Development of a novel method for sodium azide removal from aqueous solution using amberlite IRA-900: batch and column adsorption studies

In this work, the adsorption characteristics of amberlite IRA-900 chloride resin (amberlite) for azide ions sorption were investigated. The elimination of azide ions from aqueous solution in the batch and continuous (fixed-bed column) was performed. The optimum conditions in the batch system were found, namely a pH of 6, an amberlite dose of 7 g/L, and a reaction time of 50 min. The kinetics of the process was also investigated with four kinetic models including pseudo-first and second-order, Elovich, and Morris–Weber. The pseudo-second-order model showed better fitting with kinetic data. The Temkin, Dubinin–Radushkevich (D–R), Langmuir, and Freundlich were utilized for isotherm study. The Langmuir equation showed a better fitting of the equilibrium data. amberlite indicated a high capacity for azide elimination from aqueous solutions at different concentrations. High desorption efficiency (for amberlite recovery and recycling) was also obtained using 10% (w/w) NaCl. The recovered amberlite also indicated a high ability to remove the azide ions. In the continuous system (fixed-bed column), the effects of key parameters, namely bed heights and flow rates, were comprehensively studied.