The Preparation Of Inorganic Microporous Membrane And Application In Lignin Separation

Global energy problems are currently and urgently need to be solved.Lignin is useful and versatile as the second-largest biomass,compared with the cellulose.In this study,AL₂O₃HDTMS-ZrO₂ and GOPTS-Zr O₂ membranes were successfully synthesized for separation of lignin from black liquor.Firstly,Al₂O₃ and ZrO₂ membranes were successful synthesized via rubbing method.The SEM analysis depicted that Al₂O₃ membrane without big pore structure and any defects on the surface.The antifouling performance of the membrane was assessed via the filtration of black liquor simulation.The membrane showed higher flux which was 20 kg/?m²·h?.The results showed that:weight average molecular weight of lignin were 1000 Da.Moreover,the continuous operation still maintained good separation performance after 24 h,indicating that the Al₂O₃ membrane had good stability.Furthermore,this study synthesized two graft modification membranes through a simple,economic way.The SEM analysis results depicted that membrane without big pore structure and any defects on the surface.And these two films did not loss after used.And these membranes through deionized water flushing,flux can be resumed more than 90%.Through the separation,ligin with narrow molecular weight distribution was obtained about 900 Da.The first kind of ZrO₂ modified membrane was applied to isolate lignin from pulping black liquor.But as temperatures rise flux can reach 110 kg/?m²·h?.And this HDTMS-ZrO₂membrane cleaning has been performed was easy.The second GOPTS-Zr O₂ membrane through ATR-FTIR and SEM analysed the memebrane.Silane coupling was chemically-grafted on the surface of GOPTS-Zr O₂ membrane.The effect of each factor on film performance was also discussed.It is shown that when the temperature increased,the flux increased sharply.And with the increasing of the reaction time in the process,the flux was 25 kg/?m²·h?.The results showed that the optimal cleaning at room temperature could restore the membrane's standard permeability to higher than 90%of the original permeability.