Selective removal and recovery of La(III) using a phosphonic-based ion imprinted polymer: Adsorption performance, regeneration, and mechanism

It is significant and difficult to selective removal and recovery rare earth elements in wastewater. A novel La(III) imprinted polymer (La-IIP) was synthesized by taking advantage of the strong interaction between Lanthanum and phosphorus combined the adsorption selectively of ion imprinted technology. The adsorption capacity of La-IIP is 62.8 mg g–1 and the selectivity coefficient kLa/Cu is 54.57. La-IIP can reach adsorption equilibrium within 0.5 h, the adsorption process was well revealed by the Intra-particle diffusion model. The regeneration properties (desorption rate, extent, and recycle times) of La-IIP were investigated. About 88% of the adsorbed La(III) was desorbed in the first 10 min. The high desorption rate was further confirmed in a fixed-bed column experiment. More significantly, the removal efficiency of the La-IIP remained about 100% after five regeneration cycles. Results of FT-IR, XPS, and DFT calculation indicated that the La(III) adsorption by La-IIP involves the reaction between La and O in the phosphonic group. This study not only demonstrated a high adsorption capacity, acid-stable, quick-desorption, and reusable adsorbent for La(III) recovery, but also developed a more comprehensive strategy for the design and testing of adsorbents with practical application prospects.