Phosphorus Adsorption by Red Mud Based Al/Fe-MOFs Synthesized by Ultrasonic-Assisted Solvent Method: Performance and Mechanisms

Phosphorus (P) removal and the resource utilization of red mud(RM) critical environmental concerns. Red mud as a by-product of alumina production, constitutes a complex mixture of various valuable metals. In this study, a new Al/Fe-MOFs was synthesized using acid-leached RM via ultrasound-assisted solvothermal methods. The adsorption performance and mechanisms of the synthesized materials were systematically investigated. Results indicate that acid leaching of RM significantly enhanced adsorbent efficiency under various pH conditions and in the presence of competing ions. The phosphate adsorption process followed the Pseudo-second-order model and Freundlich models. Mechanistic analysis revealed a synergistic effect, with adsorption proceeding primarily through chemical adsorption and electrostatic interactions through the formation of surface hydroxyl groups.