Low-Cost Goethite Nanorods for As (III) and Se (VI) Removal from Water

Arsenite (As(III)) and Selenate (Se(VI)) are universally touted as extremely toxic oxyanions in natural and industrial water systems. Thus, the production of low-cost adsorbents that are scalable and toxic-free is of great importance today. In this work, a large-scale goethite nanorods (alpha-FeOOH NRs) is synthesized using a modified rapid hydrolysis method. The obtained powder is characterized using different multidisciplinary techniques. Accordingly, the results showed uniform and straight nanorods (length similar to 400 nm and diameter similar to 40 nm) resembling cigar-like morphology while the structure is confirmed to be of orthorhombic alpha-FeOOH phase. The potential application of this material to adsorb As (III) and Se (VI) ions in water is explored. In particular, for initial adsorbate concentrations (similar to 500 mu g/L), the removal efficiencies are found exceptional with alpha-FeOOH doses of 0.33 g/L and similar to 0.5 g/L for As (III) and Se (VI), respectively. Attractively, the adsorption capacities were estimated using trusted isotherms and then experimentally verified at ultimately high concentrations. Besides, a pH-controlled adsorption study showed that a pH of 5-8 is a favored range for higher ionic uptake, which meets the World Health Organization (WHO) benchmarks of drinking water. To conclude, the alpha-FeOOH NRs are potential adsorbent for the sustainable removal of toxin ions in water systems.