Effect of unmodified and modified montmorillonite on the properties of PCL based ultrafiltration membrane for water treatment applications

This work presents the preparation of membranes using polycaprolactone (PCL), a biodegradable polymer incorporating unmodified and modified nanoclay using phase inversion technique. The membranes prepared with the incorporation of 0.1 g to 0.4 g of unmodified nanoclay and 0.05 g to 0.15 g of modified nanoclay were studied with respect to porosity, hydrophilicity, chemistry, mechanical and thermal properties and morphological characteristics. The results showed that the membrane incorporated with unmodified nanoclay has enhanced strength and porosity compared to the membrane with modified nanoclay and neat PCL. An increase in water permeability is shown by the incorporation of unmodified nanoclay and contact angle measurement results revealed an increased hydrophilicity with a decrease in membrane roughness which was confirmed using AFM analysis. The surface morphology was examined using SEM analysis and the results revealed that on adding unmodified nanoclay, the average pore size decreased from 6.2 μm to 4.5 μm and for membranes with modified nanoclay, the average pore size was found to be 1 μm. The prepared membranes were tested for the rejection of Congo Red and the performance were analysed.