FOOD CHEMISTRY
·
2024
·
IF 8.5
Shaofeng Yuan,Jian Yang,Xiaoyan Fu,Hang Yu,Yahui Guo,Yunfei Xie,Yuan Xiao,Yuliang Cheng,Weirong Yao
The effect of tannic acid (TA) binding on the thermal degradation of boscalid was studied in this work. The results revealed that TA binding has a significant impact on boscalid degradation. The degradation rate constant of bound boscalid was reduced, and its corresponding half-life was significantly prolonged compared to the free state. Four identical degradation products were detected in both states through UHPLC-Q-TOF-MS, indicating that degradation products were not affected by TA binding. Based on DFT and MS analysis, the degradation pathways of boscalid included hydroxyl substitution of chlorine atoms and cleavage of C N and C C bonds. The toxicity of B2 and B3 exceeded that of boscalid. In summary, the binding of TA and boscalid significantly affected the thermal degradation rate of boscalid while preserving the types of degradation products. This study contributed to a fundamental understanding of the degradation process of bound pesticide residues in complex food matrices.
研究领域:
食品科学
·
环境科学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2025
·
IF 9.8
Aying Wen,Kexin Chi,Yuhang Du,Shaofeng Yuan,Hang Yu,Yahui Guo,Weirong Yao
This work systematically investigated the effect of casein on the thermal transformation behavior of oxytetracycline (OTC). Fluorescence quenching and isothermal titration calorimetry experiments confirmed that OTC binds spontaneously to casein via non-covalent interactions. The -N(CH 3 ) 2 group in OTC was identified as the primary binding site. Casein-bound OTC was prepared using a combination of dialysis and ultrafiltration. During thermal treatment, the degradation of free OTC followed zero-order kinetics, whereas casein-bound OTC adhered to first-order kinetics. Seven identical thermal transformation products were identified, but the quantities of these products varied significantly depending on the existing form of OTC molecule. The binding of casein weakened the reactivity of the -N(CH 3 ) 2 group while enhancing the reactivity of degradation sites on the adjacent ring, resulting in decreased production of three lower-toxic products and increased production of four higher-toxicity products. Cytotoxicity assays revealed that heating increased the overall toxicity of OTC, particularly in its bound form.
研究领域:
食品科学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 10
·5659-5668
·
IF 3.809
Wang Guozhen,Meng Yan,Zhou Jinping,Zhang Lina
Abstract
Herein, one-step conversion of cellulose dissolved in 1.75 mol L −1 NaOH/0.074 mol L −1 ZnO aqueous solution to organic acids was realized through a hydrothermal degradation without heterogeneous catalyst. The effects of solvent, the concentrations of NaOH and ZnO, O 2 pressure, temperature and the reaction time on the yield of organic acids were investigated and discussed. The components of the degraded products were characterized with total organic carbon and high performance liquid chromatography. The results indicated that cellulose was depolymerized successfully to organic acids. Formic acid as the predominant species with 80.0% yield was obtained at the optimal conditions (150°C, 2 h, 3.0 MPa O 2 ), which was much higher than those reported in literatures. The small amount of ZnO in the solvent played an important role not only to promote the cellulose dissolution, but also to accelerate its oxidative degradation. The main features of this one-step degradation of cellulose were the green solvent, pre-dissolution of catalyst, and high selectivity. This work opened up a new avenue for the conversion of cellulose to organic acids under mild conditions. Graphical abstract The oxidative degradation of cellulose dissolved in NaOH/ZnO aqueous solution into organic acids was conducted under pressed O 2 without heterogeneous catalyst. The yield of FA which was the main product reached up to 80.0%.
研究领域:
生物化学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2020
·
IF 7.182
Xiheng Kang,Yun-Yan Wang,Shuangfei Wang,Xueping Song
One of the key issues in the development of biofuels using lignocellulosic feedstocks is to increase the yield of fermented sugar, and simultaneously decrease the generation of fermentation inhibitors. Therefore, it is essential to understand the degradation mechanism of xylan during hot-water pretreatment. We analyzed the hydrothermal degradation products of xylan and xylose under different conditions. Results showed that furfural and formic acid formed from xylose reached a maximum value of 32.56 % and 35.14 %, respectively. By increasing the initial pH of the xylan solution, the furfural concentration can be reduced effectively to 2% and the formation of formic acid was preferred under alkaline conditions. On this basis, we proposed a new hydrothermal degradation pathway of xylan in alkaline solution. The in-depth understanding of xlyan degradation during hot water pre-treatment will be beneficial for improving the efficiency of biofuel production.
研究领域:
生物能源
·
化学工程
·
植物学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2016
·
IF 3.652
Shun Zhou,Qing He,Xiaofeng Wang,Min Ning,Ying Yang,Yingbo Xu,Yaping Zhang,Peng Zou,Zhenfeng Tian,Kaibo Chen,Hua Wang,Shike She
The effects of exogenous potassium salts on the thermal degradation of flue-cured tobacco were investigated using thermogravimetric analysis (TGA), surface area/porosity measurements (SAPM), real-time fourier transform infrared (RT-FTIR), and thermogravimetric/Fourier transform infrared spectrometry (TG-FTIR), respectively. TGA analysis showed that potassium salts accelerated tobacco’s degradation at around 150–350 °C, but improved the thermal stability of char residue at high temperature range. The porous texture analysis displayed that potassium salts reduced the pore volume and surface area of tobacco pyrolysis residues. Further study using RT-FTIR illustrated that there was a positive catalysis of potassium salts with C O, O H and C O bonds at different temperature ranges, but a protective effect was given to C H bond, C C bond and aromatic moieties except for the accelerating degradation of C H by the oxidation effect of KNO 3 . The evolution comparison of their gaseous products manifested that potassium salts cut down the emission of CO 2 , H 2 O, CO, aldehydes and alkanes, but enhanced the release of carbonyl compounds, anhydrides and alcohols at around 150–350 °C. Above 350 °C, the potassium salt-containing samples exhibited a gentle escape process for both the oxygen-bearing molecules (CO 2 , H 2 O and CO) and oxygen-free species (alkanes, methane and unsaturated compounds) in comparison with their quick emission for the virgin samples.
研究领域:
烟草科学
·
热化学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2019
·
IF 6.282
Hafezeh Nabipour,Shibin Nie,Xin Wang,Lei Song,Yuan Hu
Zeolitic imidazolate framework-8 (ZIF-8) was synthesized and used as a flame retardant in polyvinyl alcohol (PVA) aerogels . The introduction of ZIF-8 increased the roughness of the cell walls due to attachment of the ZIF-8 particles. The ZIF-8 also promoted the thermal degradation of PVA, but increased the residue yield. The limiting oxygen index (LOI) increased from 19.5% for pure PVA aerogel to 24.0% for the ZIF-8/PVA hybrid aerogel. The self-extinguishing behavior of the ZIF-8/PVA hybrid aerogel was observed in the UL-94 vertical burning test, while the PVA aerogel burned out finally. The peak heat release rate (PHRR) and total heat release (THR) of the ZIF-8/PVA hybrid aerogel were 44.2% and 12.8% lower than those of pure PVA aerogel, respectively. The decomposition of ZIF-8 to zinc oxide enhanced the barrier effect of the residues, which accounted for the suppressed PHRR and THR. This study demonstrated that incorporation of ZIF-8 can result in tunable flame retardancy for fire safety application.
研究领域:
材料科学
·
防火安全
✓ 已验证
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 8
·1182
·
IF 4.329
Degang Wang,Jie Ding,Bing Wang,Yingluo Zhuang,Zhixiong Huang
In this paper, a new polyhedral oligomeric silsesquioxane containing a phenol group (POSS-Phenol) is prepared through the Michael addition reaction, which is added to the synthesis of phenolic resin as a functional monomer. Infrared spectroscopy (IR) is used to demonstrate the chemistry structure of the synthesized POSS modified phenolic resin. After introducing POSS into the resole, a comprehensive study is conducted to reveal the effects of POSS on the thermal degradation of phenolic resin. First, thermal degradation behaviors of neat phenolic resin and modified phenolic resin are carried out by thermogravimetric analysis (TGA). Then, the gas volatiles from thermal degradation are investigated by thermogravimetric mass spectrometry (TG-MS). Finally, the residues after thermal degradation are characterized by X-ray diffraction (XRD). The research indicates that POSS modified phenolic resin shows a better thermal stability than neat phenolic resin, especially at high temperatures under air atmosphere. On the one hand, the introduction of the POSS group can effectively improve the release temperature of oxygen containing volatiles. On the other hand, the POSS group forms silica at high temperatures under air, which can effectively inhibit the thermal oxidation of phenolic resin and make phenolic resin show a better high-temperature oxidation resistance.Keywords:polyhedral oligomeric silsesquioxane;phenolic resin;thermal degradation;residual char yield
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 141
·期 10
·e55051
·
IF 3
Xiaoling Da,Zhaoyi Deng,Tong Wu,Ya Cao,Ming Xiang,Feng Yang
To study the effect of molecular structure on ethylene-vinyl alcohol copolymer (EVOH) thermal stability during processing, EVOH samples with different molecular weights and comonomer distributions were prepared by solubility fractionation from two different commercial materials, and then, the structure features of samples were characterized by 1 H-NMR, viscometry, differential scanning calorimetry, and, especially, successive self-nucleation and annealing. Their thermal stabilities were further analyzed by isothermal oxygen treatment and thermogravimetry. Attenuated total internal reflectance Fourier transform infrared spectroscopy and UV were used to obverse the structural changes in samples (the formation of chromogenic groups: CO and CC ). According to the results of isothermal oxygen treatment at 200°C, at the same ethylene content, low-molecular-weight samples have worse thermal stability, which were extremely easy to yellowing and form insoluble gel. To investigate the structure differences between the low-molecular-weight samples, it was found that long vinyl alcohol segments may not worsen the thermal stability in the conditions of the same ethylene content. But samples with a uniform distribution of ethylene segments and a certain length of ethylene segments will have better thermal stability, which makes it more difficult to form carbonyl even diketene conjugation structure.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2017
·
IF 3.086
Yinzhou Hu,Weisu Huang,Maiquan Li,Mengmeng Wang,Yajing Zhao,Tao Xu,Liuquan Zhang,Baiyi Lu,Yan He
This study aimed to investigate the effect of metal ions on the degradation of phytosterols in oils. The oil was heated at 180 °C for 1 h with/without addition of Fe 3 + , Fe 2 + , Cu 2 + , Mn 2 + , Zn 2 + , Na + , Al 3 + and Mg 2 + . Variations of β-sitosterol, stigmasterol , campesterol , brassicasterol and their degradation products were confirmed by the GC–MS analysis. In general, the increase of the metal ion concentration resulted in more phytosterol degradation, and the ability of metal ions following decreasing order: Fe 3 + > Fe 2 + > Mn 2 + ≥ Cu 2 + ≥ Zn 2 + > Na + ≥ Mg 2 + > Al 3 + . Metal ions significantly induced phytosterol autoxidation on C5, C6 and C7 on Ring B of steroid nucleus at even a low concentration, and induced dehydration on the C3 hydroxyl to form dienes and trienes at high concentration. The metal ions in oils are accounted for increasing phytosterol degradation, which decreases food nutritional quality and gives rise to the formation of undesirable compounds.
研究领域:
食品科学
·
生物化学
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2023
·Vol. 30
·期 17
·10733-10748
·
IF 5.7
Zhang Jing-Fang,Tang Ren-Cheng
Reducing the flammability of kapok fiber (KF) is an important strategy to increase its applicability. In this work, the phosphorylation of KF with ammonium dihydrogen phosphate (ADP) was used to reduce its flammability, the conditions of phosphorylation reaction were studied in detail, and the chemical groups, crystalline structure, thermal stability, heat release capability, flammability and charring ability of phosphorylated KF were analyzed. KF showed significantly higher phosphorylation level than cotton, and its phosphorylation greatly depended on ADP and urea dosage, reaction temperature and time, and pH. Urea addition, pH 6, 150 ℃ and 1 h rendered high phosphorylation with acceptable whiteness. Phosphorylated KF exhibited good char-forming, low heat release and excellent flame retardant performances during thermal degradation and combustion as evidenced by thermogravimetric, microcalorimetric, vertical combustion and combustion residue morphology analyses. The residue rate of phosphorylated KF subjected to thermal degradation exceeded 50% in nitrogen, and 25% in air. This investigation demonstrates that phosphorylated KF is an intrinsically flame retardant material. Graphic abstract
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2023
·
IF 8.7
Wei Wang,Cheng Wang,Anthony Chun Yin Yuen,Ao Li,Bo Lin,Yao Yuan,Chao Ma,Yu Han,Guan Heng Yeoh
MXene has been the subject of various studies and applications in polymer composites in recent years. However, its compatibility with hydrophobic polymers has been a significant limitation. This study presents a simple way to create MXene frameworks to realise flame retardant hydrophobic polymer composites. The fabrication process is environmentally friendly and low-cost. The PVB/HPUPO/MXene composite membrane showed a 74.7% reduction in volatile intensity during thermal degradation compared to pristine PVB. The PVB/HPUPO/MXene composite membrane also demonstrated significantly improved flame retardancy compared to pure PVB. Specifically, MXene based networks and HPUPO showed synergistic effect in improving the fire safety of PVB composites. This study offers a new approach to incorporating MXene as a flame retardant into conventional phosphorus- and nitrogen-based flame retardant systems for hydrophobic polymers with great fire retardancy.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yan Jiao,Shaoqing Wang,Boyang Sun,Yu Han,Zilu Zhang,Xiuli Shen,Zhihe Li
The efficient removal and degradation of microplastics are critical for protecting aquatic ecosystems. Herein, Fe-modified magnetic biochar (MBC) was synthesized as an adsorbent for removing microplastics in water. The effects of lignin/Fe salt mass ratios, adsorbent amount, adsorption time, adsorption temperature, solution pH, and presence of coexisting anions on adsorption efficiency were investigated. The thermal degradation behaviour and recycling characteristic of microplastics was also explored. Results showed that MBC has a developed pore structure, superparamagnetic property, and abundant oxygen-containing functional groups. The removal efficiency of polystyrene microplastics using MBC-11 was 99 %, with an adsorption capacity of 68.57 mg/g, which was 25 times higher than that of unmodified lignin biochar. The kinetics of the adsorption process followed the pseudo-first kinetic model, and the equilibrium data best fitted the Freundlich model. Thermodynamic results confirmed that adsorption over MBC was a spontaneous, heat-absorbing, and entropy-increasing process. The adsorption mechanism of PS by biochar was mainly via electrostatic and hydrophobic interactions and pore throttle. The thermal-degradation products of PS were mainly hydrocarbons, including styrene, benzene, and toluene, owing to the enhanced β-scission, H-shift, and methylation reactions at MBC catalytic sites. This study provides a scientific basis for the development of control technologies for microplastics removal in water.
研究领域:
环境科学
·
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）