Ultrafast Molecular-Sieving Graphene Oxide Membranes for Selective Separation of Volatile Aromatic Compounds

Ultrafast molecular-sieving graphene-based membranes with selective separation of volatile aromatic compounds (VACs) have great potential in environmental protection, reutilization of expensive materials, and industrial separation processes. However, current graphene-based absorbents suffer from slow removal speed and limited adsorption capacity for VACs. Herein, pristine and Ni2+-controlled graphene oxide membranes (GOMs) with a permeance up to ∼8.0 × 10–6 mol m–2 s–1 Pa–1, being 1–2 orders of magnitude higher than those of previously reported membranes. The GOMs selectively separate VACs from N2 is achieved on ceramic substrates via the size-exclusion effect for the first time. At a high VACs feed concentration, such GOMs show high rejection rates of 99.8, 99.4, 95.9, and 97.3% for phenol, benzaldehyde, benzoic acid, and benzylamine, respectively. X-ray diffraction (XRD) results show the two-dimensional (2D) channel size for gas transportation within the GOMs is 0.44 nm, which can reject the transportation of VACs but have no effect on N2. Interestingly, using improved Ni2+-controlled GOMs, the rejection rates of benzoic acid and benzylamine rejection rates increased from 95.9 to 98.6% and from 97.3 to 99.4%, respectively. Our finding provides a fast and efficient way to filter VACs in air and has potential applications in air purification and industrial processes.