Development of a novel moving bed with liquid-pulse and experimental analysis of nickel removal from acidic solution

Abstract

A prototype of moving bed has been developed and applied to remove Ni from model solutions of industrial wastewater for the recycling of the solution and the metal. The apparatus has been simply designed by installing a plate with a hole to the bottom of resin bed and by giving a pulse to liquid. This apparatus allows us to control the resin flow rate by changing the liquid flow rate and the cross-sectional area of the hole. The liquid-pulse gives dual advantages; the prevention of clogging of resins and stabilization of the resin flow rate. Removal of Ni from the acidic solution has been carried out by using a strong cation resin, DIAION SK1B and the column performance has been evaluated in terms of removal fraction of Ni and ion-loading fraction of the resin under the various conditions. The column showed the high performance; the removal fraction was more than 0.9 in every system investigated and the ion-loading fraction was over 0.8 in some cases. Good separation of high removal and ion-loading fractions is achieved by the operation with the large bed height and with the large hole diameter. The continuous removal of Ni in the various concentrations of HCl has been discussed with the ion exchange equilibrium and kinetics. The values of equilibrium coefficient and ion exchange capacity have been determined in relation to the concentration of hydrogen ion. The effective diffusivity of Ni within the resin particle increases with the increase in the concentration of hydrogen ion.