Magnetic Metal–Organic Frameworks (MOFs) from Waste: A Solvent-Free Rapid Synthesis of Green Catalyst for Environmental Cleanup
Preeti Waribam, Thilina Rajeendre Katugampalage, Makoto Ogawa, Pakorn Opaprakasit, Wanida Chooaksorn, Pat Sooksaen, Pathompong Puathawee, Paiboon Sreearunothai
Abstract
High Resolution Image Download MS PowerPoint Slide Recycling waste polyethylene terephthalate (PET) and heavy-metal-containing industrial wastewater to produce metal–organic frameworks (MOFs) offers a sustainable solution that reduces environmental pollution via waste upcycling. PET bottles were depolymerized into sodium terephthalate linkers (Na-BDC) via a solvent-free ball-milling process, resulting in Na-BDC linkers with 94% purity. The Na-BDC linkers were further reacted with iron-rich wastewater in a solvent-free microwave-assisted reactor for 30 min, rapidly forming a magnetic MOF composite (MagMOF). The proposed synthetic route is novel, solvent-free, environmentally friendly, time-efficient, and scalable. MagMOFs showed strong magnetic properties essential for catalyst recovery using an external magnetic field. The unsaturated metal sites and Fe III /Fe II redox pairs observed in the structure directly influenced the high catalytic activity. Near complete degradation of azo dye was observed in 30 min via Fenton-like catalysis at a slightly acidic pH. The degradation efficiency of the spent MagMOF_300 retained 84% even after 5 consecutive reuse cycles, showcasing its robustness and structural stability. Integrating ball milling with rapid microwave-assisted MOF synthesis in this work offers a greener, energy-efficient, and scalable platform for converting industrial waste into value-added functional materials, supporting sustainable close-loop-recycling.