With the ever-increasing of Rare Earth Elements (REEs) in various high technology applications, efficient recovery of REEs from liquid sources is becoming significantly important. In this work, ZIF-8 and UiO-66-NH 2 (U6N) are combined to form a 3D-agaric like core-shell structure hybrid material (U6N@ZIF-8-20), which exhibits good performance in REEs extraction. Due to the abundant adsorption sites of ZIF-8 and the excellent water stability of UiO-66-NH 2 , 3D-agaric like U6N@ZIF-8-20 showed quick adsorption rate (only 10 min to reach equilibrium), high adsorption capacity and selectivity for REEs from water compared to other reported adsorbents. Maximum adsorption capacities of U6N@ZIF-8-20 for neodymium (Nd(III)), europium (Eu(III)), gadolinium (Gd(III)) and erbium (Er(III)) achieved to 249.90, 295.28, 316.22 and 340.95 mg g -1 , respectively. U6N@ZIF-8-20 has superiority in selective adsorption of REEs from Cd(II), Zn(II), Cu(II), Mn(II) and Co(II) coexistence solution. The order of adsorption capacities for REEs is in agreement with the order of their electronegativity, ionic radius and charge density. Moreover, U6N@ZIF-8-20 showed better water stability and recyclability than single MOF. Overall, MOF@MOF hybrid material has efficiency in REEs separation from solutions, and has great advantage in the application of wastewater treating.
The management of rare earth elements (REEs) from mining wastewater has consistently a key issue. Our previous research has demonstrated the selective adsorption of REEs in mining wastewater by ZIF-8. Herein, one-step pyrolysis of ZIF-8 after recovering REEs from mining wastewater as a high-value product was further proposed. The resulting REEs-based magnetic nanoporous carbon materials (REEs-MPC) was utilized for the activation of peroxymonosulfate (PMS) in the removal of bisphenol A (BPA). Experimental results indicate substantial BPA removal efficiencies of 74.62 %, 83.57 %, and 70.06 % with REEs-MPC synthesized at different pyrolysis temperatures (700 °C, 800 °C, and 900 °C). The detailed characterizations reveal the REEs-MPC at 800 °C was obtained (REEs-MPC/800) exhibit prominent graphitic and defective characteristics. In addition, electrochemical analysis revealed that the REEs-MPC/800 demonstrate elevated conductivity and superior capacitive current, with Tafel slopes as high as 294 mV/dec. Functional theory (DFT) calculations demonstrate that the presence of graphitic-N and REEs-N species significantly enhance PMS activation. Finally, a neural network model constructed through machine learning techniques provided a comprehensive overview of the structure–property relationship. Overall, the proposal to synthesize a high-value product using mining wastewater has been put forward. This initiative is expected to contribute to the advancement of the green economy within the rare earth mining industry.
危险品化学品经营许可证（带存储）