Competitive adsorption of As(V) with co-existing ions on porous hematite in aqueous solutions

Effects of co-existing ions on the adsorption of As(V) in aqueous solutions by porous hematite have been investigated in this work. The porous hematite was prepared by the goethite concentrate which was concentrated from the iron oxide tailings. The co-existing ions include Cl−, NO3−, HCO3−, SO42−, PO43− anions and Na+, K+, Mg2+, Ca2+. The arsenic aqueous solutions with these co-existing ions were simulated using chemical reagents and deionized water. The adsorption isotherm and kinetics were all examined. The experimental results showed that HCO3− and PO43− anions inhibited the As(V) adsorption, whereas Mg2+ and Ca2+ ions have promoting effects on the As(V) adsorption. Furthermore, the ionic strength has no significant effect on the arsenate adsorption to the porous hematite. These results may be attributed to competitive adsorption of As(V) on porous hematite in aqueous solutions.