length prior to treatment is 40 mm,the elongation at break of 159.23%, after treatment for 52 mm fracture length, fracture elongation is 255.43%, enhance the mechanical properties of composite ultra-filtration membrane, avoids the influence of mechanical factors in the ultra-filtration process.In order to test the performance of ultra-filtration composite membrane, choosing bovine serum albumin(BSA) as the standard substance,before processing the water flux is 20.69, the porosity of 18%, with low filtration efficiency, and the membrane easy to plug the film hole Because the accumulation of small molecular substances,Thus the ultra-filtration membrane fouling,after processing the water flux of composite membrane is 94.67??12?? hmL, the porosity is 43%, the filtration efficiency is higher than that before treatment,and composite ultra-filtration membrane after processing with the formation of the stable connection structure,so the small molecules in the filtration process will remain in the surface of PVA nano fiber ultra-filtration membrane, can not enter into the PES film structure, thereby avoiding the membrane fouling phenomenon caused by the material blocking;When select bovine serum albumin as the standard substance, the interception rate of ultra-filtration membrane must reach more than 90%, through the test obtained that, before processing retention rate of composite ultra-filtration membrane is 85%, the average pore size is 34 nm, did not meet the standard requirements of interception,after processing, interception rate it reached 97%, the average pore size is 55 nm,meet the standard requirements, and meet the experimental requirements standard of composite membrane.