Optimization of Process Parameters using Response Surface Methodology for PCL based Biodegradable Composite Membrane for Water Purification

The biodegradability of polycaprolactone (PCL) and the anti-fouling property of TiO2 are utilized for the preparation of membranes for water treatment. Polyethylene glycol (PEG) is added to the polymeric solution to increase the pore formation in the membranes. The composition of PEG and TiO2 nanoparticles was optimized using the central composite design and response surface methodology. Quadratic models were developed for the responses porosity and contact angle, and the optimum compositions obtained for PEG and TiO2 were 6.24 and 1 wt%, respectively. The competency of the membrane for water treatment is studied using different characterization techniques such as TG analysis, FTIR to determine the chemical interactions, UTM to examine the mechanical strength, AFM for membrane roughness determination and morphological analysis using FESEM. A twofold increase in the overall porosity and a twentyfold reduction (approx.) in pore size were observed for the composite membrane from FESEM images. The anti-fouling ability of TiO2 resulted in a flux recovery of about 90% for the composite membrane compared to the PCL–PEG membrane after bovine serum albumin filtration. Also, the presence of TiO2 increased the reversible fouling component, which can be easily removed by cleaning/backwashing. Thus, the PCL–TiO2 combination would be a better alternative for the membranes used in water treatment applications.