Metal-organic frameworks (MOFs) for adsorptive remediation of mono-aromatic volatile organic compounds (BTEX): a review

Abstract

Environmental pollution remains a front-burner issue in the realm of environmental sustainability pursuit, and monoaromatic volatile organic compounds (BTEX) are front-line culprits in this battle, especially in water bodies, which are the lifeline of all ecosystems. Interestingly, to eliminate these BTEX contaminants, metal-organic frameworks (MOFs) as multifunctional materials have come to the forefront among other emerging materials due to their high surface area, tunable porosity, functionalization, and coordinating capability. Thus, this study aims to review recent advances in the adsorptive removal of BTEX using MOFs. Remarkably, the highest reported adsorption capacity for BTEX is 3990 mg/g for MIL-101(Cr) in the removal of benzene. Moreover, modified/doped MOFs overperform their pristine counterparts in most cases. The key mechanisms for BTEX sequestration were observed to be coordination, H-bonding, pore filling, electrostatic, and π-π complexation/stacking/interactions. Most BTEX removal is spontaneous and favoured at room temperature and above, which is perfect for potential scaled-up operations. BTEX is effectively desorbed from expended MOFs using heat/methanol and is reusable for 3–10 cycles while still maintaining their original structural integrity and efficacy. Notably, while it can be concluded that MOFs are good for BTEX cleanup, future research might concentrate on exploring the scalability and integration of AI.