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

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 effi-ciency. 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. (c) 2021 Published by Elsevier B.V.

Automated summary

The synthesized Fe-Mn-Ca composites show excellent adsorption performance for high concentrations of As(III)-contaminated water, with the presence of a higher ratio of Ca component leading to larger specific surface area and better removal efficiency. EDTA-conjugated Fe-Mn-Ca composite adsorbents exhibit enhanced affinity for As(III) over As(V) in high ionic strength water. This promising adsorbent offers outstanding characteristics for treating high-concentration arsenic wastewater in practical industrial applications.