Adsorptive dynamic membrane for water purification: Model and optimization

Abstract

Adsorptive dynamic membrane, consisting of adsorption and filtration, exhibits a desirable efficiency for water purification. However, the entire adsorption-filtration process is affected by many influencing factors, and the operating regulation and process optimization remain still uncertain. The present work deals with the process optimization for adsorptive dynamic membrane treating micro-polluted water. A Box-Behnken response surface methodology was utilized to investigate the effect of operating conditions (dye concentration, agitation speed, carbon nanotubes dosage, Transmembrane Pressure and pH) on the dye removal and flux. The response surface methodology with high coefficients of determination values were fitted to the experimental data, which demonstrated that the polynomial response models fitted well for describing dye removal and adsorptive dynamic membrane filtration efficiency. Based on the design, the optimized conditions for obtaining highest dye removal rate (100%) were dye concentration = 5 mg/L, agitation speed = 210 rpm, carbon nanotubes dosage = 13 g/m2, Transmembrane Pressure = 0.2 mPa and pH = 5.8. The graphical optimization of superimposed contour plots fulfilled the conditions to obtain dye removal >95% and flux >100 L m−2 h−1, as well the interactions among various operating conditions. The work indicated that response surface methodology can be applied for analyzing the effect of operating conditions and acquiring the optimized conditions for adsorptive dynamic membrane treating water/wastewater.