Constructing a low-cost total Ce(III)-based adsorbent for efficient removal and recovery of phosphate

Under the dual challenges of water eutrophication and phosphorus deficiency, efficient adsorbents are urgently needed to remove and recover excess phosphate. However, the highly regarded cerium-based adsorbent has become the main difficulty limiting its large-scale application due to its high energy consumption and uncontrollable valence state in the synthesis process. To address this issue, we synthesized a composite cross-linked framework adsorbent (CCFA) using a simple coprecipitation method for application as a novel phosphate trap. Due to the realization of 100 % Ce(III) acquisition, CCFA exhibited a high adsorption capacity of up to 289.18 mg-P/g·Ce, 1.5 to 2 times higher than existing cerium-based adsorbents. At the same time, the introduction of sepiolite not only improved the utilization efficiency of the active sites, resulting in a high P/Ce molar ratio of 1.31, but also enhanced the resistance to pH interference, with the adsorption capacity only decreasing by 16.5 % in the presence of strong alkali (pH = 11). In addition, CCFA exhibited a wide range of adaptability, excellent phosphate recovery potential, and the prospect of large-scale application, making it a promising adsorbent for wastewater phosphate.