JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Weitao Ou,Han Wang,Yingdan Ye,Huaiyuan Zhao,Yibin Zhang,Zhaoyin Hou
Chemical upcycling of waste polyethylene terephthalate (PET) to value-added products can reduce the emission of CO 2 , microplastics and toxic chemicals. In this work, mesoporous H-type Zeolite Socony Mobil-5 (HZSM-5) supported Ru catalyst (Ru/ m -HZSM-5) was synthesized and tested in the hydrogenation of PET degraded chemicals (bis(2-hydroxyethyl) terephthalate , dimethyl terephthalate, diethyl terephthalate, and terephthalic acid). Characterizations disclosed that Ru/ m -HZSM-5 catalyst possesses mesopores (a dominant channel of 5.32 nm), enlarged specific surface area (404 m 2 ·g −1 ), and Ru NPs dispersed highly (40.6 %) compared to that of Ru/HZSM-5. And also, it was found that Ru/ m -HZSM-5 was capable for the hydrogenation of benzene rings in these PET degraded chemicals with large sizes (1.09–1.82 nm). In particular, the conversion of BHET and the selectivity of BHCD over Ru/ m -HZSM-5 reached 95.5 % and 95.6 % at 120 °C within 2 h. And Ru/ m -HZSM-5 could be recycled at least five times without obvious loss of activity and selectivity.
研究领域:
化学工程
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环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
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2024
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IF 7.1
Anamika Kushwaha,Lalit Goswami,Beom Soo Kim
In this study, we established an innovative and integrated chemical/biological methodology for the complete poly(ethylene terephthalate) (PET) degradation and biopolyol production using cerium–iron oxide nanoparticles (CeFeNPs). Initially, three nanoparticles, i.e., CeNPs, FeNPs, and CeFeNPs, were synthesized and evaluated for PET glycolysis. CeFeNPs demonstrated the best catalytic performance for PET depolymerization to bis(2-hydroxyethyl) terephthalate (BHET) and were further recovered from the PET depolymerized slurry to be reutilized again. BHET was further biodegraded using the hydrocarbonoclastic bacterium Pseudomonas aeruginosa PR3 under the batch modes using a shake flask and a stirred tank bioreactor. To elucidate the fate of BHET biodegradation under aerobic conditions, identification of various BHET degraded metabolites was carried out using liquid chromatography–mass spectrometry analysis. The strain could produce an extracellular diol synthase enzyme, which transforms oleic acid into the biopolyol, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). CeFeNPs were further supplemented to enhance DOD production via whole cell and cell-free approaches.
研究领域:
环境科学
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生物化学
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材料科学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
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IF 4.2
Maoxin Li,Wenyan Chen,Wenxing Chen,Shichang Chen
Poly(ethylene terephthalate) (PET) is glycolyzed to obtain bis(hydroxyethyl) terephthalate (BHET), and repolymerization produces new PET material, making this a sustainable recycling process. However, most studies have reported common metal-based catalysts, which typically have harsh synthetic conditions and are prone to negative environmental impacts. In this study, 1,8-diazabicyclo[5.4.0]undec-7-ene-based deep eutectic solvents (DBU-based DESs) effectively degraded PET to obtain BHET due to their high activity, low price, and accessible production properties. Under the optimized reaction conditions (DES 3.2 wt %, PET/ethylene glycol (EG) 1:3, 180 °C, 70 min), PET bottle flakes were completely degraded, and the yield of BHET achieved 83%. In addition, a possible degradation mechanism was postulated based on experimental data and calculations using density functional theory (DFT). The formation of hydrogen bonds between EG and DES and between PET and DES can promote glycolysis of PET, which in turn could facilitate the attack of hydroxyl oxygen in ethylene glycol (EG) on carbonyl carbon in PET.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2025
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IF 7.3
Chenjing Qu,Xiaolong Han,Haiyun Wang,Ruidong Wang,Yifei Zhang,Weiwei Sun,Ziqian Shi,Yuting Wang,Penggang Yin
The widespread use of poly(ethylene terephthalate) (PET) has led to severe environmental pollution and significant resource depletion. The depolymerization of waste PET into bis(2-hydroxyethyl) terephthalate (BHET) offers considerable potential for chemical recycling. Although conventional glycolysis faces challenges such as low degradation efficiency and high energy requirements, an efficient catalytic method was developed herein to convert postconsumer PET into BHET under milder conditions. The incorporation of the cosolvent dimethyl sulfoxide (DMSO) into the reaction system reduced the degradation temperature to 150 °C, significantly lower than the temperature observed without cosolvents, which exceeded 190 °C. Under optimized conditions, the combination of a metal catalyst and the organic nitrogen heterocycle 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) enabled complete depolymerization of PET within 90 min, yielding BHET at 80.11%. In addition, the recrystallized product was repolymerized into PET, enabling closed-loop resource recycling. Life cycle assessment (LCA) indicates that this closed-loop approach is not only technically feasible but also environmentally beneficial, reducing energy consumption by approximately 64.54% and greenhouse gas emissions by 37.32%. This strategy offers a practical low-carbon solution for the sustainable recycling of waste PET.
研究领域:
高分子化学
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催化
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绿色化学
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废弃物回收
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Sustainability
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2025
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IF 4.9
ZIXIAN JIA,JIE ZHANG,LIN GAO,LIJIAO QIN,HAOCHENG SUN,JIAXING CHEN,Jian-Zhong Yin
The chemical recycling of polyethylene terephthalate (PET) via glycolysis is a promising route for recovering the monomer bis(2-hydroxyethyl) terephthalate (BHET), which can be used for virgin-grade PET production. However, the influence of water—an inevitable impurity and potential byproduct—on this process is complex and not fully elucidated. This study systematically investigates the effect of water content (0–22.2 vol%) on PET glycolysis using selected heterogeneous catalysts (ZnO, Mn₂O₃) and homogeneous catalysts (zinc acetate (ZnAc₂), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)). Product distribution and reaction kinetics were quantified by HPLC and in-situ IR spectroscopy, respectively.The heterogeneous catalysts (ZnO, Mn₂O₃) and homogeneous ZnAc₂ maintained high PET conversion (>95%) even at elevated water concentrations. Nevertheless, the BHET yield and selectivity for these systems decreased significantly due to a competing hydrolytic side reaction, promoted by water, which yields terephthalic acid (TPA). Notably, ZnAc₂ exhibited a more rapid decline in BHET selectivity compared to ZnO. Conversely, the organic base catalysts TBD and DBU experienced complete deactivation in the presence of water, resulting in a drastic reduction in both PET conversion and BHET yield, with DBU showing greater susceptibility. In-situ IR experiments corroborated that the deactivation mechanism for TBD involves protonation by water. These results emphasize that water's influence is a function of the catalyst's chemical nature, modulating product selectivity for metal-based systems while causing the deactivation of organic bases. Understanding these divergent effects is critical for the optimization of industrial PET glycolysis and the rational design of water-tolerant catalytic systems.
研究领域:
高分子化学
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催化化学
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化学回收
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反应工程
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环境化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2021
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IF 5.909
Junjie Huang,Dongxia Yan,Huixian Dong,Fei Li,Xingmei Lu,Jiayu Xin
Chemical recycling is a promising way to achieve the closed-loop recycling for polyethylene terephthalate (PET). During this process, the post-consumer PET is depolymerized into bis(2-hydroxyethyl) terephthalate (BHET) through glycolysis and BHET can be polymerized again to produce recycled PET (rPET). However, since the applications of rPET is greatly limited to the color, recycling of PET fibers is challenged by the residual of colored impurities. In this study, a modified recrystallization process using ethyl acetate (EA) as the solvent was employed for the removal of colored impurities from the BHET. The process showed a decoloring rate of over 97.5% for the model colored impurities, performing better than the reported physical adsorption processes . Since almost no disperse dye was precipitated during the nucleation and crystal growth process due to the high solubility in EA, only a small amount of colored impurities adsorbed on the surface of crystals, leading to an excellent decolorization performance and post-consumer EA could be easily recycled through evaporation followed by condensation. Besides the model colored BHET, raw BHET obtained from the depolymerization of dark PET fibers was also purified by this modified recrystallization. By applying a composite purification strategy combining EA-based recrystallization and activated carbon adsorption, the whiteness (L*) of BHET greatly increased from around 65 to over 95 (L*=100 for pure white) and the whiteness of rPET produced from purified BHET (L*=86.21) was greatly improved compared with that from raw BHET (L*=44.01), showing the possibility of achieving the closed-loop recycling of dark PET fibers.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMERS AND THE ENVIRONMENT
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2024
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IF 4.7
Yang Ge,Wu Hao,Huang Ke,Ma Yukun,Chen Qi,Chen Yun,Lin Shanshan,Guo Hailing,Li Zhibo
The recycling of polyethylene terephthalate (PET) waste plastics has garnered global attention as an essential area of research to address. Chemical upcycling methods, such as glycolysis, offers a visible solution by directly converting PET wastes into high-valued monomers, enabling their reintegration into the plastic life cycle. However, the recovery of metal salt catalyst and the thermal stability of organic catalyst pose challenges in PET glycolysis. Zeolites with strong Brønsted acid are widely used in the degradation of polyolefins, but in PET glycolysis, they face the problems of acid site mismatch and difficult contact with PET. In this work, nanosized FAU-type zeolite catalysts (100-FAU) were employed to carry out PET glycolysis, which were green synthesized at low temperature without organic template. In comparison to commercial FAU-type catalysts, 100-FAU exhibits enhanced Lewis acidity and basicity along with increased accessibility to active sites. The 100% degradation of PET was achieved within 1 h, resulting in a BHET yield of 64.2%. Prolonging the reaction time to 1.5 h led to an enhanced BHET yield of 72.1%. The quality of the primary product bis(2-hydroxyethyl) terephthalate (BHET) was verified through IR, DSC, and NMR characterizations. Furthermore, as a solid catalyst with high thermal stability, zeolite can be easily recovered via filtration and demonstrated stable performance over at least 5 cycles, and proved effective for glycolysis of commercially waste PET plastics. The acid–base dual-functional catalytic mechanism of Na-form FAU in PET glycolysis was proposed. Under its guidance, the promoting effect of other Na-form nanosized zeolites on PET degradation was verified.
研究领域:
材料科学
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化学工程
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环境科学
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催化
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
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2021
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IF 5.03
Zishuai Wang,Yaoqiang Wang,Shengnan Xu,Yu Jin,Zequn Tang,Gang Xiao,Haijia Su
Glycolysis of poly (ethylene terephthalate) (PET) is a promising way to recycle waste PET and produce bis-(2-hydroxyl ethyl) terephthalate (BHET), the monomer of PET. However, traditional catalysts will cause environment pollution and economic burden. In this work, based on the green and low-cost graphitic carbon nitride colloid, we developed a pseudo-homogeneous system for PET glycolysis, and poly (bisphenol A carbonate) (BPA-PC) and polylactic acid (PLA) methanolysis. Using this system, 100% conversion of PET and 80.30% yield of BHET were achieved, and the reaction time was 2-8 times shorter than that of other metal-based catalysis systems. Catalyst and ethylene glycol were reused five times directly preserving their activity. Furthermore, the degradation of real commercial plastics has also been achieved. According to FT-IR, XPS, and 1 H NMR characterization results, the nucleophilic attack ability of ethylene glycol and electrophilicity of the PET carbonyl's carbon are enhanced by the formation of hydrogen bond between ethylene glycol, PET and catalyst.
研究领域:
材料科学
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化学工程
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环境科学
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催化
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高分子化学
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回收技术
✓ 已验证
产品关联
DOI
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
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2021
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IF 3.978
Kun Chen,Mingqin Quan,Xiaoyan Dong,Qinghong Shi,Yan Sun
Polyethylene terephthalate is one of the most widely used synthetic plastics. The accumulation of abandoned PET has brought an environmental problem. A recently reported PET hydrolase , PETase, displays an efficient decomposition to PET. Herein, we synthesized four PETase conjugates by modifying four types of monomers onto PETase, which were hydrophobic tert-butyl methacrylate (TBMA), hydrophilic hydroxyethyl methacrylate (HEMA), positively charged 2-(dimethylamino)ethyl methacrylate (DMAEMA), and negatively charged methacrylic acid (MA). Despite the low modification with an average number of 3–5 monomers on each enzyme molecule, all the PETase conjugates exhibited improved enzyme activity , and thermal and pH stability. Particularly, the catalytic efficiency ( k cat / K m ) of TBMA-/DMAEMA-PETase toward bis-2(hydroxyethyl) terephthalate (BHET) increased 1.4 and 1.6-fold as compared with PETase. Characterizations by fluorescence and circular dichroism spectroscopy unraveled that the modification induced the structural transformations, including compact overall structure and opened substrate-binding pocket, which were in favor of the enhanced catalytic performance. Biodegradation against PET films by TBMA-/DMAEMA-PETase were 4.69 and 3.26-fold higher than PETase. The different catalytic performances of the enzyme conjugates for BHET and PET are considered due to the different interactions of the conjugates with the different substrates. The work demonstrated that the low modifications with hydrophobic and hydrophilic monomers were both effective in improving the catalytic performance toward PET degradation, especially for the hydrophobic and positively charged monomers.
研究领域:
生物技术
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环境科学
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酶学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）