Evaluation of Weak and Strong Basic Anion Exchange Resins for NOM Removal

Abstract

The feasibility of using ion exchange resins in stirred (suspended) mode operation for the removal of natural organic matter (NOM) from surface water was investigated. Resins were compared in terms of their NOM removal capacity, kinetics, and regeneration efficiency under batch and consecutive batch loading conditions. The dominant mechanism for NOM removal with the strong basic A860 resin was ion exchange whereas a combination of ion exchange and surface adsorption governed the removal with the weak basic A847. The estimated limiting capacity (qm) and the equilibrium constant (α) for A860 were higher than the ones for A847, showing greater affinity of A860 for natural organic matter. Also, under consecutive batch loadings, the strong basic resin showed greater removal (∼10% higher) compared to A847. Different regeneration scenarios were also examined and A860 resin showed a superior regeneration efficiency (∼20%) compared to A847. Overall, findings indicated the strong basic resin as a better candidate for the removal of NOM from surface water. This paper proposes an evaluation scheme for the selection of appropriate ion exchange resins aiming to reduce NOM in surface waters.