A novel nanostructured Fe-Ti-Mn composite oxide for highly efficient arsenic removal: Preparation and performance evaluation

Abstract

Co-existing of arsenate (As(V)) and arsenite (As(III)) in aquatic environment have posed a great threat to humans due to the high mobility and toxicity. Developing practical methods for the removal of arsenic contamination in water source is vital for improving human wellbeing. Here, a novel nanostructured Fe-Ti-Mn composite oxide (FTMO) for the efficient removal of arsenic was synthesized using a simultaneous oxidation and co-precipitation method. The adsorbent was amorphous or poorly crystallized and was aggregated from heterogeneous nano-sized particles, with a high specific surface area of 434.3 m2/g. Batch experimental results showed that the FTMO effectively removed both As(V) and As(III), and the maximal adsorption capacities of arsenic species at 25 °C were 74.4 mg/g (As(V)) and 122.3 mg/g (As(III)), respectively. The arsenic removal process was endothermic and spontaneous, and the uptake of arsenic was highly pH-dependent. The inhibitive influence of competitive substances on the adsorption behavior followed by the order of: SO42− < Cl- < F- < HCO3- < SiO32− < PO43-. The presence of Ca2+ and Mg2+ slightly enhanced the arsenic removal. Moreover, the FTMO material could be effectively regenerated and successfully applied for arsenic removal in simulated As-contaminated river water treatment. Thus, the oxide could be used as a potentially attractive adsorbent for arsenic removal from contaminated water because of its easy synthesis process and excellent adsorption performance.