Performance of vacuum poly(propylene) membrane distillation (VMD) for saline water desalination

Abstract

In this study, commercial poly(propylene) (PP) hollow fiber membrane was used for desalination of highly saline water via VMD. The effect of operational conditions, such as feed temperature (i.e., 45–64°C), feed flow rate (i.e., 0.4–0.6L/min), feed concentration (i.e., 35–100g/L), and vacuum pressure (i.e., 12.7–28kPa (abs)), on hollow fiber performance was studied. The hot brine was circulated through the lumen side of the hollow fibers.The results demonstrated that the water permeate flux of about 66 (kg/m2h) was achieved at the operating conditions defined by 35g/L, 65°C, 0.6L/min (pertaining to feed concentration, temperature, and flow rate, respectively) under 12.7kPa (abs) vacuum pressure, whereas salt rejection was 99.99% and the conductivity of the permeate was less than 10 (μS/cm). In order to minimize the number of experiments and optimize the influence of operating conditions on permeate flux, Taguchi method was used and ANOVA was implemented to determine the contribution of each factor to the observed output. The findings revealed that the feed temperature was the most influential factor in determining the permeation flux, followed by vacuum pressure, feed concentration and feed flow rate.