Recycling of stainless steel pickling wastewater and polyethylene terephthalate plastic: A total-waste synthesis of metal-organic framework

Metal-organic frameworks (MOFs) attract considerable interests in various fields while relatively high cost limits their industrial-level use. Herein, we proposed a total-waste preparation route for Fe/Cr-MIL-88B (MIL, Matérial Institut Lavoisier), in which stainless steel pickling wastewater (PW) and waste polyethylene terephthalate (PET) act the total raw materials. Interestingly, PET is easily decomposed to terephthalic acid (H2BDC) under the strong acid environment of PW. Benefited from that, the formation of MOFs from PET and PW can be achieved via one-pot hydrothermal reaction, superior to the traditional two-step method. The obtained MIL-88B exhibits long-term acid/base stability and high removal efficiency for zirconium (IV) ion. Besides, the structure and adsorption performance of the products are not controlled by the discharge batch of the pickling wastewater, indicating the feasibility for continuous production in industry. Thus, our work provides a feasible route for preparing low-cost MOFs and recycling industrial wastes.