Alkali-catalyzed hydrolysis effectively depolymerizes waste polyesters and recovers high-purity monomers. Nonetheless, the conventional acid-based neutralization process (ABNP) for polyesters recycling faces economic and efficiency challenges due to substantial alkali consumption. To address these challenges, this study developed an electrochemical recovery and separation system (ERSS), a three-chamber electrolyzer separated by cation exchange membranes (CEM), with an ion separation module (ISM) situated between the anode and cathode of a water electrolysis system. Through water electrolysis, the system can efficiently recover excess KOH from polyester hydrolysates by leveraging directed ion migration under an electric field. Experimentally, the system achieves outstanding performance in real PET hydrolysates, with a KOH Faraday efficiency of 96.4%, yielding 88.4% for ethylene glycol (EG) and 89.3% for p-phthalic acid (PTA). The system operates stably and continuously for 100 h, processing ≈6 liters of hydrolysate. Additionally, it has exceptional KOH recovery across multiple polyester hydrolysates. A techno-economic analysis (TEA) shows that compared to the traditional ABNP, the ERSS significantly reduces chemical input costs in the hydrolysis unit, achieving savings of up to 62.5%. This study provides an efficient and cost-effective solution for the alkaline hydrolysis recycling of waste polyesters, effectively mitigating the economic drawbacks of excessive KOH usage.
Mira Shin,Minjin Kim,Giyoung Shin,Sung Bae Park,Hyeonyeol Jeon,Dongyeop X. Oh,Jun Mo Koo,Wangyun Won,Jeyoung Park
The efficient recycling of poly(ethylene terephthalate) and poly(butylene terephthalate), the most extensively produced plastics, is essential for reducing global carbon emissions and the current dependence on fossil resources. However, the chemical recycling of polyesters primarily involves polymer-to-monomer and monomer-to-polymer processes, resulting in significant greenhouse gas emissions owing to significant electricity and fuel consumption. Herein, this research reports a simple and efficient one-pot polymer-to-polymer upcycling process that directly converts these two polyester wastes into biodegradable thermoplastic poly(ether ester)s using poly(tetramethylene ether) glycol (PTMG). The synthesized series of poly((ET- co -BT)- mb -PTMG) (PEBTG) exhibit a maximum tensile strength of 68 MPa, with 85% weight loss after 20 weeks in composted soil. Techno-economic analysis and life cycle assessment indicate that PEBTG is more cost-competitive and environmentally beneficial than currently existing plastics derived from fossil fuels, such as polypropylene and polybutylene adipate terephthalate. Once de-risked, the proposed upcycling strategy for polymer waste can be extended to expedite the development of a sustainable plastic economy.
危险品化学品经营许可证（带存储）