Arsenic removal from aqueous solutions by adsorption onto hydrous iron oxide-impregnated alginate beads

Hydrous iron oxide impregnated alginate beads were developed for effective arsenic removal from water. As(III) adsorption was maximized at neutral pH while As(V) adsorption was higher in acidic conditions. Adsorption efficiency for both As(III) and As(V) mostly increased with increasing iron loading, but As(V) adsorption slightly decreased at high iron loading. Phosphate showed a pronounced interfering effect, especially at high concentration. Kinetics data fitted to pseudo-second-order and intra-particle diffusion model suggested chemisorption and intra-particle diffusion might mainly govern As(III) and As(V) adsorption, respectively. Beads were regenerated using NaOH solution and successfully reused for multiple cycles.