Waste-to-resource strategy through green synthesis of PET-derived metal-organic frameworks for efficient photocatalytic dye degradation

Wastewater contaminated with dyes poses significant environmental and health hazards, including oxygen depletion and carcinogenesis. Photocatalytic technology offers a sustainable and efficient solution by harnessing abundant solar energy to drive chemical reactions, making it a cost-effective method for water treatment. Metal-Organic Frameworks (MOFs), known for their high surface area, porosity, and chemical tunability, are particularly promising materials for such applications. In this study, we developed a green synthesis method to repurpose polyethylene terephthalate (PET) bottles into terephthalic acid, which was then used to synthesize PET-MIL-101(Cr) (denoted as PM-101(Cr)). The synthesis process avoids the use of organic solvents such as HF or DMF to prevent secondary pollution. Further modification of PM-101(Cr) through nitration produced PET-NO₂-MIL-101(Cr) (PO-101(Cr)), which was subsequently reduced to form amine-functionalized PET-NH₂-MIL-101(Cr) (PH-101(Cr)). PH-101(Cr) demonstrated a dye removal efficiency of over 95 % within 4 h of blue light irradiation, surpassing the performance of PM-101(Cr). Additionally, after four catalytic cycles, PH-101(Cr) maintained a reduction efficiency above 95 % for 6 h, indicating its robust potential for effective dye treatment. In summary, PH-101(Cr) efficiently degrades methylene blue dye under blue LED light, achieving both waste recycling and environmental remediation for improved sustainability.