Fabrication of ZSM-5 Zeolite Dispersed Polyethylene Membranes via Thermally Induced Phase Separation Method

Abstract

Simultaneous increase in the permeance coefficient and mechanical strength and decrease in membrane fouling pose a challenge to polymeric membrane researchers. In this work, polyethylene (PE) polymer membranes, to which ZSM-5 zeolite particles have been added, were fabricated via thermally induced phase separation (TIPS) method. The fabrication of membranes is done in two steps; in the first step, in a constant coagulating bath temperature, the ratio of zeolite to polymer varies within 0-30% range and the changes in the pure water permeance and mechanical strength were assessed. The results are indicative of 60% increase in pure water permeancy, 300% increase in the mechanical strength and 400% increase in the ultimate tensile strength in pure water permeancy test in the membrane containing 30 wt% of zeolite. In the second step of optimization of the membrane’s structure and performance, the experimental design and response surface methodology (RSM) is applied to measure the individual and mutual effects of zeolite concentration, membrane’s thickness and bath temperature parameters on the water permeancy and mechanical strength. The results indicated that the water permeancy improved with any increase in the zeolite concentration and coagulation bath temperature while the membrane’s thickness scarcely affected the water permeancy. The interesting point was that any increase in the membrane thickness improved mechanical strength. Finally, the performance of membranes was evaluated using the collagen solution. The results showed that the membranes containing zeolites were more fouling resistant and the degree of resistance increased by increasing the zeolite content.

Keywords

• polyethylene membrane
• zsm-5 zeolite
• thermally induced phase separation
• mechanical strength
• water permeancy