Evaluation of Nickel Sulphide Prepared by Different Routes for Removal of¹⁰⁶Ru from Alkaline Radioactive Liquid Waste

Abstract

An attempt has been made to synthesize nickel sulphide (NiS) compound by different routes. The NiS material thus obtained was coated on polymethyl metha acrylate (PMMA) beads to form a composite material, which was subjected to its performance evaluation for uptake of 106 Ru from low level radioactive liquid waste (LLW) stream. Distribution Coefficient (K d ) of 106 Ru from LLW using NiS-PMMA composite beads was found to be in the range of 9000-12000 (ml/g). The effect of various parameters viz. pH, ionic strength, temperature, time equilibration, etc. towards the uptake of 106 Ru was investigated. The sorption mechanism was also studied. The DG, DH, and DS value for sorption were evaluated. The sorption was observed to be spontaneous and endothermic in nature. From the practical utilization point of view, the rate of uptake of 106 Ru by the composite material was studied. The data of sorption was investigated with Lagergren first-order, pseudo-firstorder, and second-order plots. Its intraparticle diffusion mechanism was studied with the Weber Morris model. The kinetics was found to follow a pseudo-first-order pattern with intraparticle diffusion. However, intraparticle diffusion is not the rate controlling step.