Elution of ion exchange resins by use of ultrasonication

The feasibility of using ultrasound to enhance the elution of three ion exchange resins was investigated. A laboratory-scale elution column immersed in an ultrasonic bath was used to investigate three elution systems. XAD7-Au (eluted with NaOH, at a pH of 10), IR120H-Cd (eluted with HCl) and A375-SO42- (eluted with saturated lime solutions). The physico-chemical stability of the resins was not affected adversely by sonication, with the exception of the XAD7 resin, which showed very slight degradation after prolonged exposure. Ultrasonic radiation improved the elution recoveries and kinetics considerably. This could possibly be attributed to an increase in counter-ion diffusive transport caused by acoustic vortex microstreaming, as well as the prevention of precipitation that can lead to the blockage of ion exchange sites. (C) 2000 Elsevier Science B.V. All rights reserved.