Conversion of Polyethylene Terephthalate Plastic into Metal-Organic Framework Materials for the Adsorption of Organic Dyes

Metal-organic frameworks (MOFs) are a class of materials with highly crystalline structures that are frequently utilized for the adsorption of organic dyes such as methylene blue (MB). The conversion of polyethylene terephthalate (PET) plastic to terephthalic acid in MOF synthesis represents a novel and promising “waste to MOFs” approach to utilize the vast amount of PET wastes. In this study, MIL-53(Al) was synthesized from waste PET plastics via a one-step hydrothermal process using water as the solvent, with the highest PET processing efficiency of 71.252% at 200°C, solvent volume of 2 L and material/solvent ratio of 9.4 g/mL. The highest PET to MOF conversion efficiency reached 99.2% at 198°C, solvent volume of 5.5 L and material/solvent ratio of 19.6 g/mL. Although the synthesized MOF material had a low BET surface area of 0.4463 m 2 /g due to inefficient washing and activation processes, it exhibited a maximum adsorption capacity of 12.16 mg MB/g after optimization. This opens up a potential direction in converting waste PET plastics into MOFs by a simple, inexpensive, convenient and environmentally friendly method, which can be applied for many purposes such as adsorption of organic dyes.