Enhanced catalytic aminolysis of polyethylene terephthalate plastic wastes via zeolite acid–base site regulation

Abstract

The catalytic aminolysis of polyethylene terephthalate (PET) plastic wastes to the value-added diamine products plays an increasingly significant role in sustainable environmental and energy development. Herein, an Na-ZSM-5-70 zeolite was fabricated through the incorporation of metal ions to regulate acid–base sites, which could efficiently catalyze the aminolysis of PET plastic to bis(2-hydroxyethylene)terephthalamide (BHETA) with a separation yield of up to 98.1%. The characterization analysis displayed that the introduced Na⁺ could exchange with the protons in silanol groups and remove the silicon adjacent to aluminum, which contributed to more basic and acidic sites, respectively. The regulated acid–base sites had a synergistic effect on the successive aminolysis of PET plastic wastes to BHETA. Ultimately, various PET plastic wastes and aminolyzed agents were applied for efficient catalytic aminolysis to the corresponding diamine products, affording a new perspective for the efficient upcycling and utilization of PET plastic wastes.