Upcycling of Dyed Polyester Fabrics into Copper-1,4-Benzenedicarboxylate (CuBDC) Metal–Organic Frameworks

Abstract

We report on a pathway to synthesize metal–organic frameworks (MOFs) using discarded textiles as a raw material. Discarded objects made of poly(ethylene terephthalate) (PET) could be an inexpensive and globally available source for 1,4-benzenedicarboxylic acid (H2BDC), also known as terephthalic acid, a building block of carboxylate-based MOFs. Previous studies on using discarded PET to synthesize MOFs have mainly focused on PET bottles. In contrast, we demonstrate the use of dyed polyester fabrics as a raw material. Specifically, we report on a synthesis path for copper-1,4-benzenedicarboxylate (CuBDC) utilizing disodium terephthalate (Na2BDC) as a linker and on how we obtained the linker from depolymerized polyester fabrics. To facilitate coordination between the copper ions and Na2BDC and create a localized acidic environment that favors the synthesis of CuBDC MOFs rather than metal oxide byproducts, we added acetic acid to the copper precursor solution. The drop-sized pH-controlled domain enabled the formation of CuBDC MOF crystals at room temperature and at a fraction of time shorter than traditional solvothermal methods. We confirmed the resulting MOF structures using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy, and our results were in quantitative agreement with previous reports. Furthermore, we used different copper salts as metal sources and different color-dyed polyester fabrics as linker sources, demonstrating the versatility of the proposed synthesis path. These results may open an avenue for using discarded textiles as a raw material and offer a more circular approach for managing textile waste.