MXene-bridged HMO/PSF adsorptive membrane for selective lithium recovery from shale gas wastewater with suppressed Mn leaching

Lithium recovery from shale gas wastewater (SGW) is essential for the growth of a sustainable economy. However, traditional powder adsorbents suffer significant loss and poor recyclability, limiting their practical utility. Here, we fabricate an HMO/MXene/PSF adsorptive membrane, in which 2D MXene serves as the hydrogen bond interacting agent between H 1.33 Mn 1.67 O 4 (HMO) and polysulfone (PSF). Notably, MXene incorporation effectively mitigates Mn leaching due to the hydrogen bond interaction. Efficient lithium recovery from Sichuan Basin SGW is achieved, with a lithium adsorption capacity of 21.18 mg/g. After ten consecutive cycles of adsorption and desorption, the HMO/MXene/PSF membrane shows remarkable cyclic stability, with a negligible decrease in lithium adsorption capacity of merely 0.16 %. Filtration studies reveal that the membrane with a surface area of 12.56 cm 2 can effectively filter 160 mL of SGW. The stability of the membrane due to hydrogen bond interactions and the selective adsorption mechanism are further confirmed through DFT calculations. This work presents a novel concept for constructing a mixed matrix membrane for lithium extraction from SGW and is expected to inspire further efforts in developing LIS-based adsorbents for lithium recovery.