Polymers
·
2021
·Vol. 13
·期 4
·609
·
IF 4.329
Guifang Yang,Na Lin,Yuan Li,Xiaoxia Ye,Yifan Liu,Yuancai Lv,Chunxiang Lin,Minghua Liu
A novel cellulose–styrene copolymer adsorbent (cellulose-St) was prepared using free radical polymerization. Successful polymerization was confirmed through Fourier Transform Infrared Spectroscopy (FTIR), Carbon 13 Solid Nuclear Magnetic Resonance (13C NMR) Spectroscopy, Scanning Electron Microscopy (SEM), etc. Cellulose-St possessed good hydrophobicity, and the best water contact angle of cellulose-St samples could reach 146°. It had the ability of adsorption for nitrobenzene (NB), and the adsorption process could be well described by the pseudo-second-order (R2> 0.99) and three-stage intraparticle diffusion (R2> 0.99) kinetic models. Furthermore, the dynamic adsorption experiments revealed that cellulose-St had the potential for continuous separation of NB in water, and the breakthrough point for the initial NB concentration of 10 mg/L reached 1.275 L/g. Moreover, cellulose-St exhibited excellent environmental adaptability that it could maintain its hydrophobicity and adsorption ability for NB in strong acids, strong alkalis, or organic solvents. The used cellulose-St could be reused after washing with ethanol and keep almost constant adsorption capacity after ten cycles.Keywords:cellulose;styrene;hydrophobicity;nitrobenzene;polymerization
研究领域:
环境科学
·
材料科学
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
He Han,Anfeng Zhang,Limin Ren,Xiaowa Nie,Min Liu,Yi Liu,Chuan Shi,Hong Yang,Chunshan Song,Xinwen Guo
Shape-selective alkylation of toluene with methanol is one of the most attractive promising synthetic routes to para -xylene. To date, modified ZSM-5 zeolites are considered to be one of the best candidate catalysts for this reaction. Although the para -selectivity could be tuned to approaching 100% by modification of the zeolite and optimization of reaction conditions, at present, there is still a lack of effective means to inhibit the rapid deactivation of the catalysts due to coke formation. In this work, a coke-resistant (Pt + Ni)/ZSM-5 zeolite with excellent stability for shape-selective alkylation of toluene with methanol to para -xylene is developed. The pore structure and acid properties of the zeolite are effectively tuned to ensure high para -selectivity. Meanwhile, the co-existence of Pt and Ni species in this catalyst plays the critical role in inhibiting coke formation, as the two species concurrently impede the formation of olefins, the main coking precursors, via two distinctive mechanisms.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Jiasheng Wang,Qingrong Wang,Mengdi Zhao,Ming Bao
Toluene gas-phase oxidation is a green, chlorine-free production process for benzaldehyde but its conversion efficiency is still unsatisfying due to the lack of highly efficient catalyst. Here the selective oxidation of toluene to benzaldehyde over V-Ag-Ce/TiO 2 under an air atmosphere was investigated. The catalyst was prepared by impregnation and characterized by scanning electron microscope (SEM), N 2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), H 2 temperature programmed reduction (H 2 -TPR), O 2 temperature programmed desorption (O 2 -TPD), and NH 3 temperature programmed desorption (NH 3 -TPD). The amount of oxygen vacancy and acid of the catalyst can be tuned through adjusting the V:Ag:Ce ratio. Over the optimum catalyst (V:Ag:Ce = 4:2:1, molar ratio), 92% benzaldehyde selectivity with a 27% toluene conversion can be obtained at 550 °C. Medium amounts of oxygen vacancy (0.43) and acidity (0.10 mmol/g) are found to be conducive to the conversion of toluene to benzaldehyde. This study has important theoretical guiding significance for improving conversion efficiency from toluene to benzaldehyde by gas-phase aerobic oxidation.
研究领域:
催化化学
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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
高影响因子
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
·
2023
·
IF 7
Bo Zhou,Wei Wang,Zhendong Zhou,Xiangdong Liu,Yongping Chen
The hollow polymer spheres preparation technique of micro-encapsulation requires quantative and precise understandings of the complex evaporation, gelation and solidification processes of the polymer solution. This study focused on the mass transfer during the evaporation-gelation process of a PS-benzene solution inside a Stefan tube. Liquid level reductions of polymer solutions were accurately measured using an image-recognition method with 50 μ m accuracy. An evaporation model was developed to successfully predict the variation of liquid level, concentration and mass transfer flux, considering solution activity and density as lumped parameters that depend on concentration. This carefully validated evaporation model is expected to be invaluable for the analysis and design of polymer solution evaporation, accommodating various geometries and boundary conditions. Despite the observation of complex processes such as precipitation of polymer molecules and solution-gel phase separation, we characterized and explained them using the effective concentration-density relation. The study showed that reaching a mass fraction of benzene of 0.6 is a significant event in the evaporation process, indicating the end of gelation and the beginning of solidification.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2020
·
IF 6.306
Yong Han,Xie He,Weixia Yang,Xueli Luo,Ying Yu,Wenzhi Tang,Tianli Yue,Zhonghong Li
A ratiometric fluorescent sensor was facilely fabricated using innate fluorescence of carbendazim (MBC) and fluorescent UiO-67 to sensitively and selectively detect MBC in food matrixes. The innate fluorescence of MBC provided a signal at 311 nm (F 311 ), and the fluorescent UiO-67 at 408 nm (F 408 ) could recognize MBC through π-π stacking inducing fluorescent quenching relied on photoelectron transfer (PET). The ratio (F 311 /F 408 ) of the fluorescence enhancement of MBC and the quenching of UiO-67 linearly responded to the MBC concentrations of 0–47.6 μmol/L with a low limit of detection (LOD) of 3.0 × 10 −3 μmol/L. The reverse response signals of the sensor enhanced the sensitivity toward MBC and presented remarkable anti-interference capability in complex matrices. The as-prepared sensor was applied to detect MBC residues in apple, cucumber and cabbage, obtaining satisfactory accuracy and precision with the recovery of 90.82–103.45% and RSDs of lower than 3.03%.
研究领域:
食品科学
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Synthetic Biology
·
2022
·
IF 5.249
Jiawei Li,Mario Roque Huanca Nina,Xiaoyan Zhang,Yunpeng Bai
Poly(ethylene terephthalate) (PET) and phthalate esters (PAEs) are used extensively as plastics and plasticizers. Enzymatic degradation of PET and PAEs has drawn great attention in recent years; however, evolution of PET- and PAE-degrading enzymes is still a big challenge, partly because of the lack of an effective screening method to detect phthalic acid (PA) and terephthalic acid (TPA), which are the main hydrolysis products of PAEs and PET. Here, by directed evolution of a promiscuous transcription factor, XylS from Pseudomonas putida, we created two novel variants, XylS-K38R-L224Q and XylS-W88C-L224Q, that are able to bind PA and TPA and activate the downstream expression of a fluorescent reporter protein. Based on these elements, whole-cell biosensors were constructed, which enabled the fluorimetric detection of as little as 10 μM PA or TPA. A PAE hydrolase, GoEst15, was preliminarily engineered using this new biosensor, yielding a mutant GoEst15-V3 whose activity toward dibutyl phthalate (DBP) and p-nitrophenyl butyrate was enhanced 2.0- and 2.5-fold, respectively. It was shown that 96.5% DBP (5 mM) was degraded by GoEst15-V3 in 60 min, while the wild-type enzyme degraded only 55% DBP. This study provides an effective screening tool for directed evolution of PAE-/PET-degrading enzymes.
研究领域:
生物技术
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环境工程
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生物化学
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DOI
PubMed
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 34
·e202403054
·
IF 1.9
Yifei Wang,Ze Wang,Pengfei Qin,Songgeng Li
Graphical Reactivities of 2-methylphenol, 2-methoxyphenol, 4-methylphenol and 4-methoxyphenol with formaldehyde, and the thermal stabilities of the resoles are investigated. The reactivity of ortho phenol is found higher than that of para phenol. The resole of para phenol has a higher thermal stability than that of ortho phenol. The resole of methylphenol generally has a higher thermal stability than that of methoxyphenol. Bio-oil formaldehyde resole (BFR) can be used as adhesive in plywood industry. However, the BFR has a lower thermal stability, and the reason is still unclear. Herein, the reactivities of four representative phenolic compounds in bio-oil, including two ortho phenols (2-methylphenol, 2-methoxyphenol) and two para phenols (4-methylphenol and 4-methoxyphenol), as well as the thermal stabilities of the prepared resoles are investigated. The results show that the reactivity of an ortho phenol is higher than that of a para phenol. The resole prepared from a para phenol has a higher thermal stability than that of an ortho phenol. The resole of an ortho phenol decomposes even when heated at the low temperature of 100 °C. The resole of a methylphenol generally has a higher thermal stability than that of a methoxyphenol. Based on the results, the reason for the low reactivity of bio-oil and the low thermal stability of BFR are speculated.
研究领域:
化学
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材料科学
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生物能源
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产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 408
·期 19
·5247-5259
·
IF 3.125
Pan Ziyu,Peng Jingdong,Zang Xu,Lei Gang,He Yan,Liu Di
A novel, highly selective, and sensitive resonance light scattering (RLS) detection approach coupled with high performance liquid chromatography (HPLC) was researched and developed for the synchronous analysis of three kinds of benzimidazole anthelmintics, including mebendazole (MBZ), albendazole (ABZ), and fenbendazole (FBZ) for the first time. In the pH range of 3.5–3.7 Britton-Robinson buffer medium, three kinds of anthelmintics, which were separated by HPLC, reacted with eosin Y (EY) to form 1:1 ion-association complexes, resulting in significantly enhanced RLS signals and the maximum peak located at 335 nm. The enhanced RLS intensity was in proportion to the MBZ, ABZ, and FBZ concentration in the range 0.2–25, 0.2–23, and 0.15–20 μg/mL, respectively. The limit of detection was in the range of 0.064–0.16 μg/mL. In addition, human urine was determined to validate the proposed method by spiked samples and real urine samples. Satisfactory results were obtained by HPLC-RLS method.
The diagram mechanism of generating resonance between emitted light and scattered light
研究领域:
分析化学
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药物分析
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Zhengwen Wei,Xiang-fei Lü,Wei Wang,Giuseppe Mele,Zhen-Yi Jiang
Phenanthrene (PTH) and 9-phenanthrol (9-PTH) exhibited severe health threats and ecological hazards, for this reason, exploring a high-efficient removing strategy for PTH and 9-PTH could be considered of great urgency. Herein the 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer (magnetic BIPH-PHEN) was successfully fabricated via Schiff base polycondensation reaction and the subsequently one-pot embedded method. The mutual aromatic nucleus of BIPH-PHEN polymer and PTH/9-PTH could form π–π interaction, thus improving the capture ability, the embedded Fe 3 O 4 nanoparticles provided the possibility for rapid separation. The physical and chemical properties of the magnetic BIPH-PHEN were systematically characterized. The removal rate of magnetic BIPH-PHEN towards PTH and 9-PTH was 85.65 % and 98.52 %, respectively (PTH or 9-PTH: 8 mg/L; Adsorbent: 0.2 g/L). The DFT calculations including energy calculations and electrostatic potential distribution analyzed the different bonding modes and proposed the most possible bonding modes in the adsorbent/adsorbate system. Moreover, the LUMO and HOMO orbits combined with energy gaps analysis proved the existence and specific types of the π–π interaction. The monolayer adsorption occurred on the homogeneous magnetic BIPH-PHEN surface, simultaneously the chemisorption was dominant. This work not only proposed new sights on assembling magnetic Schiff base polymer for removing polycyclic aromatic hydrocarbons, but also provided a deeper understanding of intramolecular interactions.
研究领域:
环境科学
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材料科学
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理论化学
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产品关联
DOI
PubMed
高影响因子
Polymer Chemistry
·
2020
·Vol. 11
·期 11
·1937-1946
·
IF 5.342
Yang Jiao,Guofei Chen,Nafeesa Mushtaq,Haijun Zhou,Xiaoqi Chen,Yantao Li,Xingzhong Fang
Two isomeric diamine monomers, 2-(3-aminophenyl)benzo[d]oxazol-5-amine (2a) and 2-(3-aminophenyl)benzo[d]oxazol-6-amine (2b), were designed and synthesized. The corresponding novel series of poly(benzoxazole imide)s (PBOPIs) were prepared with commercial tetracarboxylic dianhydrides via thermal imidization. These series of PBOPIs showed great Tgs ranging from 285 to 363 °C, excellent thermal stability when performed at 5% weight loss temperatures (Td5%s) of 510–564 °C in N2 and good mechanical properties (tensile strengths of 103–126 MPa, tensile moduli of 2.9–3.7 GPa and elongations at break of 3.0–6.5%). Furthermore, controlled molecular weight (Mw) polymers PI-3a-PA and PI-3b-PA derived from 4,4′-oxydiphthalic anhydride (ODPA) with 2a and 2b demonstrated good melt processability with minimum complex viscosities of 2258 and 3444 Pa·s at 420 °C and low melt viscosity ratios of 1.29 and 1.93 at 400 °C, respectively. The PI-b series showed higher Tg & Td5% and lower transparency compared with the PI-a series due to the isomeric effect.
研究领域:
高分子科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2021
·Vol. 14
·期 1
·234
·
IF 3.004
Yu Ji,Qiang Yao,Weihong Cao,Yueying Zhao
To probe the possibility of thiophenolate as an origin of dibenzothiophenes (DBTs) and establish the detailed chemical transformations from thiophenolate to DBTs, the thermal degradation of thiophenolate has been carried out at various temperatures. The characterizations of both gaseous products and solid residues indicate that DBTs together with benzene, diphenyl sulfide, and diphenyl disulfide are the major degradation products. The presence of benzene supports that the thermal degradation of thiophenolate begins with the homolysis of Ar‒H bonds. The subsequent hydroarylation followed by the elimination and cyclization reactions facilely generates DBTs. The transformation of thiophenolate to DBTs is chemically simple and highly geochemically feasible. It readily unifies the chemical pathways involved in the generation of DBTs from thiophenolate and that of dibenzofurans from phenolate in nature.Keywords:thiophenolate;dibenzothiophene;phenyldibenzothiophene;homolysis;hydroarylation;aromatic sulfur heterocyclics
研究领域:
化学
·
地质化学
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产品关联
DOI
高影响因子
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
·
2023
·Vol. 103
·期 6
·2824-2837
·
IF 4.1
Yiting Wen,Yujia Zhang,Xiaoli Zhang,Linjun Wang,Qiuxia Pan,Qiuhan Bai,Du Zhu,Weiming Chai
BACKGROUND Tyrosinase is the key enzyme involved in enzymatic browning of plant-derived foods. Inhibition of tyrosinase activity contributes to the control of food browning. Due to safety regulations or other issues, most identified tyrosinase inhibitors are not suitable for practical use. Therefore, it is necessary to search for novel tyrosinase inhibitors. In this study, the anti-tyrosinase activity and mechanism of albendazole and 2-(2-aminophenyl)-1 H -benzimidazole (2-2-A-1HB) were investigated through ultraviolet–visible absorption spectroscopy, fluorescence spectra, molecular docking, and molecular dynamic (MD) simulation. The anti-browning effect of albendazole on fresh-cut apples was then elucidated. RESULTS Albendazole and 2-2-A-1HB were both efficient tyrosinase inhibitors with IC 50 of 51 ± 1.5 and 128 ± 1.3 μmol L −1 , respectively. Albendazole suppressed tyrosinase non-competitively and formed tyrosinase–albendazole complex statically. Hydrogen bond and hydrophobic interaction were major driving forces in stabilizing the tyrosinase–albendazole complex. While 2-2-A-1HB inhibited the enzyme competitively and quenched its intrinsic fluorescence through a static mechanism, it generated strong binding affinity with tyrosinase through hydrophobic interaction. MD simulations further validated that albendazole/2-2-A-1HB could form stable complexes with tyrosinase and loosened its basic framework structure, leading to a change in secondary structure and conformation. In addition, albendazole could delay the browning of fresh-cut apples by inhibiting the activity of polyphenol oxidase, peroxidase and phenylalanine ammonia-lyase, and reducing the oxidation of phenolic compounds. CONCLUSION This research might provide a deep view of tyrosinase inhibition by benzimidazole derivatives and a theoretical basis for developing albendazole as a potential fresh-keeping agent. © 2023 Society of Chemical Industry.
研究领域:
食品科学
·
生物化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）