Highly efficient removal of As(III) by Fe-Mn-Ca composites with the synergistic effect of oxidation and adsorption

Highlights: • A novel Fe-Mn-Ca adsorbent was prepared for removing high-concentration As(III). • Fe-Mn-Ca composite exhibits superior As(III) removal capability and reusability. • The optimal reaction conditions for As(III) removal were determined. • As(III) removal was attributed to a synergy effect of adsorption and oxidation. • Calcium component on Fe-Mn-Ca adsorbent promotes oxidation during the reaction. Developing highly effective and low-cost adsorbent is crucial for removing the more toxic arsenic wastewater. However, most of the adsorbents cannot meet the requirements for adsorbing high concentrations As(III) sewage. Here, we report the as-synthesized Fe-Mn-Ca composites with excellent adsorption performance for the treatment of high concentrations As(III)-contaminated water. It is found Fe-Mn-Ca composite with higher ratio of Ca component exhibits larger specific surface area and zeta potential, which receives a better removal efficiency. Consecutive adsorption recycling experiments demonstrate that Fe-Mn-Ca composites have remarkable reusability performance. FTIR and XPS results reveal that As(III) removal by Fe-Mn-Ca composites was attributed to the synergistic effect of oxidation and adsorption process. The calcium component on the adsorbent particles may promote the derivatization of hydrogen peroxide, resulting in more arsenite being converted to arsenate ions and thus achieving an excellent adsorption capacity. This work provides a promising adsorbent with outstanding adsorption properties toward the treatment of high-concentration arsenic wastewater in the practical industrial application.