Assembly of Porous Monolithic Materials Using a Pickering Emulsion Strategy Stabilized by Metal-Organic Framework...

Metal-Organic Frameworks (MOFs) are highly porous, crystalline materials of great interest for applications ranging from gas adsorption to catalysis. However, the industrial scalability and application of MOF powders are hindered by the challenge of finding a shaping method that preserves their inherent porosity and surface chemistry. Traditional techniques often compromise these crucial properties through mechanical stress or the use of pore-blocking binders. This study presents a protocol for the assembly of mechanically robust, hierarchically porous monolithic materials using MOF particles as stabilizers for Pickering emulsions. The goal of this work is to overcome the limitations of MOF shaping by utilizing an emulsion-based template method, thereby yielding a solid structure that is macroporous and retains accessible MOF microporosity. The protocol involves synthesizing MIL-96(Al), an aluminum-based MOF, using a sustainable method by using recycled Li-ion battery waste as metal sources. This MOF is then used to stabilize high internal phase Pickering emulsions (HIPE). Upon solidification, the emulsion template yields macroporous monoliths. The incorporation of Polyvinyl alcohol (PVA) or polymer precursors into the aqueous phase is shown to be decisive. Their addition significantly reduces droplet sizes and enhances pore interconnectivity (PolyHIPE). The resulting monoliths retained the MIL-96(Al) framework's integrity, confirmed by XRD and FTIR. While some inherent loss of microporosity occurs during the process, the careful tuning of PVA concentration allows control over pore morphology and enhanced permeability, demonstrating that MOF/polymer monoliths competitive with literature standards can be obtained. This strategy offers a promising route for the scalable shaping of MOFs for applications in fluid processing and adsorption.