SEPARATION AND PURIFICATION TECHNOLOGY
·
2018
·
IF 3.927
Xiaozeng Miao,Huiwang Dai,Jianxin Chen,Jianxi Zhu
An enhanced method of hydroxyl radical generation was studied to lead a better understanding of the catalytic mechanism of α-FeOOH in UV-Fenton system. The catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption isotherms and scanning electron microscope. The Orange II degradation and hydroxyl radical concentration under different conditions were studied in detail. The results showed that the hydroxyl radical was mainly oxidizing species for Orange II degradation. And the hydroxyl radical generation included both homogeneous and heterogeneous UV-Fenton processes. In heterogeneous UV-Fenton system, the additional oxalate could increase the ratio of homogeneous UV-Fenton process for hydroxyl radical generation. In oxalate enhanced system, the peak value of hydroxyl radical concentration would increase to 11.314 μmol/L which was nearly twice as it in heterogeneous UV-Fenton system (5.978 μmol/L). The k values of Orange II discoloration and mineralization increased to 0.386 min −1 and 0.044 min −1 , which were 1.169 and 0.692 times as that in heterogeneous UV-Fenton system (0.178 min −1 and 0.026 min −1 ). After treatment, the total iron ions concentration decreased to 2.357 μmol/L in oxalate enhanced system. The results indicated that additional oxalate was a promising enhanced method for hydroxyl radical generation in heterogeneous UV-Fenton system with α-FeOOH as catalyst.
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DOI
高影响因子
Food & Function
·
2019
·Vol. 10
·期 5
·2881-2887
·
IF 3.241
Qiuyue Lv,Yushan Lin,Zhexu Tan,Baoping Jiang,Lijia Xu,Haiqin Ren,William Chi-shing Tai,Chi-on Chan,Chi-sing Lee,Zhengbing Gu,Daniel K. W. Mok,Sibao Chen
Three dihydrochalcone-derived polyphenols, huperolides A–C (1–3), along with thirteen known compounds (4–16) were isolated from the leaves of Malus hupehensis, the well-known tea crab apple in China. Their chemical structures were elucidated by extensive spectroscopic analysis including NMR (HSQC, HMBC, 1H–1H COSY and ROESY), HRMS and CD spectra. Huperolide A is a polyphenol with a new type of carbon skeleton, while huperolides B and C are a couple of atropisomers, which were isolated from natural sources for the first time. The antihyperglycemic effects of the isolated compounds were evaluated based on assaying their inhibitory activities against α-glucosidase. As a result, phlorizin (4), 3-hydroxyphloridzin (5), 3-O-coumaroylquinic acid (12) and β-hydroxypropiovanillone (15) showed significant concentration-dependent inhibitory effects on α-glucosidase. Therefore, those compounds might be responsible for the antihyperglycemic effect of this herb, and are the most promising compounds to lead discovery of drugs against diabetes.
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DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Qingting Zhang,Andreas Goldbach,Na Ta,Wenjie Shen
Hexagonal molybdates ( h-MoO 3 ) include abundant Mo vacancies that are charge-compensated by cations residing within one-dimensional channels. Hence, they present an intriguing structural motif for Mo catalysis which has been hardly explored for selective oxidation of olefins. We discovered that NH 4 + and Ag + -exchanged h-MoO 3 display surprisingly varied behavior during propylene oxidation. Acrolein and acrylonitrile are the main partial oxidation products with the latter forming due to NH 4 + consumption. The catalytic activity more than doubles upon introduction of Ag + which also enhances selectivity for the main products up to ∼60 %. Unexpectedly, the hexagonal frameworks transform into orthorhombic α-MoO 3 40−60 °C below their reported stability limits already. In addition, Ag 2 Mo 4 O 13 and Ag nanoparticles segregate in case of Ag + -containing h-MoO 3 frameworks. The resulting Ag/Ag 2 Mo 4 O 13 /α-MoO 3 composites catalyze propylene conversion into acrolein with even higher selectivity (∼80 %). Detailed analyses indicate that Ag 2 Mo 4 O 13 drives formation of this oxygenate over these composites.
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高影响因子
SCIENCE AND ENGINEERING OF COMPOSITE MATERIALS
·
2021
·Vol. 28
·期 1
·528-539
·
IF 1.295
Su Xiaofeng,Yu Yitao,Li Bing,Wang Jing,Lu Chuan,Zong Jianping,Li Jinhui,Wang Feng
In order to prepare polyurethane–polysiloxane block copolymers, α,ω-hydroxyalkyl polysiloxanes with methacrylate side chain and α,ω-bis(2-methyl-3-hydroxypropyl)polymethyl(2-methyl-methylpropanoate) siloxanes, were synthesized and characterized in this study. The syntheses process included hydroxyl protection, hydrosilylation, deprotection, and ring-opening equilibrium reactions. The intermediates and target products were characterized by Fourier transform infrared spectroscopy and 1 H nuclear magnetic resonance methods. The characterization results showed that each step was successfully carried out in all the cases. Then the waterborne polyurethane–polysiloxane block copolymers were prepared via step-growth polymerization. The properties of the block copolymer films were characterized by thermal gravimetric analysis, differential scanning calorimetry, and dynamic thermomechanical analysis methods in detail. The experimental results showed that the block introduction of hydroxyalkyl polysiloxane could reduce the water absorption of waterborne polyurethane from 62 to 11%, and significantly improve the water resistance of polyurethane. With the introduction of polysiloxane, the tensile strength decreased and the elongation at break increased. At the same time, with the increase of the polysiloxane content, the glass transition temperature of the soft segment decreased to −56.4°C and the thermal decomposition temperature increased to 300°C. The results revealed that the introduction of polysiloxane could effectively improve the comprehensive performance of polyurethane–polysiloxane block copolymer films.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2021
·Vol. 46
·期 3
·2737-2747
·
IF 5.164
Yueheng Fan,Aiming Wu,Xiaohui Yan,Shuiyun Shen,Zhang Junliang
Summary Both the activity and structure of a cathode, when it is used in non-aqueous Li-O 2 batteries, play a prominent role in the aspects of durability and capacity. In this work, α-MnO 2 /prGO hybrid nanocomposites with a three-dimensional (3D) porous structure are proposed to act as the cathode to improve the battery performance. Highly active α-MnO 2 /prGO nanocomposites with different mass ratios are synthesized through a two-step template method and a subsequent annealing process. It is found that the optimal 50% α-MnO 2 /prGO cathode exhibits outstanding discharge capacity of 13 294 mAh g −1 under the condition of 100 mA g −1 . Meanwhile, with the limited capacity and currency density of 1000 and 100 mA g −1 , respectively, the battery maintains excellent durability for 239 cycles. Significantly, it is clear that the excellent electrochemical performance of the nanocomposites is strongly associated with the synergistic effect of their distinct porous architecture and the ORR/OER catalytic activity.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Changwei Bai,Gang Yang,Shirong Zhang,Shihuai Deng,Yanzong Zhang,Chao Chen,Jingsong He,Min Xu,Lulu Long
A novel electrocatalytic anode (ECA)/α-MnO 2 /peroxymonosulfate (PMS) synergistic system was developed and evaluated for the removal of combined tetracycline (TC) and hexavalent chromium (Cr(VI)) pollution from waste waters. The factors affecting the efficiency of the removal of the combined pollutants, such as the synthesis time of the electrode, the amounts of raw materials, the PMS dose, the voltage, the initial pH and the coexisting ions were investigated. The breakdown products of PMS in the ECA/α-MnO 2 /PMS system improved the conductivity of the solution and the electrical current promoted the conversion of the valence state of Mn ions, resulting in a synergistic effect between the ECA and PMS activation processes, which improved the efficiency of removal of TC. The cathode chamber was fully utilized to simultaneously reduce Cr(VI). Synergistic effects occur in the ECA/α-MnO 2 /PMS system in appropriate ranges of the voltage or PMS dose, although the efficiency of the removal of TC depends mainly on the electrical current in the system. Both hydroxyl (•OH) and sulfate (SO 4 •− ) radicals played important parts in the degradation of TC. The main degradation products of TC were identified and degradation pathways proposed. The synergistic effects between the ECA process and a Fenton-like process was studied, providing a new approach for the study of electro-Fenton technology and the removal of combinations of TC and Cr(VI) from waste waters.
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高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2020
·
IF 1.701
YangLing Wang,Chen Wu,XiaoYa Zhou,MoRan Zhang,Yi Chen,ShaoPing Nie,MingYong Xie
Gallic acid or its alkyl ester was added in combination with α-tocopherol in the oil-in-water (O/W) emulsion to investigate their interaction in emulsions. Results showed that all the tested gallate esters (propyl, octyl and dodecyl gallate) showed synergistic antioxidant activities with α-tocopherol, and propyl gallate with the shortest alkyl chain length possessed the highest synergistic ability. The interaction efficiency was consistent with the order of their apparent static quenching constants obtained from fluorescence quenching studies. This suggested that the antioxidant synergy could be due to their molecular interactions. With further confirmation by antioxidant decomposition studies, the mechanism for such antioxidant synergy in O/W emulsions was proposed to begin with the initial quick oxidation of α-tocopherol into α-tocopherol quinine, resulting in its oriented exposure to the interfacial membrane of O/W emulsion and, subsequently, being reduced by propyl gallate esters in the interfacial layer to regenerate α-tocopherol.
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高影响因子
ACS Omega
·
2019
·
IF 2.584
Ning Shi,Qiying Liu,Rongmei Ju,Xiong He,Yulan Zhang,Shiyun Tang,Longlong Ma
Catalytic hydrothermal conversion of carbohydrates could provide a series of versatile valuable platform chemicals, but the formation of solid humins greatly decreased the efficiency of the process. Herein, by studying the hydrothermal degradation behavior and analyzing the degradation paths of kinds of model compounds including carbohydrates, furan compounds, cyclic ketone derivatives, and some simple short carbon-chain oxy-organics, we demonstrate that α-carbonyl aldehydes and α-carbonyl acids are the key primary precursors for humin formation during the hydrothermal conversion process. Then, we analyzed the hydrothermal degradation paths of two simple α-carbonyl aldehydes including glyoxal and pyruvaldehyde and found that the α-carbonyl aldehydes could undergo aldol condensation followed by acetal cyclization and dehydration to form solid humins rich of furan ring structure or undergo Cannizaro route (hydration followed by 1,2-hydride shift) to form corresponding α-hydroxy acids. On the basis of the hydrothermal behavior of the α-carbonyl aldehydes, we mapped the hydrothermal degradation routes of carbohydrates (glucose, fructose, and xylose) and illuminated the formation details of α-carbonyl aldehydes, α-hydroxy acids, γ-lactones, furfural derivatives, and humins. Finally, we deduced the typical structure fragments of humins from three α-carbonyl aldehydes of pyruvaldehyde, 2,5-dioxo-6-hydroxy-hexanal, and 3-deoxyglucosone, all of which could be formed during the hydrothermal degradation of hexose.
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高影响因子
Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 33
·13705-13712
·
IF 0
Zewen Fu,Tengfei Jiang,Lijing Zhang,Bingkun Liu,Dejun Wang,Lingling Wang,Tengfeng Xie
In this paper, we present the fabrication of Ti-doped α-Fe2O3 and surface treatment with Al3+ for application as a photoanode in photoelectrochemical water splitting. The Ti-doped α-Fe2O3 with Al3+ treatment shows a 100 mV cathodic shift of the onset potential and a notable improvement of the photocurrent density. The samples were characterized by SEM, TEM, HRTEM, XRD, Raman, UV-vis and XPS to obtain the information after surface treatment. Based on electrochemistry and photoelectrochemistry techniques, it appears that surface treatment with Al3+ passivates the surface states and decreases the accumulation of charge at the surface of Ti–Fe2O3. The results show that Ti-doped Fe2O3 with Al3+ surface treatment can be used as an efficient photoanode for photoelectrochemical water splitting.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2017
·
IF 4.233
Dandan Fu,Zhuoqun He,Shanshan Su,Bin Xu,Yuling Liu,Yaping Zhao
Arsenic pollution has caused worldwide attention due to its mandatory toxicity. Chemical structures of the adsorbent and arsenic species greatly influence the arsenic adsorption efficiency. The goethite impregnated graphene oxide (GO)-carbon nanotubes (CNTs) aerogel (α-FeOOH@GCA) was prepared via a facile self-assembly method of GO-CNTs induced by in-situ Fe 2+ reduction. α-FeOOH@GCA showed excellent adsorption capacities of 56.43, 24.43 and 102.11 mg g −1 for As(V), DMA and p -ASA comparing with that of 25.71, 8.03 and 14.52 mg g −1 of pristine α-FeOOH, respectively. The incorporation of GO-CNTs not only hinders the aggregation of GO-CNTs but also inhibits the growth of α-FeOOH nanoparticles greatly facilitating the diffusion and adsorption capacity of arsenic species. α-FeOOH@GCA shows wide favorable application pH for arsenic species adsorption, high adsorption kinetics and excellent reusability. The phosphate and silicate anions compete with the arsenic species for active adsorption sites due to the similar anionic structure. Based on FTIR spectra, arsenic species were proven to form inner sphere complex on the surface of α-FeOOH@GCA through different ligand exchanging mechanism greatly dependent on the molecular structures of arsenic species. The results show that α-FeOOH@GCA could be used as promising adsorbent for arsenic purification in water system.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Wenting Zhou,Yongkang Huang,Xiaofeng Gao,Zixuan Ma,Ziyu Song,Lili Lin,Ding Ma,Siyu Yao
Pt/α-MoC catalysts, synthesized by supporting platinum on α-phase molybdenum carbide (α-MoC), have emerged as promising candidates for the low-temperature water–gas shift reaction (WGSR) due to their high catalytic activity. However, their performance is often limited by insufficient density of active Pt–Mo interfacial sites and inadequate stability under reaction conditions. In this study, a ternary Pt/α-MoC/MFI catalyst was constructed by incorporating MFI-type zeolites with varying Si/Al ratios as a support component. Comprehensive characterization revealed that modulating the Si/Al ratio of the zeolite support alters the carburization process, with silica-rich supports promoting the formation of a more optimal molybdenum carbide structure and effectively suppressing carbon deposition during reaction. In addition, the use of high-silica supports increased the number of active Pt–Mo interfacial sites and enhanced key steps such as water dissociation and –OH group conversion. Consequently, the Pt/α-MoC/S-1 catalyst─synthesized using purely siliceous S-1 zeolite as the support─exhibited the highest intrinsic activity of 7.4 molCO/molPt/s at 523 K, outperforming all other zeolite-supported Pt/α-MoC catalysts as well as the bulk Pt/α-MoC catalyst.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Chaoqun Huang,Xuerui Jin,Yeyi Kan,Can Cui,Longchen Wei,Huayi Liu,Dawen Niu,Yunzi Luo
Nonnatural amino acids hold the promise of enhancing enzyme activity and bolstering the efficacy of drugs. Enzymatic synthesis emerges as a valuable adjunct to traditional synthetic methodologies, providing an alternative pathway for the generation of nonnatural amino acids. This study introduces a one-pot enzymatic strategy for the synthesis of aryl and heteroaryl γ-hydroxy-α-amino acids. The process involved the utilization of a newly identified aldolase from Streptomyces to catalyze the formation of C–C bond from the cost-effective fluorinated pyridine aldehyde substrate, and an α-transaminase sourced from Saccharomyces cerevisiae to transfer an amino group. After optimization, a 94% conversion efficiency was achieved, along with a product diastereoselectivity ratio of up to 13:87. Furthermore, the one-pot reaction system demonstrated efficacy across a broad spectrum of substrates, including fluorinated pyridines, quinolines, azabiphenyls, thiazoles, and phenyl derivatives. This study significantly broadened the scope of nonnatural amino acids containing heteroaromatic rings and diversified the array of enzymes accessible for the production of functionally diverse bioactive fluorinated compounds.
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高影响因子
危险品化学品经营许可证（带存储）