“Sea Anemone”-like CeFe Oxides for High-Efficient Phosphate Removal

Abstract

The excessive release of phosphorus is a prime culprit for eutrophication and algal bloom in the aquatic environment, and there is always an urgent need to develop effective methods to deal with phosphorus pollution. Ce-based oxide is a type of compelling adsorbent for phosphate removal, and a self-templating strategy is used to construct high-performance Ce-based oxides for phosphate adsorption in this study. A “sea anemone”-like CeFe cyanometallate (CM) with a 3D microstructure is fabricated to provide a precursor for synthesizing CeFe-based oxides (CeFe-CM-T) by high-temperature pyrolysis. The as-prepared CeFe-CM-T maintains the “sea anemone” morphology well and has abundant micropores/mesopores, which render its superior phosphate adsorption capacity 1~2 orders of magnitude higher than that of the commercial CeO2 and Fe3O4 materials. Moreover, CeFe-CM-T shows high selectivity for phosphate removal when it co-exists with other anions and natural organic matter and exhibits excellent recycling performance. It demonstrates that both Ce3+ and Ce4+ are reserved in the oxides, where Ce3+ serves as the main active site for phosphate capture, which forms stable Ce-PO4 compounds via a ligand-exchange mechanism. Thus, the self-templating strategy using CM as a precursor is a potential method for synthesizing porous Ce-based oxides for phosphate removal.