Studies On Surface Modification Of Ceramic Membrane Based On TiO₂Nano-Clay Composite For Membrane Fouling Controlling

As an emerging technique of those which have garnered particularattention in water treatment,inorganic membrane technology has been morewidely available in food industry,chemical industry and biologicalchemistry,energy and environment in recent years.The advantages of excellentchemical stability,thermal stability,selective separation performance andsupport strength give it an enormous commercial value in productionpractice.But because of the high cost of production and operationalmaintenance and membrane fouling problem,the further development ofinorganic membrane has been seriously restricted.With the improvement ofprocess and innovations of technology,those costs have graduallydecreased,while there is still no effective and thorough solution to themembrane fouling problem.Titanium dioxide is a kind of semiconductor material with strong photocatalytic activity.And montmorillonite is kind of clay mineral with strongadsorption capacity to organics in water.Aiming at the problem of membranefouling in application of inorganic membrane,a method was proposed in thispaper using TiO2loaded montmorillonite(TCM) as a modifier to improve thecontamination resistance of ceramic membrane surface in filteration by takingfull advantage of the capacity of adsorption and photocatalytic degradation. Asystem with TCM as raw material, and polyvinyl alcohol(PVA) as dispersionphase is used to make comparative analysis of influencing factors byexperiments to obtain a set of optimal process parameters, which can mix acoating solution where TCM get the best dispersed status.Then effects ofdifferent coating methods such as dip coating directly,coating combined withultrasound and microwave were investigated.After that,a experimental set-upof membrane module was constructed to test the filtration performance ofmodified ceramic membrane.The status of membrane fluxdepression,penetrating fluid quality,the structure and morphology of pores were in observation and monitoring during the filteration process.Andthen,comparative analysis was made to judge the improvement ofcontamination resistance after modification.The results shows that in the filteration the flux depression of modifiedceramic membrane with TCM coated on the surface enjoys a flat fading andthere is also a enhancement in the removal rate of organic contaminant relativeto penetrating fluid quality.The removal rate of8mg/L methyl orange was14.9%by modified ceramic membrane while the unmodified one was just4.7%.Meanwhile,the flux depression ratio of modified membrane was42.8%which was also a little better than40.5%of unmodified one.Combined withstructure characterization of membrane surface and crosssection,contamination resistance of membrane was considered to beenhanced.And it was a active attempt and exploration for the improvement offiltering efficiency and effect,the maintenance of stable flux and therealization of continuous operation in filteration by inorganic ceramicmembrane module.