MICROCHIMICA ACTA
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2019
·Vol. 186
·期 8
·1-8
·
IF 5.479
Qin Zucheng,Jiang Yanxiao,Piao Huilan,Tao Shuo,Sun Ying,Wang Xinghua,Ma Pinyi,Song Daqian
Halloysite nanotubes (HNTs) were functionalized with gold nanoparticles. The morphology and structures of this composite were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, and surface area and pore-size analyses. The material was employed, in conjunction with a syringe pump and an organic filter head, to the enrichment of five triazines (atrazine, desmetryn, prometorn, tebumeton, ametryn) in spiked rice samples. Several parameters that may affect the extraction efficiencies, including type and volume of extraction solvent, amount of sorbent, times of ultrasonic extraction and adsorption, volume and flow rate of elution solvent, were optimized. Following elution with acetonitrile, the herbicides were quantified by using HPLC. Under the optimum conditions, the LODs of the method, when applied to spiked rice samples, are the range from 0.06 to 1.32 ng g −1 (LODs = 3SD/k). The relative intra-day and inter-day recoveries ranged from 80.6 to 106.5% and 80.4–107.3%, respectively, and relative standard deviations ranged from 0.8 to 8.7% and 3.6–9.6%, respectively.
Packed hybrids of gold nanoparticles and halloysite nanotubes (Au/HNTs) were prepared and applied to the dispersive solid-phase extraction by packed sorbent of five triazine herbicides from rice.
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CHEMOSPHERE
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2019
·
IF 5.108
Yulin Yang,Ying Liu,Xian Fang,Wei Miao,Xiaoyan Chen,Jing Sun,Bing-Jie Ni,Shun Mao
Transition metal and nanocarbon-based composites with high activity and stability draw great attention in electro-Fenton system for organic pollutants removal . In this study, HKUST-1-derived Cu@C nanoparticles embedded within three-dimensional reduced graphene oxide (rGO) network (denoted as 3DG/Cu@C) is synthesized through a simple strategy. The prepared catalyst shows ordered 3D porous carbon structure and Cu@C NPs are uniformly dispersed in the matrix. The 3DG/Cu@C is used as heterogeneous electro-Fenton (hetero-EF) catalyst and shows outstanding performance in various persistent organic pollutants removal. High concentration Rhodamine B (RhB) (40 mg L −1 ) can achieve a complete decolorization within 150 min with 25 mg L −1 3DG/Cu@C catalyst, which is one of the lowest catalyst dosages in hetero-EF for RhB removal. More importantly, the 3DG/Cu@C achieves high RhB mineralization efficiency of 81.5% and exhibits high catalytic performance in a wide pH window from 3 to 9. The 3DG/Cu@C also remains high efficiency after five successive reaction cycles. The working mechanism study shows that RhB is mainly oxidized by • OH and O 2 •- radicals through hetero-EF and anodic oxidation processes. The high stability and outstanding performance of 3DG/Cu@C provide new insights in organic pollutants removal by hetero-EF process with transition metal and nanocarbon-based catalysts.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Ying Liu,Wei Miao,Xian Fang,Yulin Tang,Deli Wu,Shun Mao
The development of metal-free catalysts with high activity and stability for persulfate activation draws increasing attention due to their promising performance and environmental benignity. Herein, hierarchically porous nitrogen (N)-doped carbon (N C) with merits of highly-dispersed nitrogen, large surface area and controllable structure is synthesized. The as-prepared N C exhibits outstanding performance for peroxydisulfate activation in the degradation of diverse organic pollutants, as well as a wide working pH range of 3–10. Impressively, an annealing strategy can regulate C O and graphitic N contents in N C and their quantitative correlations with the reaction rate constants reveal that the C O and graphitic N in N C are active sites. Furthermore, peroxydisulfate activation by N C involves with three pathways in which the contribution from radicals (SO 4 − , OH) are comparatively weak and non-radical pathways including singlet oxygen ( 1 O 2 ) and electron transfer are dominant. The contribution of 1 O 2 is diminishing with delay of reaction while the electron transfer shows the opposite trend. Besides, good recycling performance is achieved by facile re-annealing of N C. This work provides new insights into the reaction mechanism of persulfate catalysis and can guide future catalyst development in advanced oxidation process.
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CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Ying Liu,Xiaoyan Chen,Yulin Yang,Yong Feng,Deli Wu,Shun Mao
Cobalt-based nanostructures have shown a great potential for radical production by activating persulfate (PS). Here, we report a facile strategy to synthesize nitrogen-doped porous Co@C nanoboxes (Co@NC) by pyrolysis of zeolitic imidazolate frameworks (ZIF-67), followed by partially etching away the metallic cobalt. With a nitrogen-enriched hollow porous carbon nanobox and embedded Co nanoparticles, the Co@NC shows high efficiency in PS activation for p-Chloroaniline (PCA) removal. The degradation study shows that a complete removal of high concentration PCA is done within two minutes, which is superior to most of the reported PCA removals with PS-based advanced oxidation processes (AOPs). More importantly, the Co@NC exhibits high catalytic activities in a wide range of pH from 5 to 9. The Co@NC also shows very limited Co 2+ release with a dissolution proportion of 0.28%, much lower than previously reported Co-based catalysts, and remains high efficiency after five successive reaction cycles. A heterogeneous activation mechanism though surface reaction is proposed, in which PCA firstly absorbs on the carbon nanobox surface, then being oxidized by generated radicals and non-radical species. The unique structure and outstanding performance of Co@NC catalysts present new insights in catalyst design for PS-based advanced oxidation for organic pollutants removal in waste water.
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JOURNAL OF CHROMATOGRAPHY A
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2012
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IF 4.531
Yan-Yan Fu,Cheng-Xiong Yang,Xiu-Ping Yan
Metal-organic framework MIL-100(Fe) was explored as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography. Two groups of analytes (benzene, toluene, ethylbenzene, naphthalene and 1-chloronaphthalene; aniline, acetanilide, 2-nitroaniline and 1-naphthylamine) were used to test the separation performance of MIL-100(Fe) in the reverse-phase mode, while the isomers of chloroaniline or toluidine were employed to evaluate its performance in the normal-phase mode. The MIL-100(Fe) packed column gave a baseline separation of all the tested analytes with good precision. The separation was controlled by negative enthalpy change and entropy change in the reverse-phase mode, but positive enthalpy change and entropy change in the normal-phase mode. The relative standard deviations of retention time, peak area, peak height, and half peak width for eleven replicate separations of the tested analytes were 0.2–0.7%, 0.5–3.6%, 0.6–2.3% and 0.8–1.7%, respectively. The mesoporous cages, accessible windows, excellent chemical and solvent stability, metal active sites and aromatic pore walls make MIL-100(Fe) a good candidate as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography.
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Journal of the Taiwan Institute of Chemical Engineers
·
2014
·
IF 2.637
Wan-Qian Guo,Shuang Guo,Ren-Li Yin,Yuan Yuan,Nan-Qi Ren,Ai-Jie Wang,Dong-Xu Qu
In this study, the enhancement on 4-chloronitrobenzene (4-CNB) reduction was investigated in a dual-bioelectrochemical system with the cathode seeded by enriched 4-CNB degradation inoculums. We demonstrated that the biocathode had the ability to promote 4-CNB reduction and avoid more reluctant byproducts production. At room temperature, when initial 4-CNB concentration was 20 mg/L with 0.5 V external voltage, the 4-CNB removal efficiency reached 93.7%, while in the abiotic reactor and anaerobic bioreactor reduction rate were 62.9% and 88.4%, respectively. The 4-CNB was mainly converted to 4-CAN ( para -chloroaniline). Some of the 4-CAN could be dechlorinated and form aniline (AN), which was more degradable by microorganism. The biodiversity was richer based on the result of scanning electron microscope. Results also showed that the present used reactor was feasible to simplify pollutant transformation and improve transformation efficiency compared with the single abiotic cathode and anaerobic reactor . The bioelectrochemical reactor cathode provided a promising condition for pollutants reduction.
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Polymer Chemistry
·
2015
·Vol. 7
·期 4
·860-866
·
IF 5.52
Hongyuan Wang,Rongqi Zhu,Po Yang,Yi Gu
The chain propagations of Bisphenol A-aniline benzoxazine (defined as BA-a) polymerized by thermal induction and in the presence of various catalysts or curing agents during the curing process before gelation were investigated in this paper. DSC, gel time test and GPC were used to measure the curing behavior, number-average molecular weight (n), glass transition temperature (Tg), gel time (tgel) and curing conversion (α) of different benzoxazine systems. By comparing the experimental results (n and Tg) with the models of step polymerizations and chain polymerizations proposed by Flory et al., three kinds of chain propagations of benzoxazine were observed and confirmed. The step polymerization occurred in the thermal induction or in the presence of catalyst N,N-dibenzylaniline (tAm), and then the non-living chain polymerization and the living chain polymerization occurred, respectively, when indole (Id) and other additives such as phenol (tBp), acid (HA), imidazole (IMZ) etc. were added to benzoxazine as catalysts or curing agents. Moreover, the relationship between the chain propagation and curing kinetics of benzoxazine was also established. The chain propagation of benzoxazine systems involves step polymerization, non-living chain polymerization andliving chain polymerization, the conversion of the gel point (αgel) is almost equal to, less than and greater than the value of the conversion at which the polymerization rate reaches a maximum (αmax), respectively. The results may contribute to a better understanding of the polymerization mechanism of benzoxazine and provide new approaches to effective control of the polymerization kinetics and growth crosslink structures of benzoxazine.
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JOURNAL OF HAZARDOUS MATERIALS
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2014
·
IF 4.331
Hao Jin,Chao Wang,Jiaqi Shi,Lei Chen
The individual IC 50 (the concentrations causing a 50% inhibition of bioluminescence after 15 min exposure) of cadmium ion (Cd) and nine chlorinated anilines to Photobacterium phosphoreum ( P. phosphoreum ) were determined. In order to evaluate the combined effects of the nine chlorinated anilines and Cd, the toxicities of chlorinated anilines combined with different concentrations of Cd were determined, respectively. The results showed that the number of chlorinated anilines manifesting synergy with Cd decreased with the increasing Cd concentration, and the number manifesting antagonism decreased firstly and then increased. The joint toxicity of mixtures at low Cd concentration was weaker than that of most binary mixtures when combined with Cd at medium and high concentrations as indicated by TU Total . QSAR analysis showed that the single toxicity of chlorinated anilines was related to the energy of the lowest unoccupied molecular orbital ( E LUMO ). When combined with different concentrations of Cd, the toxicity was related to the energy difference ( E HOMO − E LUMO ) with different coefficients. Van der Waals’ force or the complexation between chlorinated anilines and Cd had an impact on the toxicity of combined systems, which could account for QSAR models with different physico-chemical descriptors.
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INORGANIC CHEMISTRY
·
2017
·
IF 4.857
Dandan Wu,Yanqiao Zhang,Ming Wen,Hao Fang,Qingsheng Wu
To meet the requirement of high catalytic efficiency toward the reduction of p-nitrophenyl compounds, we designed a new one-dimensional Fe3O4/FeNi embedded-nanostructured catalyst synthesized by a one-pot controlling-growth-reduction process in a solvothermal system, in which Fe3O4 phase was implanted in the base of FeNi alloy. In the Fe3O4/FeNi catalyst system, the Fe3O4 embedded phase attracts the nitro group of p-nitrophenyl compounds by its high-density electrons, which can efficiently promote the activity of amorphous FeNi active centers for selective catalysis toward the reduction of a range of p-nitrophenyl compounds. Moreover, for the para-group in the nitrophenyl compounds, an increasing electron-donating power contributes to a higher catalytic activity, while electron-withdrawing power obtains the reverse case. Additionally, the Fe3O4/FeNi composite nanocatalyst exhibited an outstanding cycling performance over 20 times without obvious performance decay. This work opens an avenue to design more powerful non-noble metal catalysts for green chemistry.
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ELECTROPHORESIS
·
2017
·
IF 2.744
Meng Ruan,Qiqin Wang,Huihui Wu,Yuqiang Wang,Hai Han,Zhengjin Jiang
In this study, a novel functional monomer N -[1-( α -naphthyl)ethylaminocarbonyl]-D- tert -leucine-[2-(methacryloyloxy)ethyl] amide (NA-D- tert -Leu-MA) was synthesized, and then employed to prepare polymeric monoliths (240 mm × 100 μm id) functionalized with tert -leucine derivative through a single step thermo-initiated co-polymerization approach or a multi-step post-modification approach. The multi-step approach involves the post-modification of a thiol-containing monolith with NA-D- tert -Leu-MA via “thiol-ene”click reaction. The physicochemical properties of the resulting monoliths were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry and micro-liquid chromatography. Good column stability, permeability, efficiency and reproducibility were obtained for the optimized monoliths. The poly (NA-D- tert -Leu-MA- co -ethylene dimethacrylate) monolith prepared through the single step co-polymerization approach exhibited satisfactory achiral separation performance for various analytes, including phenols, aniline derivatives and intact proteins, while its enantioseparation ability is rather poor. In contrast to that, the monolith prepared through the multi-step post-modification approach showed much higher enantioselectivity for 7-nitro-2,1,3-benzoxadiazole (NBD)-derivatized amino acids. Three NBD-derivatized amino acids (theanine, proline and norleucine) could be baseline enantioseparated.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Xing Lu,Yiwen Yang,Yanbo Zeng,Lei Li,Xiaohua Wu
Rapid and efficient detecting trace amount of environmental p -nitroaniline ( p -NA) is in urgent need for security concerns and pollution supervision. In this work we report the use of molecularly imprinted polymeric ionic liquid (MIPIL) microspheres to construct recognizable surfaces for detection of p -NA through fluorescence quenching . The p -NA imprinted microspheres are synthesized by precipitation polymerization upon co-polymerization of 3-(anthracen-9-ylmethyl)-1-vinyl-1H-imidazol-3-ium chloride (Fluorescent IL monomer) with ethyleneglycol dimethacrylate (EGDMA). The electron-rich group alkenyl imidazole in IL functional monomer can dramatically improve the emission of anthracene fluorophore and the π-π stacking, electronic, and hydrogen bond between p -NA and MIPIL can efficiently enhance the selective recognition force. The as-synthesized MIPIL microspheres present spherical shape, high fluorescence emission intensity and specific recognition, which showed rapid detection rate (1 min), stable reusable property (at least 4 time recycles), wonderful selectivity over several structural analogs, wide linear range (10 nM to 10 M) with a correlation coefficient of 0.992, and excellent sensitivity (LOD, 9 nM). As synthesis and surface functionalization of MIPIL microspheres are well established, the methods reported in this work are facile, rapid and efficient for monitoring p -NA in environmental wastewater.
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Catalysts
·
2024
·Vol. 14
·期 10
·724
·
IF 3.8
Nannan Zhan,Yan Xiao,Xingkun Chen,Yuan Tan,Yunjie Ding
In this study, carbon materials with different dimensions, including the typical one-dimensional (1D) carbon nanotube (CNT), two-dimensional (2D) graphene (GF), and three-dimensional (3D) activated carbon (AC), were investigated as a support for Pt catalysts for the selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB) to 3,4-dichloroaniline (3,4-DCAN). Notably, the Pt/CNT catalyst with the lowest dimension exhibited the best conversion of 3,4-DCNB under mild reaction conditions, followed by Pt/GF. Comprehensive characterizations, including XRD, TEM, XPS, and in situ CO DRIFTS, reveal that the dimension of carbon supports plays an important role in the particle size and electronic properties of Pt species, consequently affecting the catalytic performances of Pt catalysts. According to the results, electron-deficient Pt particles with small sizes are more favorable for the hydrogenation of 3,4-DCNB to 3,4-DCAN. In addition, dynamic tests and in situ DRIFTS of 3,4-DCNB indicated that the carbonaceous supports will largely influence the adsorption and activation capacity of the Pt catalysts, so that Pt loaded on CNT and GF are superior to that on the AC. We believe this study will provide good guidance for designing efficient carbon-supported metal catalysts for selective hydrogenation.
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