Waste-to-MOF: Sustainable Microwave Fabrication of MIL-53(Al) MOF Using Reclaimed PET and Industrial Aluminum Dross Waste for CO2 Sorption Application

Grey aluminum dross, a byproduct of aluminum smelting and recycling, finds applications in several sectors; however, its applications are still limited. Metal-organic frameworks (MOFs) are porous materials comprised of metal nodes and organic linkers. MOFs have pore size and shape control, large surface area, and structural stability, among other qualities that make them versatile for a variety of uses. MIL-53(Al) MOF was successfully synthesized by microwave synthesis utilizing polyethylene terephthalate (PET)-derived BDC and acid leachate from grey Al dross waste. Under microwave radiation, the complete coordination of Al metal clusters and BDC (benzene dicarboxylic acid) linker generated from PET took place in 60 min. The structures and characteristics of the grey dross solid waste and the synthesized materials were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), Fourier-transform infrared spectrometry (FTIR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET). The waste-derived MOF was also assessed as an adsorbent for CO2, a gas that is widely produced by industrial processes and a significant cause of environmental issues. The waste-derived MIL-53(Al) showed the CO2 uptake capacity of 1.39 mmol/g (1 atm, 25 °C). The material demonstrated encouraging CO2 adsorption capabilities, highlighting its potential as a sustainable sorbent. This strategy upcycles industrial and plastic waste into useful materials with added value, addressing environmental issues and the circular economy concepts.