High-performance ZIF-8 membranes: preparation and their uranium adsorption performance

In this study, the ZIF-8 membrane (ZIF-8/PP-g-MAH) is prepared by in situ synthesis of ZIF-8 on irradiation-pretreated polymer substrates to improve the uranium adsorption performance and address the recycling problems of ZIF-8 powder. The effects of pH, contact time, and uranium concentration on the adsorption of ZIF-8/PP-g-MAH were investigated. Adsorption isotherm and kinetics analysis show that ZIF-8/PP-g-MAH has a high adsorption capacity of 478.5 mg/g, which is 1.26 times higher than that of ZIF-8, and a rapid adsorption equilibrium of 120 min, which is shortened to one-third of that required for ZIF-8 (360 min). The adsorption process of ZIF-8/PP-g-MAH is consistent with that of the Langmuir isotherm and pseudo-second-order dynamic model. ZIF-8/PP-g-MAH also exhibits good selectivity for uranium in simulated seawater. The high adsorption performance of ZIF-8/PP-g-MAH is attributed to its membrane structure, which improves the utilization of coordination sites, including Zn-OH, C-N, and C=N. This study provides an efficient adsorption material for rapid uranium extraction, thus promoting the development of uranium extraction technologies.