ChemCatChem
·
2019
·Vol. 11
·期 14
·3327-3338
·
IF 4.495
Man Yuan,Hongbo Zhang,Chen Yang,Fanhao Wang,Zhengping Dong
Graphical It′s nanoreactor time : Co@ZDC@mC nanoreactor with a hierarchical mesoporous yolk-shell structure was successfully prepared by the high-temperature carbonization of a ZIF-67@polymer composite. The Co@ZDC@mC-700 exhibited superior catalytic efficiency in the catalytic reduction of nitrobenzene with N 2 H 4 ⋅H 2 O, and also showed good reusability and recyclability. Porous nanoreactors demonstrate immense potential for applications in heterogeneous catalysis due to their excellent mass-transfer performance and stability. The design of a simple, universal strategy for fabricating nanoreactor catalysts is of significance for organic transformation. In this study, a nanoreactor with a hierarchical mesoporous yolk-shell structure was successfully prepared by the high-temperature carbonization of a ZIF-67@polymer composite. The core of the resultant Co@ZDC@mC material comprised Co NPs anchored in the ZIF-67-derived carbon framework, while the shell comprised resin-polymer-derived mesoporous carbon. The as-obtained Co@ZDC@mC-700 catalyst enriched reactants, efficiently catalyzed the reaction in the core, and permitted the desorption of the product from the nanoreactor. In the catalytic reduction of nitrobenzene with N 2 H 4 ⋅H 2 O, Co@ZDC@mC-700 exhibited superior catalytic efficiency (TOF=1136.3 h −1 ). In addition, Co@ZDC@mC-700 exhibited excellent performance for the catalytic reduction of various functionalized nitroarenes, as well as good reusability and recyclability. Hence, a simple, useful approach for fabricating a metal-organic-framework-derived non-noble metal-based yolk-shell nanoreactor for effective catalytic transformation is proposed.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 7
·1-10
·
IF 5.479
Yue Yuhua,Jiang Li,Li Zhen,Yuan Jie,Shi Haizhu,Feng Shun
A glassy carbon electrode (GCE) was consecutively modified with amino groups and phosphate groups, and then loaded with Zr(IV) ions. Fourier transform infrared spectrophotometry, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy and cyclic voltammetry were used to characterize the morphologies and electrochemical properties. The sensor was used to detect p-nitrophenyl-substituted organophosphorus pesticides, with methyl-parathion (MP) as the model analyte. Under optimized conditions, the oxidation current of square wave voltammetry (typically measured at around −0.28 V vs. saturated calomel electrode) increases linearly in the 1.0 to 100 ng mL −1 MP concentration range, and the detection limit is 0.25 ng mL −1 (at a signal to noise ratio of 3). Average recoveries from (spiked) real water samples are 99.9–102.2%, with relative standard deviations of 0.3–2.6% ( n = 3) at three levels. The reliability and accuracy of the method was validated by HPLC.
Zr(IV) modified GCE is prepared via three steps. The electrode shows high specificity and selectivity towards methyl‐parathion. And the linear range is 1.0 ‐ 100.0 ng mL‐ 1 with the detection limit as low as 0.25 ng mL‐ 1 with SWV.
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高影响因子
ADVANCED SYNTHESIS & CATALYSIS
·
2019
·Vol. 361
·期 15
·3525-3531
·
IF 5.451
Jitao Wang,Xiaochun Yu,Chongyang Shi,Dajie Lin,Jun Li,Huile Jin,Xian Chen,Shun Wang
A facile fabrication of Fe and N co-doped mesoporous carbon (MC), as an efficient heterogeneous catalyst for the highly selective reduction of nitroarenes, is described. The Fe and N co-doped MC nanosheets are easily synthesized via a hydrothermal reaction between citrate acid and magnesium citrate, followed by calcination in the presence of melamine and potassium ferrocyanide. The Fe−N complex provides a unique active site for the selective reduction of 1-chloro-4-nitrobenzene, leading to the production of (E)-1,2-bis(4-chlorophenyl)diazene with a selectivity of >96%, in <40 mins. Control experiments based on non-doped, N-doped, and Fe-doped MC nanosheets demonstrate that selectivity greatly depends on the catalyst active component type, and that non-doped MC significantly contributes to the high efficiencies observed in the selective synthesis of azoxy compound intermediates. A broad range of substrates, including extra-functional groups on the nitroarenes rings, were successfully converted to the corresponding azo compounds at mild conditions with high selectivity.
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Shuangyu Xiong,Luminita Marin,Lian Duan,Xinjian Cheng
Nitroaromatic compounds, especially 2, 4, 6-trinitrophenol, have strong biological toxicity and explosive risks, so the detection of 2, 4, 6-trinitrophenol exhibit importantly practical and scientific significance. In this work, three fluorescence functionalized chitosan CNS 3 , CNS 4 and CNS 5 were prepared using chitosan as matrix. When 2, 4, 6-trinitrophenol (TNP) and/or p-nitrophenol (4-NP) was present in spot, these fluorescent chitosan sensors produced notable fluorescence quenching. It renders the chitosan sensing ability to detect TNP and 4-NP selectively and sensitively. The sensing mechanism is investigated as well. When introduced electron-rich moieties to the fluorescent chitosan, the sensitive detecting ability could be obtained. Excellent recognition ability could reach as low as 0.28 μM. The fluorescence fictionalization cause slight influence to the gel performance of chitosan.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Jin Huang,Jie Cao,Ni Tu,Huaping Dong,Jianfa Li,Jianxin Shou,Yimin Li
Nonionic and anionic surfactants often occur in anaerobic environments, but their roles in the removal of organic contaminants by Fe-bearing mineral/Fe(II) have not been determined. In this study, batch experiments were performed to investigate the effects of a nonionic surfactant (TX-100) and an anionic surfactant (SDBS) on the removal of nitrobenzene (NB) by Fe-bearing montmorillonite (FM)/Fe(II). Mössbauer spectrum and XPS were applied to analyze the edge surface bound Fe(II) and secondary minerals formed on FM. The contribution of surfactant to the enrichment of NB on FM was studied. The results showed that TX-100 and SDBS had opposite effects on the removal of NB by FM/Fe(II) at neutral pH. The presence of TX-100 improved the removal efficiency of NB from 36.4% to 70.0%, and increased the initial removal rate by 1.7 times. This enhancement effect was mainly attributed to the formation of more active edge surface bound Fe(II) that can reduce more NB to aniline. Formation of more magnetite on FM and selective enrichment of NB on the reactive surface also contributed to the removal of NB. In contrast, the presence of SDBS reduced the amount of edge surface bound Fe(II) via formation of SDBS-Fe(II) complex, which decreased the removal efficiency of NB.
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CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Amina,Xiongyuan Si,Kang Wu,Youbin Si,Balal Yousaf
In this study, a modified Fenton system using calcium peroxide (CaO 2 ) powder, as an effective source of hydrogen peroxide (H 2 O 2 ), for the degradation of sulfamethoxazole (SMX) in aqueous solution was investigated. Our results indicated that degradation of SMX in Fe(II)-EDTA catalyzed CaO 2 system was readily more efficient than in Fe(II) catalyzed CaO 2 system. The SMX degradation efficiency was found maximum at pH 6.0 and SMX degradation was suppressed as the initial solution pH was increased. Nevertheless overall removal efficiency in this system was favorable near to neutral pH. In addition, it was observed that the higher bicarbonates (HCO 3 − ) contents had a considerable scavenging ability to SMX degradation while low concentration exhibited auspicious role. The presence of chlorides (Cl − ), nitrates (NO 3 − ), sulfates (SO 4 2− ), and humic acid (HA) could improve SMX removal in this Fenton-like system. Furthermore, chemical probe and radical scavenging activity confirmed the formation of hydroxyl (HO ) and superoxide (O 2 − ) radicals, and also described that the SMX degradation was predominantly due to the HO -induced oxidative destruction. Electron paramagnetic resonance (EPR) studies for different systems, different pH values and different reaction times were carried out to determine the HO radical intensities. EPR results showed that HO intensities were higher in Fe(II)-EDTA catalyzed CaO 2 system, at pH 6.0 and at 90 s reaction time, respectively. Intermediate products of SMX were identified and possible mechanism of SMX degradation was suggested. In conclusion, this work provided comprehensive knowledge for the use of Fe(II)-EDTA catalyzed CaO 2 system for remediation of SMX contaminated sites.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Pingping Yan,Qian Sui,Shuguang Lyu,Hongyuan Hao,Horst Friedrich Schröder,Wilhelm Gebhardt
Fe(II) activated sodium percarbonate (SPC) process (SPC/Fe(II)) could efficiently remove sulfamethoxazole (SMX) in the aqueous phase, and has the potential in groundwater remediation . However, the degradation mechanisms, especially the degradation products and pathways till now have remained unclear. In the present study, intermediate products were identified using high resolution liquid chromatography coupled with ion trap and time-of-flight mass spectrometry (LCMS-IT-TOF). Nine intermediate products were identified, six of which have not yet been reported during the oxidation of SMX. The oxidation mechanisms involved hydroxyl substitution, the cleavage of sulfonamide bond, isoxazole ring opening and a rearrangement following the loss of the SO 2 -group. Based on the identified intermediate products, the degradation pathways of SMX by SPC/Fe(II) process were illustrated. Fenton's reaction after the dissolution of SPC was proposed as the main reaction mechanisms, which was checked and confirmed by radical species detection tests and radical species scavenging studies. The results showed that although both O 2 − and HO were present in SPC/Fe(II) system, HO was dominant in the system while O 2 − was seldom involved in the degradation of SMX. These findings provided useful information and supported the application of this advanced oxidation process for antibiotics elimination in the groundwater.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2018
·
IF 2.88
Jinxia Xu,Zhangjun Bai,Fanlin Zu,Fanyong Yan,Junfu Wei,Saihui Zhang,Yunmei Luo
A convenient, highly sensitive and reliable assay for 2,4,6‑trinitrophenol (TNP) and Fe (III) ion (Fe 3+ ) in the dual spectroscopic manner is developed based on novel carbon dots (CDs). The CDs with highly blue emitting fluorescent were easily prepared via the one-step potassium hydroxide-assisted reflux method from dextrin . The as-synthesized CDs exhibited the high crystalline quality, the excellent fluorescence characteristics with a high quantum yield of ~13.1%, and the narrow size distribution with an average diameter of 6.3 ± 0.5 nm. Fluorescence and frequency doubling scattering (FDS) spectra of CDs show the unique changes in the presence of TNP/Fe 3+ by different mechanism. The fluorescence of CDs decreased apparently in the presence of TNP via electron-transfer. Thus, after the experimental conditions were optimized, the linear range for detection TNP is 0–50 μM, the detection limit was 19.1 nM. With the addition of Fe 3+ , the FDS of CDs appeared to be highly sensitive with a quick response to Fe 3+ as a result of the change concentration of the scattering particle. The emission peak for FDS at 450 nm was enhanced under the excitation wavelength at 900 nm. The fluorescence response changes linearly with Fe 3+ concentration in the range of 8–40 μM, the detection limits were determined to be 44.1 nM. The applications of CDs were extended for the detection of TNP, Fe 3+ in real water samples with a high recovery. The results reported here may become the potential tools for the fast response of TNP and Fe 3+ in the analysis of environmental pollutants .
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 4
·2718-2725
·
IF 3.201
Fan Yang,Yan Cao,Zhuo Chen,Xing He,Liqiang Hou,Yongfeng Li
Boron and nitrogen co-doped graphene-like carbon (BNG) is a metal-free catalyst that has been synthesized by combining ball-milling with thermal treatment. Firstly, the edge-selectively-functionalized graphene nanoplatelets (EFGnPs) were prepared by ball milling of the pristine graphite, which can facilitate boron incorporation. BNG catalysts with a high content of boron and nitrogen can then be obtained by pyrolysis of a mixture of EFGnPs and boric acid. We found that the reduction of nitroarenes can be catalyzed using a low BNG loading and a small amount of N2H4 in ethanol to form aminoarenes in high yields. The type of boron species in the BNG catalyst has an important effect on the reduction reaction. Furthermore, the catalyst containing the most B/N shows the highest catalytic activity during the reduction of nitroarenes, indicating that the doped B/N within the BNG is a key active site in impelling this reaction. Moreover, the BNG catalyst can be used six times, and no dehalogenation phenomenon occurs during the reduction process for halogen-substituted nitroarenes in contrast to the case when conventional metal catalysts are used.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2018
·Vol. 56
·期 20
·2280-2285
·
IF 2.588
Dao-Guang Teng,Xian-Yong Wei,Zheng Yang,Zhi-Min Zong
Thermostable and fluorescent poly(phenylene methylene) (PPM) was synthesized via α-Fe 2 O 3 /attapulgite (α-Fe 2 O 3 / A )-mediated polymerization of benzyl chloride (BC) in CCl 4 in good yields. A carbocationic mechanism was proposed based on the controlling experiment. The structure and properties of PPM were characterized by Fourier transform infrared spectrometry, 1 H and 13 C nuclear magnetic resonance spectrometry, thermogravimetric analysis, elemental analysis, gel permeation chromatography, and UV–vis and fluorescence spectrometry. The results show that PPM possesses outstanding homoconjugation fluorescence and excellent thermal stability with onset decomposition temperature of ca. 420 °C. Recycled α-Fe 2 O 3 / A proved to be still highly active for BC polymerization. Moreover, the strategy features low-cost and readily accessible starting materials, simple one-pot operation, and recyclable catalyst, facilitating future applications. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56 , 2280–2285
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WATER RESEARCH
·
2018
·
IF 7.051
Tongcai Liu,Kai Yin,Chengbin Liu,Jinming Luo,John Crittenden,Weiqiu Zhang,Shenglian Luo,Qunying He,Yongxiu Deng,Hui Liu,Danyu Zhang
Oxcarbazepine (OXC) is ubiquitous in the aqueous environment. And due to its ecotoxicological effects and potential risks to human, an effective way to eliminate OXC from aqueous environment has aroused public concerns in recent years. Radical-based reactions have been shown to be an efficient way for OXC destruction, but the reactions of OXC with reactive oxygen species (ROS) and carbonate radical (CO 3 •− ) are still unclear. In this study, we focused the degradation of OXC and ROS, CO 3 •− generation mechanism, and their roles in OXC degradation via UV and UV/H 2 O 2 . The triplet state of oxcarbazepine ( 3 OXC ∗ ) was found to play an important role in OXC degradation via UV. And hydroxyl radicals ( • OH) and singlet oxygen ( 1 O 2 ) were found to be the dominant ROS in OXC degradation. Superoxide radical (O 2 •− ) did not react with OXC directly, but it may react with intermediate byproducts. Generation of CO 3 •− played a positive role on OXC degradation for both UV and UV/H 2 O 2 . In addition to • OH, 3 OXC* also contribute to CO 3 •− production. The second-order rate constants of OXC with • OH and CO 3 •− were 1.7 × 10 10 M −1 s −1 and 8.6 × 10 7 M −1 s −1 , respectively. Potential OXC degradation mechanisms by • OH were proposed and included hydroxylation, α-ketol rearrangement, and benzylic acid rearrangement. Compared with non-selective • OH, the reactions involving CO 3 •− are mainly electron transfer and hydrogen abstraction. And the acute toxicity of OXC was lower after UV/H 2 O 2 and UV/H 2 O 2 /HCO 3 − treatments, which was confirmed by luminescent bacterial assay ( Vibrio fischeri bacterium).
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Ying Lü,Jianfa Li,Yimin Li,Liping Liang,Huaping Dong,Kun Chen,Chunxia Yao,Zhanfeng Li,Jinxiang Li,Xiaohong Guan
Zero-valent iron (ZVI) is a popular reductant that has been successfully applied for remediation of groundwater contaminated with various pollutants, but it still suffers from surface passivation and pH increase in the reaction media. In this study, pyrite, a ubiquitous sulfide mineral in anaerobic environment, was adopted to enhance the reactivity of ZVI for removal of nitrobenzene. The synergetic effect between pyrite and ZVI was observed for nitrobenzene reduction, and the rate constant k obs at the initial pH (pH 0 ) 6.0 was enhanced by 8.55–23.1 folds due to the presence of pyrite with pyrite/ZVI mass ratio ranging from 1.0 to 6.0. Moreover, nitrobenzene could be removed effectively at pH 0 ranging from 5.0 to 10.0 in the presence of pyrite, while negligible removal of nitrobenzene by ZVI (0.5 g/L) alone was observed at pH 0 ≥7.0. ZVI sample recovered from the reacted ZVI/pyrite mixture was also more effective for nitrobenzene degradation than pristine ZVI. The mechanism study revealed that pyrite could suppress the pH increase in reaction media, boost the production of reactive Fe 2+ , and activate the ZVI surface through replacing partially the passive oxide film with iron sulfide (FeS). In particular, the formation of highly reactive FeS@Fe in the reaction system of ZVI/pyrite mixture was proved by XRD, Mössbauer, XANES, XPS and SEM-EDS analyses, which provides a facile way for in-situ sulfidation of ZVI and for enhancing the removal of contaminants with ZVI technology.
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