The study of silicone rubber membrane for pervaporation of acetic acid over water

PDMS membrane,PDMS/PTFE membrane and PP/PDMS membrane were prepared.The membranes were characterized by scanning electron microscopy(SEM),contact angle meter,thermo-gravimetric analysis (TGA)and swelling test.Pervaporation experiments were carried out using these membranes to separate the mixtures of acetic acid/water.The results show that the selectivity and fluxes of membranes increase with increasing of feed concentration.With increasing temperature,fluxes increase and separation factors decrease. The separation factors change to some extent with increasing flow velocity of 14-38L/h while fluxes change little.Support layer has significant influence to the pervaporation performance of membrane,the separation factors of 10wt%feed acetic acid concentration using PDMS,PDMS/PTFE and PDMS/PP membranes at 30℃and 26L/h are separately 2.51,2.74and 2.15,and permeation fluxes are 35.29,42.09and 40.84g/(m2·h).All these observation would be helpful to provide a guideline for the selection of an optimum support layer and an optimum operating condition.