Recovery of Phosphate from Aqueous Solutions Using Self-Organized Iron Oxide Nanotubes

The use of nanomaterials in wastewater treatment has attracted a growing amount of attention due to the excellent electrical, magnetic, and catalytic properties of nanomaterials. In this study, we fabricated iron oxide nanotubes (INTs) for phosphate recovery in wastewater. The formation of nanotubes and various complexes of iron oxides were investigated by surface analysis techniques (FE-SEM, AFM, and XRD). A pseudo secondorder model simulated the experimentally observed phosphate adsorption on INTs well. We found that the Langmuir isotherm model was more suitable than the Freundlich model for describing phosphate isotherms on INTs. Changes in temperature and pH had a significant effect on adsorption efficiency, while NaOH solution desorbed the adsorbed phosphate on the INTs. Although the maximum adsorption capacity of INTs was lower than that reported for other iron oxide particles, INTs are useful to recover phosphates in wastewater because additional collection of adsorbents is unnecessary and industrial byproducts can be used as raw materials to prepare INTs.