Efficient waste polyester plastics recycling in organic-inorganic acid catalytic system

To solve the growing waste plastics problems, we herein reported an efficient method for polyester plastics recycling under mild conditions (<100 degrees C) by using formic acid (FA) and tungsten-based polyoxometalate (phosphotungstic acid, PW12) as the organic-inorganic catalyst system. PW12 is crucial for the efficient catalytic hydrolysis of polyester bonds through nucleophilic attack of the carbonyl carbon of the ester group by highly negative charged terminal oxygen atoms of PW12. The experimental results and molecular dynamics (MD) simulation verified that FA has a good swelling effect and dispersion ability on polyester, which highly accelerates the cracking reaction. Due to the synergetic effect between FA and PW12, practical waste plastics (PET/PBT) from colored bottles or woven fibers can be completely decomposed to yield highly purified TPA and ethylene glycol (EG)/1,4-butanediol (BDO). ASPEN Plus simulations and life cycle assessment (LCA) demonstrate that this organic-inorganic catalyzed method provides a low-carbon economical way to achieve the comprehensive recycling of waste polyester.