Fabrication of asymmetric ultrafiltration membranes from natural zeolite and their application in industrial wastewater treatment

In this study, a performance evaluation of tubular ultrafiltration (UF) zeolite membranes developed from natural zeolite materials during the treatment of two industrial effluents is reported. These membranes were prepared via the slip casting process on low-cost natural zeolite supports of average pore size 0.55 mu m. After sintering at 880 degrees C for 3 h, the average pore size of the membranes reduced to 8-11 nm. The membrane morphology was checked using scanning electron microscopy, after which the membranes were tested by applying them to treat wastewaters from the cuttlefish processing industry and the electroplating industry. This performance evaluation revealed that the pure water permeability of the membranes ranged from 118 to 176 L/h m(2)bar, and the membrane flux during wastewater treatment was consistently higher than 74/L h m(2)at 3 bar. All the prepared membranes displayed good chemical oxygen demand (COD) removal potential (> 85%), and the membrane prepared using the modified zeolite MZ/Z (which was characterized by a positively charged surface) displayed a maximum Fe(3+)rejection rate of 90%. These results will be utilized to evaluate optimized and upscaled membranes for the treatment of dye industry wastewaters in Mediterranean countries.