Sweeping gas membrane distillation of sucrose aqueous solutions: response surface modeling and optimization

Abstract

Response surface methodology and desirability function approach have been applied for modeling and multi-response optimization of sweeping gas membrane distillation process used for concentration of sucrose aqueous solutions. Response surface models have been developed to predict the permeate flux and the sucrose concentration rate. The models have been statistically validated by ANOVA. The sucrose rejection factor was found to be greater than 98.9% and therefore the response surface model can not be developed for this response. The models have been used to perform the overall desirability function. In addition, the overlap contour plots have been drawn to study the interaction effects between operating parameters on both the permeate flux and the sucrose concentration rate, to identify the desirability zone and to determine the optimal point. The optimal operating conditions were found to be 70.9 degrees C feed temperature, 2.09 m/s air circulation velocity and an initial sucrose concentration of 223 g/L. Under these conditions the measured permeate flux 1.077 x 10(-3) kg/m(2) s and the sucrose concentration rate 4.686 g/L h were found to be the highest values in this study confirming the validity of the applied sweeping gas membrane distillation optimization procedure.