Bioregeneration of single use nitrate selective ion-exchange resin enclosed in a membrane: Kinetics of desorption

The increasing use of highly-selective resins for the removal of anions from contaminated drinking water has increased the demand for these resins and increased the waste generated during the treatment process. The proof of concept for the extension of the use of these resins by use of multi-cycle exhaustion/bioregeneration has been demonstrated previously. To fully develop a process for the commercialization of this technology it is important to determine the effect of the temperature and salt concentration on the nitrate desorption rates to model chemical and biological processes. Results show pseudo-second order kinetic analysis explains the experimental data very well. The initial desorption rates were significantly different in different salt concentrations and temperature; higher and lower value for 6% and 2% salt, higher and lower value at 35°C and 12°C. The mean value of the equilibrium concentration at 12°C was significantly lower than 23°C and 35°C with no effect of salt concentration on the temperature means.The results of this research provide much needed data of the kinetics as well as the typical equilibrium as such is a significant contribution to the overall design of systems for the reuse of highly selective resin in multi-cycle ion exchange processes without any further disinfection or cleaning procedures.