Separation of terbium from aqueous phase employing hollow fibre supported liquid membrane with EHEHPA as carrier

Hollow fibre membrane (HFM) operation in supported liquid membrane mode has been successfully employed for the separation of terbium from lean aqueous media by using EHEHPA (PC88A) as an extractant. The effects of different process parameters such as aqueous-phase acidity, extractant concentration, phase ratio and flow rate were evaluated to optimize the condition for effective transport of terbium from a lean nitrate aqueous medium. Diffusional parameters were evaluated to establish the rate-determining step in Tb(III) transport from the feed side to the strip phase. Under optimized conditions of 1 M PC88A, 0.1 M HNO3 as aqueous feed phase, 100 mL/min flow rate and phase ratio of 62:1, recovery of terbium was >95% from lean source. The process was successfully demonstrated in continuous mode of operation for concentrating the Tb(III) value from ppm to g/L under circulation mode while processing 30 L of aqueous phase. Considering the fast transport of terbium, three cycles HFM-SLM approach was proposed to concentrate Tb from 30% to 95%.