Studies on Concentration of Simulated Ammonium-diuranate Filtered Effluent Solution by Forward Osmosis Using Indigenously Developed Cellulosic Osmosis Membranes

Abstract

In this study, we discuss the preparations of cellulosic membranes from cellulose acetate (CA), cellulose triacetate (CTA) and cellulose acetate blend (CAB) [blending of CA and CTA] systems and their potential for concentration of simulated ammonium-diuranate (ADU) effluent solution (only uranium and ammonium nitrate) by FO. The membranes are prepared using casting solution of polymers in mixed solvent systems with gelling in ice-cold water followed by annealing in 80°C hot water. Prepared membranes are characterized in terms of separation performance (tested under brackish water reverse osmosis test condition), water contact angle and surface average roughness. The performance of the membranes are evaluated in terms of volume reduction factor using solution of 40,000 ppm of NH4NO3 and 20 ppm uranium as feed and 320000ppm of NH4NO3 as draw solution. It is found that the volume reduction factor increases in the order of CTA<CAB<CA membranes. The effect of different draw solutions on volume reduction for the same system using CA membrane is also evaluated. Almost no leaching of uranium is found to the draw solution side for all the membranes. Possibility of using the FO process in a simpler way (as membrane pouch) to concentrate this simulated ADU filtered solution has been ascertained.