Preparation Of Polysulfone Membrane And Its Application In Industrial Wastewater Containing PVP

Membrane separation technology is a new and efficient fluid separation technology,which has the advantages of high separation purity,simple process conditions,low process cost and less pollution discharge.It is widely used in energy and power,non-ferrous metallurgy,seawater desalination,water supply treatment,sewage reuse,medicine and food and other engineering fields,and is most widely used in ultrafiltration.At present,polysulfone,polyvinylidene fluoride and polyene are the mainstream in ultrafiltration.As a member of many raw material families,polysulfone(PSF)is widely used in membrane separation industry due to its excellent chemical stability and mechanical strength.Especially in microfiltration,ultrafiltration,nanofiltration,reverse osmosis,gas separation,etc.In this paper,the preparation of polysulfone ultrafiltration hollow fiber membrane by solution phase transformation method is studied,and the slurry ratio and spinning process are also discussed.The influences of polysulfone polymer content concentration,additive and its content,dissolving temperature and time,coagulation bath ratio and temperature,core liquid ratio and temperature,air gap on membrane structure and performance are discussed.Based on the test of membrane properties and the observation of microstructure,the recommended recipe ratio is:PS content:18-20%,PVP-30 content:8-10%;PEG600 content:4-8%;DMAc content in core solution:50%-65%;DMAc concentration in coagulation bath:10%-20%.With the rapid development of China’s economy and the rapid development of industrial manufacturing,environmental problems have become increasingly prominent.Wastewater treatment,as an important part of environmental treatment,is particularly important.Membrane separation technology has gradually replaced the traditional methods in various sewage treatment and become the main role,which is inseparable from the technological innovation of membrane manufacturing industry in recent years.Of course,the rapid development of membrane manufacturing industry will also bring about wastewater problems.By analyzing the properties of PVP wastewater from a membrane plant,it is found that there seems to be a large amount of PVP(polyvinylpyrrolidone)in the wastewater.PVP is the most common additive in membrane industry,but it is difficult to degrade.Even MBR(membrane bioreactor)has a low degree of degradation of PVP.Based on the analysis of the properties of PVP,we used the polysulfone membrane hollow fiber module to intercept the PVP in the wastewater,and found that the PVP content in the wastewater can be reduced by membrane separation.The results show that polysulfone hollow fiber membrane has a new application direction.Therefore,on the basis of the study of membrane preparation,polysulfone hollow fiber membranes with different molecular weight were prepared,and they were made into small modules for the filtration test of industrial wastewater containing PVP.Through the ultrafiltration membrane rejection experiment,the suitable polysulfone ultrafiltration membrane was found for PVP wastewater separation experiment.The module cleaning and flux recovery are discussed,and the appropriate operation conditions are selected.According to the experiment,using the polysulfone membrane module with the molecular weight of 6000,the operating pressure is set between 0.05Mpa and 0.06mpa,and the PVP retention rate is more than 98%and can be concentrated to 40 times when the concentration yield ratio is 5:1.Through raw water control,operation cycle control,on-line backwashing and alternative cleaning with 40℃ RO water and low concentration sodium hypochlorite,the flux recovery rate can be maintained at about 85%of the initial flux.