ABSTRACT
The Donnan Membrane Effect was used to design a novel As and fluoride sorbent using a polymeric anion exchange resin. Where counterions present in the aqueous phase, e.g., As and fluoride, will be concentrated within an anion exchange resin phase. Inside the anion exchange resin, oxides of polyvalent metals, namely, Fe(III) and Zr(IV) were desired because they are known to exhibit ligand sorption properties through formation of inner-sphere complexes. Hydrated iron and zirconium oxides (HFOs and HZOs, respectively) are ideal sorbents from a chemical and economical perspective: stable over a wide pH range, innocuous, available globally at a moderate price and exhibit high sorption affinity for Lewis bases, e.g., As, F, and no affinity towards nonLewis bases, e.g., SO42-, Cl-. The hybrid of a strong polymeric anion exchange scaffold that utilizes the Donnan Effect to attract trace ions of concern with nanoparticles of HZOs creates the HAIX-Nano resin for efficient As and fluoride removal. Equally important, HAIX-Nano stability makes it amenable to efficient regeneration and reuse (Cumbal & SenGupta, 2005, Padungthon et al., 2015).
