Selective and efficient removal of As(V) and As(III) from water by resin-based hydrated iron oxide

Arsenic pollution in natural water is a worldwide problem. In this work, a resin-based hydrated iron oxide (D303-HFO) adsorbent was designed to remove arsenate (As(V)) and arsenite (As(III)) in the groundwater. The structure and morphology of the D303-HFO adsorbent were characterized by FTIR, XRD , SEM and TEM tests. The specific surface area, pore volume and pore size increased with the incorporation of HFO nanoparticles in the resin. In addition, the effects of pH and coexisting ions on the arsenic removal efficiency were investigated. Results indicated that the D303-HFO had efficient removal performance for arsenic in the pH range of 3–9 and showed high selectivity for As(V) and As(III) under the influence of competitive ions. The adsorption kinetics study confirmed that the adsorption process was dominated by chemisorption , and the adsorption isotherms of As(V) and As(III) by D303-HFO fitted the Langmuir model. Thermodynamic parameters indicated that the adsorption reaction was spontaneous and exothermic. Moreover, the regeneration and stability experiment indicated that the D303-HFO adsorbent was super reusable after five consecutive cycles and could be put into service stably and permanently. The fixed-bed column test showed that the water sample containing As(V) and As(III) was treated with a volume of 900BV and 1100BV, respectively. After the treatment, the effluent concentration reached the drinking water standard stipulated by WHO.