Regeneration of a perchlorate-exhausted highly selective ion exchange resin: Kinetics study of adsorption and desorption processes

Perchlorate is a stable and soluble ion that can last for decades in the environment and can cause a number of environmental and health issues. Perchlorate is commonly removed using highly-selective ion-exchange resins that are replaced after exhaustion and incinerated or disposed in a landfill since there is no viable regeneration method. The major limitations in regeneration of single use resins is achieving complete desorption of perchlorate. The sustainability of treatment processes for perchlorate contaminated water can be achieved by regenerating the exhausted resin. As the first step of resin bioregeneration study, research on the adsorption and desorption kinetics of the perchlorate ion from a strong base anion exchange resin was conducted. Different chemical reaction and diffusion models were analyzed using experimental data. Both adsorption and desorption experimental data were best described by the Pseudo-second order model with adsorption rate constants of 2×10−3±0.001 (g/mg/min) and desorption rate constants of 5×10−2±0.01 (g/mg/min). These results suggest that the rate limiting stage for adsorption and desorption of perchlorate ion into the resin can be chemisorption.