Efficient macroporous adsorbent for phosphate removal based on hydrate aluminum-functionalized melamine sponge

Effective removal of phosphate from aqueous solution is of great significance in environmental protection. In this paper, the concept of developing a hierarchical and cost-effective aluminum functionalized melamine foam (MF) as phosphate adsorbent is presented. The material with 3D interconnected network, flexibility and ultralow density was fabricated via a simple adsorbing method based on hydrate aluminum and commercially available MF sponge. For use as an adsorbent, performance of the as-prepared MF-HA sponge was assessed with various pH, temperatures, adsorption time, initial P concentrations, ionic strengths and co-existing ions. The experimental results demonstrated that MF-HA performed well in a wide pH range of 4–10 and in the presence of foreign anions, with high maximum uptake capacity of 36.21 mg P/g. Furthermore, for the as-prepared material, the phosphate removal performance at different temperatures established the endothermic nature of the adsorption process. Moreover, MF-HA sponge could be directly separated from the solution and showed a satisfactory recyclability. The adsorbing strategy to design and fabricate the novel sponge with resultant high adsorption efficiency, cost-effectiveness, preferable selectivity, environmental friendliness, and easy separation from water may promote sponge functionalization for applications in extensive wastewater treatment areas.