CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Shishu Zhu,Chao Jin,Xiaoguang Duan,Shaobin Wang,Shih-Hsin Ho
Nonradical reactions induced by nanocarbon-driven peroxydisulfate (PDS) activation recently emerge a promising strategy of groundwater remediation or wastewater treatment, whereas the involved reaction pathways remain controversial. We here investigate and differentiate the two representative nonradical mechanisms of PDS activation on graphene-like nanosheets (GNS). The template-induced GNS exhibited a high porosity of over 1200 m 2 g −1 and a few-layered turbostratic structure with graphitic microcrystals. The nonradical oxidation system (aqueous 1 O 2 and nonaqueous electron transfer) of GNS/PDS was highly-reactive, and outperformed graphene- or metal-based activators. Although singlet oxygen ( 1 O 2 ) was detected in the bulk solution, the contribution of 1 O 2 to the entire oxidation were limited (0.004–0.43% and ~6% at neutral and alkaline pH, respectively), determined by chemical probes and steady-state kinetics. Different to the reference product (benzoquinone) of phenol oxidation by photosensitive singlet oxygenation, intermediate product in GNS/PDS was benzoic acid which barely resulted from 1 O 2 oxidation. Furthermore, surface-confined electron transfer was the major oxidation pathway verified by electronic measurement. Surface adsorption rather than hydrophobic effect of organic substrates on GNS accelerated a two-electron transfer. The nonradical oxidation exhibited a dissociation constant ( p Ka)-dependent mechanism because of competitive adsorption with S 2 O 8 2− anions. The findings facilitate a thorough understanding of carbon-catalyzed persulfate activation during in situ chemical oxidation (ISCO) and provide novel insights for the selective removal of aqueous organic contaminants in a nonradical manner.
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高影响因子
CARBON
·
2020
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IF 8.821
Lijun Cao,Shuairu Zhu,Baohai Pan,Xinyan Dai,Weiwei Zhao,Yuan Liu,Weiping Xie,Yongbo Kuang,Xiaoqing Liu
The stability and durability of laser-induced graphene (LIG) patterns embedded in polymer substrates are significant for their practical application. However, most of currently reported LIG precursors are facing the dilemma of weak structural controllability, poor resistance to acid/base, or bad processability . In this work, we efficiently converted the synthesized poly (Ph-ddm) into LIG using a straightforward CO 2 laser, aiming to find a potential LIG precursor with excellent durability under harsh conditions. The graphene structure of obtained LIG was confirmed by Raman spectra , scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Results indicated that the poly (Ph-ddm)-based LIG showed a low sheet resistance of 35 Ω/sq as well as a high specific surface area of 883 m 2 /g. And due to the superior properties of poly (Ph-ddm), the LIG patterns exhibited excellent resistance to strong acid/base solutions and high adhesion on the substrate, which ensured their stable application under severe conditions. Besides, potential application of as-prepared LIG was demonstrated in well-performed supercapacitors and electrode for water splitting in an alkaline medium . Based on the results in this work, polybenzoxazine could be a promising precursor for stable and durable LIG preparation.
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高影响因子
Applied Sciences-Basel
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2020
·Vol. 10
·期 4
·1408
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IF 2.474
Yu Sun,Yuguo Sun
This work is focused on the optimization of critical process parameters for preparation of boron-containing phenolic resin (B-containing PR), including the molar ratios of formaldehyde/phenol and potassium borate/phenol, reaction time; and measurement of surface tension of B-containing PR solution and wettability between B-containing PR solution and carbon fibers. The effects of the formaldehyde/phenol and potassium borate/phenol molar ratios on the char yield of the B-containing PR was studied. The highest char yield of B-containing PR could be as high as 71% under optimal conditions (molar ratios of formaldehyde/phenol = 1.8 and potassium borate/phenol = 0.2, and reaction time = 13 h). The effect of concentration and tested temperature on the surface tension of B-containing PR solution was investigated, and the wettability between B-containing PR solution and carbon fibers was evaluated for the first time, providing useful theory and experimental data for the preparation of B-containing PR-based composites.Keywords:boron-containing phenolic resin;molar ratio;reaction time;char yield;surface tension;wettability
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高影响因子
Environmental Science-Nano
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2020
·Vol. 7
·期 7
·1899-1911
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IF 7.683
Chunyang Nie,Zhenhua Dai,Wenjie Liu,Xiaoguang Duan,Chengyin Wang,Bo Lai,Zhimin Ao,Shaobin Wang,Taicheng An
Carbon-catalyzed persulfate activation is a metal-free advanced oxidation process for abating aqueous organic micropollutants. Recently, the electron-transfer mechanism in the activation of peroxydisulfate (PDS) has attracted tremendous interest due to its unknown nonradical reaction pathways. The conventionally used atomic-scale descriptors of adsorption energy (Eads), O–O bond length (lO–O) and S–O bond length (lS–O) cannot accurately reflect the ability of the functionalities of PDS in its activation. In this work, a new descriptor, local electrophilicity index (ω), which represents the oxidative capacity of adsorbed S2O82−, was included to identify the intrinsic active sites in carbocatalysts via density functional theory calculations. To verify the reliability of the proposed criteria, the catalytic performances of a series of highly boronated and nitrogenated carbon nanotube/nanosheet composites (BCN-NT/NS) with tailored physicochemical properties were comparatively studied for activating PDS to degrade phenol. By integrating the computational and experimental results, the catalytic activity of BCN-NT/NS was determined to not only be related to the contents of heteroatom dopants (B and N), but also the positions of B and N in the co-doping configurations. This study offers reliable criteria for determining the intrinsic catalytic sites in carbocatalysts for the activation of PDS based on an electron-transfer mechanism, which assists the rational design of nanocarbons as advanced catalysts for metal-free oxidation and water remediation.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
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2020
·Vol. 55
·期 24
·10505-10521
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IF 3.553
Xiang Mei,Zhang Fen,Tong Linchang,Wang Huaqin,Ding Yalong,Zhang Wei,Wu Zeying,Zhang Zhenwei,Wei Xuejiao,Jiang Fuhua,Deng Yaoyao
An imidazolium-based ionic liquid (IL) was employed and modified by sodium lignosulfonate (LnNa) to synthesize hierarchical ETS-10 zeolite with porous structure, morphology and surface properties effectively adjusted. The template and structure-directing effects of both IL and LnNa proved to be well maintained after modification. And more importantly, the unique molecular recognition of LnNa was preserved well, while the aggressiveness of LnNa implementing through interaction with other inorganic species can be efficiently suppressed. This led to the formation of hierarchical ETS-10 zeolite with not only high crystallinity and structure integrity but also enhanced catalytic performance in aqueous-phase biomass conversion. Thus, for guaiacol hydrodeoxygenation, a notable conversion (92.8%) and cyclohexane yield (89.7%) can be acquired. This remarkable catalytic reactivity should be owing to its distinguished analogous molecular recognition pattern, promoted crystallinity, modified morphology and porous structure, and what’s more, the strengthened acid property.
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高影响因子
ENVIRONMENTAL ENGINEERING SCIENCE
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2020
·Vol. 37
·期 5
·382-392
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IF 1.681
Jingwei Feng,Lijun Pan,Binhua Cui,Yabing Sun,Aiyong Zhang,Miao Gong
To realize the rapid concentration prediction of phenolic pollutants, simultaneous prediction of phenolic pollutants in water by wavelet analysis and support vector machine (SVM) was proposed in this article. The ultraviolet-visible (UV-Vis) absorption spectra of representative phenolic compounds were determined by spectrophotometry. Spectral analysis and spectral reconstruction were carried out by wavelet analysis. Specific types of phenolic compounds were identified by SVM classification. The regression equations of UV-Vis spectra and concentration of phenolic compounds were established by SVM regression, which was used to predict the concentration of the samples. The results showed that in the mixture of two [3-Methylphenol (m-cresol) and phenol], three [2,4-Dichlorophenol (2,4-DCP), m-cresol, and phenol], and four [2,4-DCP, 2,4,6-Trichlorophenol (2,4,6-TCP), phenol, and m-cresol] phenolic compounds, the wavelet reconstruction of phenolic compounds improved with decreasing wavelet decomposition layers. After wavelet decomposition and reconstruction, the spectra of phenolic compounds were smoother and noise elimination was more obvious. In the mixtures of two, three, and four phenolic compounds, the SVM model showed better prediction results. The predicted values by SVM and the reference values showed a good linear relationship (two phenolic compounds, R2 > 0.99; three phenolic compounds, R2 > 0.99; four phenolic compounds, R2 > 0.92). This study provides a feasible method for early warning of phenolic compound pollution in drinking water sources.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
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IF 3.573
Shaoqi Yang,Guangming Cai,Xingmei Lu,Chenguang Wang,Mi Feng,Junli Xu,Qing Zhou,Jiayu Xin,Longlong Ma
Hydrodeoxygenation (HDO) of lignin-derived phenols and dimeric ethers to biofuels has great significance for advanced utilization of renewable lignocelluloses and the future biobased economy. Herein, we find that the deoxygenation process during the lignin-derived model compound HDO process could efficiently be catalyzed by low-cost protic ionic liquids under mild conditions. 2-Hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium trifluoromethanesulfonate ([BHEM]CF3SO3) shows the highest catalytic activity for the deoxygenation reaction during the lignin-derived compound HDO process with Rh/C as the hydrogenation catalyst. The conversion of phenol is 100% under 4 MPa H2 at 130 °C for 6 h, and the yield of cyclohexane is 93.3%. Furthermore, the catalytic system with [BHEM]CF3SO3 as the deoxygenation catalyst and Rh/C as the hydrogenation catalyst demonstrates efficient catalytic activity for various lignin-derived phenols and dimeric ethers with ≥99.0% conversion and >90.0% selectivity. The catalytic system is reused five times for HDO of phenol to test its stability.
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高影响因子
RSC Advances
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2020
·Vol. 10
·期 14
·8558-8567
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IF 3.119
Jindong Wang,Wenzhi Li,Huizhen Wang,Ajibola Temitope Ogunbiyi,Xiaomeng Dou,Qiaozhi Ma
To improve the utilization of lignin, much effort has been devoted to lignin depolymerization with the aim to decrease waste and enhance profitability. Here, a dual property (acid and base) catalyst, namely S2O82−–K2O/TiO2, was carefully researched. Upon loading S2O82− and K2O onto TiO2, acid and base sites emerged, and S2O82− and K2O mutually enhanced the acid and base strengths of the catalyst enormously; this indeed facilitated lignin depolymerization. Under appropriate conditions, the yields of liquid product, petroleum ether soluble (PE-soluble) product and total monomer products were 83.76%, 50.4% and 28.96%, respectively. The constituents of the PE-soluble fraction, which are mainly monomers and dimers, can be used as liquid fuels or additives. In addition, after the catalyst was modified by Ni, better results were obtained. Surprisingly, it was found that the Ni enhanced not only the hydrogenation capacity but also the acidity. The highest high heating value (HHV) of the liquid product (33.6 MJ kg−1) was obtained, and the yield of PE-soluble product increased from 50.4 to 56.4%. The product can be utilized as a fuel additive or be converted to bio-fuel. This catalysis system has significant potential in the conversion of lignin to bio-fuel.
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PubMed
高影响因子
FUEL
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2020
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IF 5.578
Xiaohua Zhang,Weikun Jiang,Hao Ma,Shubin Wu
This study investigated the relationship between the formation of oligomers and monophenols and lignin structure during pyrolysis regarding two technical lignins from alkali lignin (AL) and corn cob hydrolysis residue lignin (CHRL). The results showed that the molecular weight distribution and inter-unit linkages varied substantially between AL and CHRL, resulting in profound differences in the content of monophenols and oligomers and their distributions in pyrolysis oil (PO). Thereinto, CHRL-PO containing higher monomers content (20.48%) and lower oligomers content (14.31%) relative to AL-PO (5.02%, 22.4%). This was attributed to the higher proportion of guaiacyl (G) units existed in AL, which tended to form oligomers and char. Additionally, the formation pathways of main monophenols from two POs were also different. In light of these findings, the thermal cracking behavior of lignin was closely bound up with its structural features. On one hand, the formation pathways of lignin-derived dimers and tetramers in PO originated from the breaking of a large amount of β-O-4, α-O-4 and C β -C γ bonds during pyrolysis process. Meanwhile, the interconversion relationship between oligomers and monophenols was also existed. Polycyclic aromatic hydrocarbon (PAH) derivatives, on the other hand, were formed by the continuous growth of smaller free radicals because of the evolutionary components (such as phenols, syringols) could form oxygen-related free radicals during the secondary reaction process. Overall, this work provided the research basis and theoretical guidance for balancing the production of oligomers and monophenols through the selection of specific lignin feedstock.
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高影响因子
Food Analytical Methods
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2020
·Vol. 13
·期 10
·1842-1851
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IF 2.667
Qu Fei,Sun Yang,Guo Shuxian,Yan Hang,You Jinmao
2,4-Dichlorophenoxyacetic acid (2,4-D) is a typical chlorinated aromatic herbicide which is widely used because of its low cost. Herein, a new fluorescent assay for 2,4-D is developed based on covalent organic frameworks (COFs) and MnO 2 nanosheets. The fluorescence of COFs is quenched effectively by MnO 2 nanosheets. Ascorbic acid 2-phosphate (AAP) is hydrolyzed by alkaline phosphatase (ALP) to produce ascorbic acid (AA), which reduces MnO 2 nanosheets into Mn 2+ , so the quenched fluorescence recovers. Additionally, 2,4-D can inhibit the catalytic activity of ALP. Therefore, the addition of 2,4-D quenches the fluorescence of COF-MnO 2 system again. Under the optimum conditions, this assay displays a wide linear range of 2,4-D from 1 to 150,000 ng/mL with a limit of detection of 0.36 ng/mL. Then, this method is successfully used to measure 2,4-D in rice, millet, and cucumber samples with satisfactory recoveries. Compared with other probes for 2,4-D detection, both of COFs and MnO 2 nanosheets are stable, cost-effective, and easily prepared. The sensitivity and linear range of 2,4-D in this strategy are superior to most reported works. This is the first time that a novel sensing platform using fluorescent COFs and MnO 2 nanosheets is developed for 2,4-D.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Zhiping Yan,Wenchao Wang,Lili Du,Jixin Zhu,David Lee Phillips,Jingsan Xu
Heterojunctions of CdS quantum dots (QDs)/TiO 2 nanotube arrays (NTAs) were synthesized via a simple vapor transport approach. The 0D/1D QDs/NTAs electrodes exhibited 5-fold improvement efficiency for photocatalytic dye degradation and hydrogen evolution compared to pure TiO 2 NTAs in a photoelectrochemistry cell, which was attributed to the faster transportation and retarded recombination of electron-hole pairs in the 0D/1D heterostructures. Femtosecond transient absorption offers deep insights into the dynamics of the charge carriers, showing that surface-trapped electrons were generated within 1.2 ps. The lifetimes for recombination of electrons at shallow trap sites with holes and deep trapped electrons with holes are prolonged to 73.2 ps and 622.6 ps, respectively. The reduced charge transfer resistance is verified by electrochemical impedance spectroscopy. Mott-Schottky plots indicated downward shifts for both the conduction band and valence band in the heterostructure. Finally, a Z-scheme photoreactive mechanism is proposed to explain the enhanced catalytic activities.
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高影响因子
Frontiers in Chemistry
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2020
·
IF 3.693
Li Kai,Wang Bo,Bolatibieke Dana,Nan Dong-hong,Lu Qiang
A new method was proposed for polygeneration of phenol and supercapacitor electrode material from pyrolysis of biomass impregnated with ammonium dihydrogen phosphate (NH4H2PO4). The pyrolysis experiments were executed to demonstrate the product distributions under different NH4H2PO4-to-poplar (PA-to-PL) ratios and pyrolysis temperatures in a lab-scale device. The results revealed that the phenol yield attained its optimal value of 4.57 wt% with a satisfactory selectivity of 20.09% at 500°C under PA-to-PL ratio of 0.6. The pyrolytic solid product obtained at this condition was then subjected to high temperature activation directly without additional activators to prepare N and P co-doped activated carbon (NPAC) as supercapacitor. The physicochemical analysis of NPAC showed that the N and P contents in NPAC reached 3.75 and 3.65 wt%, respectively. The electrochemical experiments executed in a three-electrode system indicated that the NPAC exhibited promising electrochemical performance with a satisfactory capacitance of 181.3 F g−1 at 1 A g−1.
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PubMed
高影响因子
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