INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2015
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IF 2.858
Zhan-Chao Wu,Zhao-Zhan Wang,Jie Liu,Jin-Hua Yin,Shao-Ping Kuang
A new porous magnetic chitosan modified by melamine (MA-CS/Fe 3 O 4 ) was synthesized. The compositions and surface topographies were characterized by infrared (IR) spectroscopy, X-ray diffraction (XRD) analysis, thermogravimetric (TG) analysis and scanning electron microscope (SEM), respectively. The results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation ( R > 0.999). The adsorption isotherm was well fitted by the Langmuir equation ( R > 0.999), and the values of separation factors were in the range of 0–1.0. The maximum adsorption capacity for Cu(II) was 2.58 mmol g −1 at the optimal experimental conditions, which were pH = 5.5, t = 25 min, C 0 = 5.0 mmol L −1 . The rate-controlling step was supposed to be chemical adsorption rather than mass transport. The adsorbent still exhibited high adsorption capacity after five regeneration cycles. The adsorption mechanism was due to coordination between Cu(II) and N atoms.
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PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
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2014
·
IF 3.674
Xiuquan Jia,Jiping Ma,Min Wang,Zhongtian Du,Fang Lu,Feng Wang,Jie Xu
The promoted effect of Cu(NO 3 ) 2 on aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) catalyzed by VOSO 4 in acetonitrile was intensively investigated. It was revealed that Cu(NO 3 ) 2 facilitated the activation of VOSO 4 to generate active V 5+ species via the generation of NO x gas. The high DFF selectivity is ascribed to Cu 2+ cation which can effectively prohibit oxidative C C bond cleavage reaction of HMF and prevent radical reaction of DFF to humins. In addition, the polarity of solvent plays a great role on high selectivity of DFF.
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APPLIED CATALYSIS A-GENERAL
·
2017
·
IF 4.339
Xinlei Wang,Kui Ma,Lihong Guo,Ye Tian,Qingpeng Cheng,Xueqin Bai,Jingjing Huang,Tong Ding,Xingang Li
Herein, we reduced the ZnO-modified copper phyllosilicate to synthesize a series of Cu/ZnO/SiO 2 catalysts ( x CuZn/SiO 2 ) which were mixed with γ-Al 2 O 3 for dimethyl ether steam reforming (DME SR). The structure and the formation of copper phyllosilicate were systematically characterized by nitrogen adsorption, XRD and IR. The novel synthetic route led to the remarkably high dispersion of copper species and adjustable Cu 0 /Cu + ratio on the catalyst surface, resulting in the superior catalytic performance for DME SR. The amount of Cu 0 and Cu + sites on the catalyst surface was dramatically affected by ZnO loading, and the turnover frequency results indicated that the 4CuZn/SiO 2 catalyst (Cu/Zn = 4) with the Cu 0 /Cu + ratio of 1 showed the highest catalytic performance. The XPS, H 2 -TPR and TEM results revealed the existence of strong interaction between Cu species and ZnO on the reduced 4CuZn/SiO 2 catalyst, which suppressed the reverse water-gas reaction and prevented the sintering of copper.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2016
·Vol. 18
·期 5
·1-9
·
IF 2.101
Liu Fenfen,He Juan,Zeng Mulang,Hao Juan,Guo Qiaohui,Song Yonghai,Wang Li
Abstract In this work, a facile strategy to synthesize Cu–hemin metal-organic frameworks (MOFs) with peroxidase-like activity was reported. The prepared Cu–hemin MOFs were characterized by various techniques such as scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, UV–visible absorbance spectra, and so on. The results showed that the prepared Cu–hemin MOFs looked like a ball-flower with an average diameter of 10 μm and provided a large specific surface area. The Cu–hemin MOFs possessing peroxidase-like activity could be used to catalyze the peroxidase substrate of 3,3,5,5-tetramethylbenzidine in the presence of H 2 O 2 , which was employed to detect H 2 O 2 quantitatively with the linear range from 1.0 μM to 1.0 mM and the detection limit was 0.42 μM. Furthermore, with the additional help of glucose oxidase, a sensitive and selective method to detect glucose was developed by using the Cu–hemin MOFs as catalyst and the linear range was from 10.0 μM to 3.0 mM and the detection limit was 6.9 μM. This work informs researchers of the advantages of MOFs for preparing biomimetic catalysts and extends the functionality of MOFs for biosensor application. Graphical Abstract
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Journal of CO2 Utilization
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2017
·
IF 4.292
Chen Zhang,Haiyan Yang,Peng Gao,He Zhu,Liangshu Zhong,Hui Wang,Wei Wei,Yuhan Sun
A series of Cu/ZnO/Al 2 O 3 catalysts with the total weight percentage of Cu and ZnO from 9.94 wt.% to 44.5 wt.% have been prepared by ammonia deposition −precipitation method and tested for methanol synthesis from CO 2 hydrogenation. A Cu/Zn/Al layered double hydroxides (LDHs) precursor can be formed in situ on the surface of microspherical Al 2 O 3 which acts as both support and sole source of Al 3+ cations. With increase of total Cu and ZnO loading, the dispersion of copper and reducibility of CuO decline continuously, while the exposed copper surface area increases gradually. In addition, the formation of LDHs results in a stronger both basicity and acid strength on the catalyst surface. It is found that the CO 2 conversion increases linearly with increase of the Cu and ZnO loading. The methanol selectivity for the catalyst with low total metal loading (9.94 wt.%) is much lower than those for other catalysts, though it increases with increasing loading, which can be mainly assigned to the much smaller Cu particle size (<5 nm) and the higher ratio of isolated CuO phase. Moreover, the Cu/ZnO/Al 2 O 3 catalyst with relatively high total metal loading (44.50 wt.%) still exhibits a considerable stable catalytic performance due to the formation of LDH structure.
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KOREAN JOURNAL OF CHEMICAL ENGINEERING
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2017
·Vol. 34
·期 8
·2331-2341
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IF 2.007
Meng Yue,Xia Shengjie,Pan Guoxiang,Xue Jilong,Jiang Junhui,Ni Zheming
Copper(II) Schiff-base Complexes (Salen-Cu(II)) intercalated zinc-chromium layered double hydroxides (ZnSBCuCr-LDHs) were successfully prepared via coprecipitation. Then, a novel photocatalytic material Zn-Cu-Cr composite oxides (ZnSBCuCr-MO) was prepared after calcination at 500 °C with ZnSBCuCr-LDHs as precursor. The structure and properties of the materials were thoroughly characterized by powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the materials were investigated by photodegradation of a cationic dye Rhodamin B (RhB), which was hard to adsorb by LDHs. The effects of the photocatalyst dosage, the initial pH and temperature of RhB solution on the photocatalytic efficiency were discussed. The results showed that ZnSBCuCr-MO displayed higher photocatalytic activity for RhB than calcined ZnCr-LDHs (ZnCr-MO) and calcined ZnCuCr-LDHs (ZnCuCr-MO). Meanwhile, ZnSBCuCr-MO exhibited better stability and reusability. In addition, the possible photocatalytic mechanism and degradation pathway for RhB were studied through density functional theory (DFT) calculation of the RhB molecule, UV-vis absorption variation and LC-MS analyses of the RhB solution.
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Waste and Biomass Valorization
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2017
·Vol. 10
·期 5
·1141-1150
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IF 1.337
Fang Chengjiang,Liu Yanxiu,Wu Weibo,Li Hu,Wang Zhongwei,Zhao Wenfeng,Yang Tingting,Yang Song
Liquid-phase catalytic hydrogenation of furfural, followed by hydration to levulinic acid has been considered as one of efficient approaches for upgrading pentose sugars. However, a two-step process is generally employed, which involves the separation and purification of the key intermediate furfuryl alcohol from the reaction mixture. To simplify this catalytic process with improved efficiency, Cu-doped niobium phosphate ( x Cu/NbP; x = 0.1–5.0 wt%, denoted as Cu loading) catalysts with different Cu loadings were prepared by impregnation and reduction, which could catalyze furfural conversion to levulinic acid through a one pot single-step process. The as-prepared x Cu/NbP catalysts were characterized by H 2 -TPR, XRD, NH 3 -TPD, XPS, the pore size and pore volume and pyridine-adsorption FT-IR. In this study, the effect of Cu loading, formic acid amount, support type, reaction temperature/time and catalyst reusability on the reaction were investigated. It was found that 1.5 wt% Cu/NbP loading exhibited predominant catalytic activity in the cascade conversion of furfural, producing levulinic acid with a high yield of up to 67.0 mmol% using ten equivalent of formic acid at 160 °C for 3 h. Moreover, the possible mechanism was further elucidated. Also, the catalyst could be easily separated from the mixture, and reused with no remarkable loss of reactivity.
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RSC Advances
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2016
·Vol. 6
·期 99
·96997-97003
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IF 3.289
Xiang Ma,Haidi Liu,Weiman Li,Shengpan Peng,Yunfa Chen
A copper-based metal organic framework (MOF-199) with controllable size and shape was synthesized and used to remove gaseous methyl mercaptan (CH3SH). Characterizations of the synthesized MOF-199 samples before and after desulfurization were carried out by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) to observe the adsorption mechanism of CH3SH on MOF-199. The adsorption performance of the synthesized MOF-199 materials and commercialized activated carbon (AC) and Cu loaded AC were evaluated by breakthrough experiments. All three synthesized MOF-199 materials show better performance than commercialized AC. The morphology and texture of MOF-199 materials have great influence on the performance of the adsorption process. The MOF-199 material synthesized by a hydrothermal method exhibited the highest sulfur compound capacity among the synthesized MOF-199 materials (74.7 mg of CH3SH/1 g MOF-199). The color change of MOF-199 during the CH3SH capturing process, indicated a strong interaction between the unsaturated copper sites and –SH group which finally formed CuS and gave rise to obvious damage to the MOF structure.
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RSC Advances
·
2016
·Vol. 6
·期 81
·78136-78150
·
IF 3.289
Li Lv,Jing Zhang,Shaojun Yuan,Liqiang Huang,Shengwei Tang,Bin Liang,Simo O. Pehkonen
To enhance the adsorption capacity of crosslinked chitosan (CCS) microspheres towards Cu(II) ions, well-defined poly(glycidyl methacrylate) (PGMA) brushes were grafted onto the surfaces of CCS microspheres via surface-initiated atom transfer radical polymerization (ATRP) for subsequent conjugation of polyethylenimine (PEI). The resultant PEI-grafted CCS (defined as CCS-g-PGMA-c-PEI) microsphere was used as an effective adsorbent to uptake Cu(II) ions from aqueous solution. Success in each functionalization step was ascertained by ATR-FTIR, XPS, SEM and water contact angle measurements. Batch adsorption experiments were performed to determine adsorption kinetics, adsorption isotherms and thermodynamics of Cu(II) ions on the CCS-g-PGMA-c-PEI microspheres. The adsorption equilibrium of Cu(II) ions on the microspheres was found to be rapidly established within 60 min at an optimal solution pH of 5.0, and the adsorption kinetics was well represented by the pseudo-second-order model, together with a significant effect of mass transfer on the Cu(II) adsorption rate. The Langmuir-fitted maximum adsorption capacity was about 3.58 mmol g−1 (229 mg g−1), and the calculated thermodynamic parameters demonstrated an endothermic and spontaneous adsorption process of Cu(II) ions. The PEI-grafted CCS microspheres also exhibited good regenerability and stability for recycle applications. The postulated adsorption mechanism was proposed to account for the adsorption process of Cu(II) ions on the CCS-g-PGMA-c-PEI microspheres.
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Li Wang,Han Yang,Juan He,Yayun Zhang,Jie Yu,Yonghai Song
Herein, a Cu-hemin metal-organic-frameworks (MOFs)/chitosan (CS)-reduced graphene oxide (CS-rGO) nanocomposite with unique peroxidase-like bioactivity and good electrical conductivity was prepared for electrochemical H 2 O 2 sensing for the first time. The prepared Cu-hemin MOFs/CS-rGO nanocomposites were well characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction, UV–vis spectroscopy and electrochemical techniques. The results showed that after the Cu-hemin MOFs were formed on the CS-rGO surface, the crystalline structure of the Cu-hemin MOFs was kept while the size of Cu-hemin MOFs was decreased and the electrical conductivity of the nanocomposites was enhanced greatly as compared with that of Cu-hemin MOFs. The unique peroxidase-like bioactivity and good electrical conductivity as well as some novel properties of Cu-hemin MOFs/CS-rGO nanocomposites resulted in perfect electrochemical performances towards the reduction of hydrogen peroxide (H 2 O 2 ), superior to some mimic enzymes. The Cu-hemin MOF/CS-rGO was used to construct a novel H 2 O 2 electrochemical sensor which exhibited wide linear range (0.065–410 μM) and low detection limit (0.019 μM). The study might provide a new proposal for preparing perfect hemin-based materials as mimetic peroxidase in the electrochemical sensing.
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POWDER TECHNOLOGY
·
2017
·
IF 2.942
Lanbo Li,Rui Bao,Jianhong Yi,Liang Liu,Shuai Mao
Uniform dispersion of carbon nanotube (CNT) and strong interface combination between nano‑carbon reinforcement and metal matrix are of extremely importance to fabricate CNT/metals composite by powder metallurgy method due to the hereditary effects. Therefore, in this paper, CNT/Cu composite powder was fabricated through Spray Pyrolysis (SP) to improve the dispersity and interface property . Nucleation and growth of Cu grains on the CNT surface occurred in the ultrasonic atomization of acetate (Cu(CH 3 COO) 2 ·H 2 O) solution droplets with mono-dispersed CNT. The microstructures of composite powder were investigated by TGA , Raman, XRD, FESEM and TEM analysis methods. Results show that structural integrity and purity of CNT can be enhanced by SP process at 500 °C. And CNT/Cu composite powder with uniform dispersion and good combination between CNT and Cu particles could be obtained by SP even though high composition of CNT was added. At last, the mechanisms of nucleation and growth were estimated based on the microstructure analysis .
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Journal of Food Measurement and Characterization
·
2016
·Vol. 11
·期 2
·548-555
·
IF 0.521
Xiaohong Zhang,Zhidong Zhao,Xiongwei Lou,Jian Li,Guohua Hui
A maltose, L-rhamnose sensor based on porous Cu foam and electrochemical techniques was investigated in this paper. Cu foam material was prepared and characterized by scanning electron microscopy (SEM). The electro-oxidation reaction process of sweeteners occurred on Cu foam electrode was evaluated by cyclic voltammetry (CV) scanning. At an applied potential of 0.5 V, the linear range for maltose is 0.18–3.47 mM with sensitivity of 1.0492 mA cm −2 mM −1 . The limit of detection (LOD) was 15.86 μM (S/N = 3). The linear range for maltose is 0.18–3.47 mM with sensitivity of 0.6881 mA cm −2 mM −1 . The LOD was 24.18 μM (S/N = 3). Compared with Cu sheet electrode, Cu foam electrode showed higher current response towards maltose and L-rhamnose, leading to enhanced electrocatalytic activity, higher sensitivity, and lower LOD. Sweetener qualitative discrimination was carried out by stochastic resonance (SR) signal-to-noise ratio (SNR) spectrum eigen peak located noise intensities.
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