Ni-metal-organic-framework (Ni-MOF) membranes from multiply stacked nanosheets (MSNs) for efficient molecular sieve separation in aqueous and organic solvent

Abstract

Lamellar membranes are attracting extensive attention for high throughput and precise molecules/ions sieve separation. However, the energy-consuming exfoliation and low yield of single-layer nanosheets restrict the massive production of membranes. Herein, we facilely fabricated 2D Ni-mediated metal-organic framework (Ni-MOF) membranes directly from multiply stacked nanosheets (MSNs) for both aqueous and organic molecular sieve separation. Multiply layered nanosheets were obtained from a high concentration dispersion via simple ultrasonic treatment. The morphology and chemistry of synthesized Ni-MOF nanosheets were characterized via scanning electron microscopy (SEM), N2 adsorption-desorption, Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectra (XPS). The thickness of Ni-MOF membranes could be well regulated by the volume of dispersion. The membrane exhibited high molecular rejection to 8GX (97.29%), EB (96.28%), CR (99.69%), and CBB (93.31%) in water, respectively and a stable perm-selectivity in continuous 24 h filtration. The lamellar membrane showed excellent pressure and pH (2–10) resistance. The membrane achieved rational permeance of various organic solvents mainly depending on viscosity and good rejection to MB (91.37%), BY (92.01%), and EB (96.90%) in isopropanol.