Attallah Olivia A, Azeem Muhammad, Nikolaivits Efstratios, Topakas Evangelos, Fournet Margaret Brennan
Materials Research Institute, Technological University of the Shannon: Midlands Midwest, N37 HD68 Athlone, Ireland.
Pharmaceutical Chemistry Department, Faculty of Pharmacy, Heliopolis University, Cairo-Belbeis Desert Road, El Salam, Cairo 11777, Egypt.
Polymers (Basel). 2021 Dec 29;14(1):109. doi: 10.3390/polym14010109.
Effective interfacing of energy-efficient and biobased technologies presents an all-green route to achieving continuous circular production, utilization, and reproduction of plastics. Here, we show combined ultragreen chemical and biocatalytic depolymerization of polyethylene terephthalate (PET) using deep eutectic solvent (DES)-based low-energy microwave (MW) treatment followed by enzymatic hydrolysis. DESs are emerging as attractive sustainable catalysts due to their low toxicity, biodegradability, and unique biological compatibility. A green DES with triplet composition of choline chloride, glycerol, and urea was selected for PET depolymerization under MW irradiation without the use of additional depolymerization agents. Treatment conditions were studied using Box-Behnken design (BBD) with respect to MW irradiation time, MW power, and volume of DES. Under the optimized conditions of 20 mL DES volume, 260 W MW power, and 3 min MW time, a significant increase in the carbonyl index and PET percentage weight loss was observed. The combined MW-assisted DES depolymerization and enzymatic hydrolysis of the treated PET residue using LCC variant ICCG resulted in a total monomer conversion of ≈16% () in the form of terephthalic acid, mono-(2-hydroxyethyl) terephthalate, and bis-(2-hydroxyethyl) terephthalate. Such high monomer conversion in comparison to enzymatically hydrolyzed virgin PET (1.56% ()) could be attributed to the recognized depolymerization effect of the selected DES MW treatment process. Hence, MW-assisted DES technology proved itself as an efficient process for boosting the biodepolymerization of PET in an ultrafast and eco-friendly manner.
高效连接节能型和生物基技术为实现塑料的连续循环生产、利用和再生产提供了一条全绿色途径。在此，我们展示了使用基于低共熔溶剂（DES）的低能量微波（MW）处理随后进行酶水解的方法，对聚对苯二甲酸乙二酯（PET）进行超绿色化学和生物催化解聚。由于其低毒性、生物可降解性和独特的生物相容性，DES正成为有吸引力的可持续催化剂。选择了一种由氯化胆碱、甘油和尿素组成的三元绿色DES，用于在微波辐射下对PET进行解聚，无需使用额外的解聚剂。使用Box-Behnken设计（BBD）研究了微波辐射时间、微波功率和DES体积等处理条件。在20 mL DES体积、260 W微波功率和3分钟微波时间的优化条件下，观察到羰基指数和PET失重百分比显著增加。使用LCC变体ICCG对经处理的PET残渣进行微波辅助DES解聚和酶水解相结合的方法，以对苯二甲酸、单（2-羟乙基）对苯二甲酸酯和双（2-羟乙基）对苯二甲酸酯的形式实现了约16%（）的总单体转化率。与酶水解的原始PET（1.56%（））相比，如此高的单体转化率可归因于所选DES微波处理过程公认的解聚效果。因此，微波辅助DES技术证明了自身是一种以超快且环保的方式促进PET生物解聚的有效方法。
