Advancing phosphate Removal: Unleashing the Adsorption/Desorption potential of La2(CO3)3-Loaded resin by Semi-Fluidized columns and In-Situ regeneration

Abstract

Phosphate removal and recovery from contaminated water are crucial in addressing eutrophication and global phosphorus (P) scarcity. Conventional adsorption reactors and adsorbent regeneration techniques fall short of meeting the demands for efficient phosphorus removal and recovery. This study, for the first time, presents a semi-fluidized reactor using La2(CO3)3-loaded anion-exchange resin (LC@AER) for enhanced phosphorus removal and in-situ adsorbent regeneration. The response surface methodology (RSM) analysis identifies the ideal conditions for optimizing adsorption efficiency and highlights the substantial influence of pH and sulfate concentration on the phosphate adsorption capacity. The Thomas and Yoon-Nelson models exhibit excellent fits with breakthrough curves (R2>0.99), facilitating the determination of the adsorbent dosage for practical applications. In the semi-fluidized reactor, LC@AER performs efficiently in five adsorption–desorption cycles with an average adsorption capacity of 44.67 mg/g and a regeneration efficiency of 92.22%, achieving enhancements of 86.8% for phosphate adsorption and 61.22% for adsorbent regeneration (compared with fixed-bed columns using LC@AER). These results demonstrate that the semi-fluidized reactor enables LC@AER to achieve excellent reusability, ensuring its promising industrialization prospects. The enhanced performance is attributed to the semi-fluidized reactor offering better interaction between the adsorbent and liquid and overcoming issues of the dead zone and channeling. This study has substantial significance for sustainable phosphorus pollution management and provides key parameters for potential industrial-scale applications of this process.