Electrochemically regulated cerium-based electrode for enhanced phosphate adsorption and desorption process
Abstract
Cerium-based materials have great potential in adsorbing phosphates and treating water pollution. However, metal-based adsorbents often face challenges like poor stability and difficulty in recycling. Herein, efficient phosphate adsorption and recovery were achieved by preparing a cerium hydroxide-based electrode and using an electroreduction/oxidation strategy to regulate the valence state of the Ce element. The adsorption and desorption characteristics, mechanism, and cyclic stability of cerium hydroxide-based electrodes were further investigated. The results showed that the removal of phosphate by cerium hydroxide-based electrode after electrochemical reduction conforms to pseudo-second-order kinetics, and the phosphate adsorption capacity is as high as 98.7?mg/g, which is 1.53 times that of the original cerium hydroxide-based electrode. The high proportion of Ce3+ species produced by electro-reduction significantly improves the adsorption performance. After electro-oxidation regulation, the cerium hydroxide-based electrode with a higher proportion of Ce4+ can obtain an excellent desorption rate and desorption capacity while reducing the concentration of NaOH desorption solution. At the same time, the highly reversible redox characteristics give the cerium hydroxide-based electrode excellent reusability. This cerium hydroxide electrode material based on redox regulation strategy has excellent recyclability and cycle stability, which significantly improves the practicality of Ce-based phosphate adsorption materials.