A Circular Life-cycle Paradigm for Bio-derived Dual-ligand Cu-MOFs: from Scalable Manufacturing to Greenhouse Gas Mitigation

Abstract

Despite the significant potential of metal-organic frameworks (MOFs) in capturing greenhouse gases, their industrial implementation is hindered by hazardous synthesis conditions, suboptimal pelletisation, low atomic efficiency, and expensive waste treatment. Herein, a cradle-to-cradle sustainable protocol is proposed for bio-based dual-ligand Cu-MOFs, encompassing the entire life cycle from green and scalable synthesis, shaping, service, to material reconstruction and waste recycling. Using a quasi-aqueous water-ethanol solvent, a representative Cu-MOF, BUT-321, was manufactured at the kilogram scale with a high yield (98%). Featuring favourable SF₆ and CO₂ affinity, this MOF demonstrates considerable SF₆/N₂, CO₂/N₂, and CO₂/CH₄ separation performance. Furthermore, spherical BUT-321 pellets with intensified mechanical strength were fabricated using a green binder, hydroxyethyl cellulose (HEC), retaining > 90% of the gas uptake of the pristine powder. Eventually, the deteriorated MOF pellets were readily reborn under modest conditions in reclaimed waste supernatants, with their physicochemical properties fully restored. This work not only delivers a high-performance adsorbent for greenhouse gas capture but also establishes a green and viable paradigm for the circular utilisation and waste valorisation of MOFs, promoting their industrial deployment.