In order to investigate the effects of the variables on the pervaporation (PV) performance of the hydrophilic PAA-Al2O3composite membrane for the ethanol-water mixture,the central composite rotatable design (CCRD) was used,and the permeate flux and selectivity were chosen as the experimental responses.Regression models were developed as the functions of the graft concentration of acrylic acid,the operating temperature,and the inlet ethanol concentration.From the regression analysis of the pervaporation of ethanol-water mixture,the permeate flux was found to be significantly influenced by operating temperature and then ethanol concentration.Meanwhile,the selectivity was significantly influenced by the interaction of temperature and ethanol concentration,followed by the graft concentration of acrylic acid.In order to optimize the flux and selectivity of ethanol-water azeotropic mixtures,the desirability function approach was applied to analyze the regression model equations.For the 95%(wt) ethanol-water azeotropic mixture,the optimum graft concentration of acrylic acid and temperature were found to be 8%(wt)and 55.9 ℃,respectively;and the value of overall desirability was 0.50,which indicated that the results of optimization for the separation of ethanol-water azeotropic mixture are acceptable.
