Polyaniline-modified metal-organic frameworks for simultaneous sorption of UO22+ and ReO4- from water

The efficient simultaneous extraction of radioactive metal cations and anions from radioactive waste is crucial for the proper disposal of spent fuel and environmental protection. Modifying metal-organic frameworks (MOFs) into multifunctional materials with tailored properties offers a promising strategy to enhance their practical applications. In this study, polyaniline (PANI)-modified MOF nanosheets (NM53P) are synthesized through a simple, low-cost method and employed to uptake uranium (UO 2 2+ ) and rhenium (ReO 4 - ) from aqueous solutions. The adsorption performance of NM53P-3 composites is evaluated by studying the effects of solution pH, contact time, initial UO 2 2+ /ReO 4 - concentrations, ionic strength, and interfering ions. The maximum adsorption amounts for UO 2 2+ and ReO 4 - are 293.91 and 526.32 mg/g, which surpass most reported adsorbents. Adsorption of UO 2 2+ /ReO 4 - is pH-dependent, spontaneous, and endothermic, and best fit the pseudo-second-order (PSO) kinetic model and Freundlich isotherm. Batch experiments and X-ray photoelectron spectroscopy (XPS) analysis confirm that adsorption is primarily influenced by the abundant amine functionalities and unsaturated metal sites in the NM53P-3 adsorbents. Furthermore, NM53P-3 demonstrates excellent recycling performance. This study highlights the potential of NM53P-3 composites for effectively extracting various radionuclides from aqueous solutions, paving the way for the development of new multifunctional materials for wastewater treatment.