Preparation Of Glass Hollow Fiber Membrane And Its Surface Modification Properties

The treatment of organic dye wastewater has become one of the urgent problems to be solved in today's society.Membrane separation technology has attracted the attention of environmental protection workers with it's advantages such as high separation efficiency,no additive,simple equipment and operation,easy control of the process and no secondary pollution.It has been studied since last century and the technology has become mature.Inorganic hollow fiber membrane,as a kind of membrane,has been widely used in dye wastewater due to its excellent thermal stability,self-supporting structure and good reproducibility.This study glass powder as raw material,through the dry and wet spinning technology and sol-gel method of dye wastewater(Congo red,methylene blue,carbon black)have good interception effect of surface modification hollow glass fiber composite membrane,after 6 cycles The membrane still retained more than 95%of Congo red.In addition,the modified membrane has the characteristics of simple preparation,low cost of raw materials,good retention effect and so on,and has a good application prospect.The hollow glass fiber membrane with asymmetric pore structure was prepared by the method of immersion precipitation phase conversion and sintering.The thermal stability and resistance to acid and alkali corrosion of hollow glass fiber membrane were discussed.The results show that after calcination at 660?,the quality of the hollow fiber precursor membrane is basically unchanged and the thermal stability is good.The contact Angle proved that the acid-base treatment made the membrane show higher hydrophilicity.Through mutual evidence of XRD,XPS and FTIR,and further analysis,it is confirmed that after calcination at 730°C,the film has phase separation,with Na₂B₄O₇phase and SiO₂phase.SiO₂phase in the system is eluted by strong acid/alkali corrosion,and Na₂B₄O₇phase is also eluted partially.Then,it was found that hollow glass fiber membrane can retain it's structural integrity in the environment of strong alkali,although the structure will be destroyed in strong acid,it can basically retain it's complete structure in weak acid.Therefore,hollow glass fiber membrane has good thermal stability and acid and alkali corrosion resistance.The surface modified composite membranes of hollow glass fiber coated with ZrO₂or ZnO coated were characterized,and it was found that the modified film still retained hydrophilic property.SEM,BET and porosity test jointly indicated that with the increase of coating number,the pore diameter of the film decreased and the porosity decreased.SEM and roughness together indicate that the number of coatings increases,and ultra-thin coatings gradually form on the outer surface of the film.The presence of ZrO₂and ZnO makes the modified membrane show better anti-pollution performance than the based membrane,but the number of times of ZnO coating should not exceed 2.XRD and XPS are used to prove that the coating has been successfully coated on the surface of the membrane.The results of weight loss rate test showed that ZrO₂and ZnO coatings had certain anti-acid and alkali corrosion properties and had certain protective effect on the base film.The modified membrane was used in the experiment of dye wastewater removal.The results of 2h pure water flux and interception showed that the coating was selective for dye solution separation.In addition,after 6 cycles,the interface binding between the coating and the based membrane is still stable,and the modified membrane has shown high efficiency for removing Congo red dyes in long-term stability tests ZrO₂and ZnO modified membranes have a retention rate of over 95%and over 99%respectively)and good durability.