18-Crown-6-ether assembly of cesium ion-imprinted polymer enabling efficiently selective separation of cs(I) from aqueous solution

In this study, a cesium ion imprinted polymer (Cs(I)-IIP) was prepared by free radical thermal polymerization using 18-crown-6-ether (18C6) as ligand, methacrylic acid (MAA) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent, which can be used for adsorption and separation of cesium ions from low-concentration solutions. The adsorption kinetic and isotherm results showed that the adsorption of Cs⁺ fitted to the pseudo-second-order kinetic model and Langmuir model, indicating that the adsorption of Cs⁺ on Cs(I)-IIP was the monolayer chemical adsorption. The maximum adsorption capacity was 84.21 mg·g^− 1. The selective adsorption properties are performed in Cs⁺, Li⁺, Na⁺, and K⁺ multicomponent systems. The results showed that the Cs(I)-IIP has a high selectivity in the presence of coexisting Li⁺, Na⁺, and K⁺, and the selectivity coefficients (K’) of Cs(I)-IIP for Cs⁺/Li⁺, Cs⁺/Na⁺, Cs⁺/K⁺ are 2.1, 1.56, and 1.33, respectively. The high adsorption capacity and selectivity are attributed to the introduction of imprinting technology to form specific Cs⁺ recognition adsorption sites, and the 18C6 cavity was easier to recognize Cs⁺ in the competitive adsorption process. Finally, the Cs(I)-IIP can be regenerated and reused for 10 times with the adsorption capacity only decreased by 8.1%, indicating that the polymer has good reuse performance.