ACS Catalysis
·
2016
·
IF 9.307
Jie Sun,Qiuxia Cai,Yan Wan,Shaolong Wan,Li Wang,Jingdong Lin,Donghai Mei,Yong Wang
The promotional effects of a cesium promoter on higher alcohol (C2+OH) synthesis from syngas over Cs2O-Cu/ZnO/Al2O3 catalysts were investigated using a combined experimental and density functional theory (DFT) calculation method. In the presence of a cesium promoter, the C2+OH productivity increases from 77.1 to 157.3 g kgcat–1 h–1 at 583 K due to the enhancement of the initial C–C bond formation. A detailed analysis of chain growth probabilities (CGPs) confirms that initial C–C bond formation is the rate-determining step in the temperature range of 543–583 K. Addition of a cesium promoter significantly increases the productivities of 2-methyl-1-propanol, while the CGP values (C3* to 2-methyl-C3*) are almost unaffected. With the assistance of a cesium promoter, the CGPs of the initial C–C bond formation step (C1* to C2*) increase from 0.13 to 0.25 at 583 K. DFT calculations indicate that the initial C–C bond formation during syngas synthesis over the ZnCu(211) model surface is mainly due to the HCO + HCO coupling. In the presence of Cs2O, the stabilities of key intermediates such as HCO and H2CO are enhanced, which facilitates both HCO + HCO and HCO + H2CO coupling steps with lower activation barriers. In addition, Bader charge analysis suggests that the presence of cesium ions could facilitate nucleophilic coupling between HCO and H2CO for the initial C–C bond formation.
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APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Dan Lv,Yu Liu,Jiasheng Zhou,Kunlun Yang,Zimo Lou,Shams Ali Baig,Xinhua Xu
In this study, a novel bamboo activated carbon (BAC) with ethylene diamine tetraacetic acid (EDTA) functionality was prepared by direct grafting in the presence of tetraethyl orthosilicate (TEOS) as a crosslinking agent. The BAC@SiO 2 -EDTA was characterized by SEM, TEM, TGA, FTIR, XPS and its adsorption property for removal of Pb(II) and Cu(II) under various experimental conditions was also investigated. The characterization results reflected that EDTA was successfully assembled on the surface of the BAC and average pore size increased from 4.10 to 4.83 nm as BAC grafted with EDTA. Adsorption data fitted very well in Langmuir isotherm model and pseudo-second-order kinetic model. As compared with the raw BAC, the maximum adsorption capacities of BAC@SiO 2 -EDTA for the Pb(II) and Cu(II) increased from 45.45 to 123.45 mg g −1 and from 6.85 to 42.19 mg g −1 , since the existence of EDTA on modified BAC promoted the formation of chemical complex. The removal of heavy metal ions mainly depended on the complexation with EDTA and the electrostatic attractions with negatively charged surface of BAC@SiO 2 -EDTA. The adsorption of Pb(II)/Cu(II) on the BAC@SiO 2 -EDTA was pH dependent and pH 5–6 was considered an optimum. However, lower temperature favored the adsorption and the maximum adsorption was recorded at 20 °C. In addition, BAC@SiO 2 -EDTA had an excellent reusability with about 40% decline in the adsorption capacity for Pb(II) after fifth reuse. Insignificant influences of co-existing cations and natural organic matter (NOM) were found on the adsorption of Pb(II) and Cu(II). All the results demonstrate that BAC@SiO 2 -EDTA is a potential adsorbent for metal ions in wastewater.
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JOURNAL OF HAZARDOUS MATERIALS
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2017
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IF 6.065
Qinghua Xu,Yulu Wang,Liqiang Jin,Yu Wang,Menghua Qin
A novel nanocomposite based on black wattle (BW) tannin and nanocellulose was prepared and applied in heavy metal ions adsorptive removal from aqueous solutions. Firstly, nanocrystalline cellulose was oxidized by sodium periodate to get dialdehyde nanocellulose (DANC). BW tannin was then covalently immobilized onto DANC, which was used as both the matrix and crosslinker, to obtain tannin-nanocellulose (TNCC) composite. The resulting nanocomposite was characterized using FTIR, AFM, and TG. The successful immobilization was confirmed by the chromogenic reaction between FeCl 3 and TNCC and FT-IR analysis. AFM images revealed that TNCC was ellipsoidal particles with lengths ranging from 100–400 nm. Zeta potential measurement showed that TNCC was negative charged at a pH range from 1–12. Compared to the original tannin, the thermal stability of TNCC was slightly increased by the addition of nanocellulose. TNCC demonstrated the maximum adsorption efficiency at pH 2 for Cr(VI) and pH 6 for Cu(II) and Pb(II), respectively. The adsorption for these three metal ions followed pseudo second-order kinetics, indicating the chemisorption nature. The adsorption isotherms all fitted well with the Sips model, and the calculated maximum adsorption capacities were 51.846 mg g −1 , 53.371 mg g −1 and 104.592 mg g −1 for Cu(II), Pb(II) and Cr (VI), respectively.
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PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Zhen Shen,Yi Hu,Renzhong Chen,Xia He,Yanli Chen,Hanfeng Shao,Xiangwu Zhang,Keshi Wu
To develop next-generation lithium-ion batteries (LIBs) with novel designs, reconsidering traditional materials with enhanced cycle stability and excellent rate performance is crucial. We herein report the successful preparation of three-dimensional (3D) composites in which spilt Sn–Cu alloys are uniformly dispersed in an amorphous carbon nanofiber matrix (Sn–Cu–CNFs) via one-step carbonization-alloying reactions. The spilt Sn–Cu alloys consist of active Cu 6 Sn 5 and inactive Cu 3 Sn, and are controllable by optimization of the carbonization-alloying reaction temperature. The 3D carbon nanofiber framework allowed the Sn–Cu–CNFs to be used directly as anodes in lithium-ion batteries without the requirement for polymer binders or electrical conductors. These composite electrodes exhibited a stable cyclability with a discharge capacity of 400 mA h g −1 at a high current density of 1.0 A g −1 after 1200 cycles, as well as an excellent rate capability, which could be attributed to the improved electrochemical properties of the Sn–Cu–CNFs provided by the buffering effect of Cu 3 Sn and the 3D carbon nanofiber framework. This one-step synthesis is expected to be widely applicable in the targeted structural design of traditional tin-based anode materials.
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RSC Advances
·
2016
·Vol. 7
·期 1
·318-326
·
IF 3.289
Pham Van Trinh,Nguyen Ngoc Anh,Bui Hung Thang,Le Dinh Quang,Nguyen Tuan Hong,Nguyen Manh Hong,Phan Hong Khoi,Phan Ngoc Minh,Phan Ngoc Hong
In this study, nanofluid based ethylene glycol (EG) containing Cu nanoparticles decorated on a Gr–MWCNT hybrid material (Gr–MWCNT/Cu) was synthesized successfully for the first time via a chemical reduction method. The SEM, HRTEM, FTIR and XRD studies revealed that Cu nanoparticles with an average diameter of 18 nm were well decorated on the surface of both MWCNTs and graphene sheets. The nanofluids containing Gr–MWCNT/Cu material showed good stability and a maximum thermal conductivity enhancement of 41% at 60 °C for the nanofluid containing 0.035 vol% material compared to EG alone. The enhancement is due to the combination of the high thermal conductivity of graphene, CNT and Cu nanoparticles as well as the higher surface area of the Gr–MWCNT/Cu hybrid structure. Experimental results of thermal conductivity were evaluated using different theoretical models, amongst which the Hamilton–Crosser model was found suitable for predicting the thermal conductivity of the nanofluid.
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JOURNAL OF MEMBRANE SCIENCE
·
2016
·
IF 5.557
He Ding,Fusheng Pan,Ena Mulalic,Hassan Gomaa,Weidong Li,Hao Yang,Hong Wu,Zhongyi Jiang,Baoyi Wang,Xingzhong Cao,Peng Zhang
In this study, Cu + and Fe 2+ ions were co-impregnated onto carbon nitride nanosheets via polydopamine chelating, and then incorporated into a Pebax matrix to fabricate the facilitated transport hybrid membranes. The homogeneously dispersed nanosheets disturb the packing of Pebax chains and render the hybrid membrane an appropriate free volume property. The existence of stabilizer Fe 2+ on Cu + Fe 2+ @CNs prevents the disproportionation and oxidation of Cu + , which is an efficient facilitated transport carrier for thiophene via π-complexation in gasoline desulfurization. Accordingly, the hybrid membranes exhibit superior desulfurization performance along with good stability even at high operation temperature. Especially, when the content of Cu + Fe 2+ @CNs is 5 wt%, the membrane achieves the optimum desulfurization performance with a permeation flux of 13.42 kg/(m 2 h) (18.76% higher than that of pure Pebax membrane) and an enrichment factor of 7.11 (28.80% higher than that of pure Pebax membrane) under 60 °C for octane-thiophene model gasoline with thiophene content of 1312 ppm. Besides, the membrane shows good stability in the long-term desulfurization under high operation temperature of 60 °C for 10 days and keeps the stability of incorporated Cu + for six months. The study offers a facile approach to enhance the carrier stability in high-performance facilitated transport membranes.
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CHEMICAL ENGINEERING JOURNAL
·
2014
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IF 4.058
Hai Tao Xing,Jian Hua Chen,Xue Sun,Yi Hong Huang,Zhen Bo Su,Shi Rong Hu,Wen Weng,Shun Xing Li,Hong Xu Guo,Wen Bing Wu,Ya Shan He,Fei Ming Li,Yang Huang
Graphene oxide nanosheets (GO) were dispersed and crosslinked with a water soluble polymer, namely poly(allylamine hydrochloride) (PAH) with high amine density, to prepared a novel PAH-GO composite, which was used for removing Cu(II) ions from aqueous solutions. The physico-chemical properties of PAH-GO composites were investigated by transmission electron microscopy, thermogravimetric analysis, etc. Adsorption experiments indicated that adsorption process was strongly dependent on pH and temperature, however weakly dependent on ionic strength. The maximum adsorption capacity was about 349.03 mg/g higher than that of currently reported. Competitive adsorption studies for the ternary system suggested that the adsorption of PAH-GO composite for Cu(II) ions was much preferable to Cd(II) and Ni(II) ions. Thermodynamic parameters suggested that adsorptions were endothermic and spontaneous processes. The Langmuir adsorption isotherm was applicable fit adsorption process, and adsorption kinetic process could be described by the pseudo-second-order model. Adsorption–desorption results showed that the reusability of PAH-GO composite was encouraging. Based on the results obtained, we conclude that PAH-GO composite can be an effective and potential adsorbent for removing Cu(II) ions from an aqueous solution.
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2015
·Vol. 2015
·期 28
·4731-4736
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IF 2.942
Shuling Xu,Haibo Li,Lei Wang,Qiaoli Yue,Rui Li,Qingwang Xue,Yuanfu Zhang,Jifeng Liu
Graphical Carbon-encapsulated Cu–Ag dimetallic nanoparticles (C–CuAg NPs) were prepared using a facile one-pot route. The formation of C–CuAg NPs involved two steps: (1) the formation of the Cu–Ag alloy and (2) the in situ formation of the carbon layer at a low temperature (120 °C). The as-prepared C–CuAg NPs exhibited high catalytic activity and perfect reusability towards the reduction of 4-nitrophenol. A facile one-pot route has been developed for the synthesis of carbon-encapsulated Cu–Ag dimetallic nanoparticles (C–CuAg NPs). The synthesis was conducted using AgNO 3 and Cu(NO 3 ) 2 as metal precursors and ascorbic acid as the reduction agent and carbon source. The catalytic activities of the C–CuAg NPs for the reduction of 4-nitrophenol (4-NP) with NaBH 4 were tracked by UV/Vis spectroscopy, which demonstrates that the as-prepared C–CuAg NPs exhibit significantly enhanced catalytic activity compared with carbon-encapsulated Cu nanoparticles (C–CuNPs) and carbon-encapsulated Ag nanoparticles (C–Ag NPs). Notably, the catalysts are stable, and there is a high conversion efficiency for at least ten successive cycles. Considering the green facile preparation procedure and high catalytic activity, the prepared C–CuAg NPs hold great promise as highly efficient, cost-effective, and environmentally friendly catalysts for industrial applications.
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NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 13
·5436-5444
·
IF 3.269
Hao Li,Sirong Yu
A superhydrophobic Cu–Zn coating was fabricated on a steel surface by facile one-step electrodeposition, without being chemically modified by a low surface energy material. It was noted that three-level hierarchical structures, just like the surface morphology of a lotus leaf, were formed on the Cu–Zn coating surface via scanning electron microscopy (SEM) images. The water contact angle of the prepared Cu–Zn coating surface was 153.40°, and the sliding angle was less than 10°. From the aspect of chemical composition, it was characterized to confirm that the oxidation of Cu and Zn, and oxygen adsorption were the reasons for the superhydrophobicity. In terms of the surface morphology, based on the classical Wenzel and Cassie models, an idealized three-dimensional (3D) model was fabricated to demonstrate the rationality of the superhydrophobicity without chemical modification. Moreover, this three-level hierarchical Cu–Zn coating had stable superhydrophobicity, excellent self-cleaning properties, and stability.
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MICROCHIMICA ACTA
·
2015
·Vol. 182
·期 13
·2313-2320
·
IF 3.741
Xu Yan,Jin Jingjie,Li Xianliang,Han Yide,Meng Hao,Song Chaosheng,Zhang Xia
We describe a facile method for the preparation of magnetic microparticles consisting of a metal-organic framework (MOF) of Cu(II)-BTC (BTC = 1,3,5-benzenetricarboxylate) for rapid magnetic solid-phase extraction (MSPE) of the dye Congo Red (CR) from aqueous solution. Magnetization of the MOF and solid-phase extraction of CR was simultaneously accomplished by mixing, under ultrasonication, the MOF and silica-coated magnetite microparticles in the solution to be extracted. Under optimized conditions, the magnetic MOF hybrid exhibits a fast adsorption rate and a high removal efficiency (>97 %) toward CR even over 15-fold reuse, which also features high adsorption capacity of 97.7 and 92.5 % for cationinc Methylene Blue (MB) and Crystal Violet (CV), respectively. The desorption of CR from the magnetic MOF was realized by washing it with ethanol and water. The material is considered to be a promising new adsorbent for use in wastewater treatment and in analytical preconcentration.
We report on a method for magnetization of a Cu-BTC metal-organic framework for use in rapid magnetic solid phase extraction of Congo Red from aqueous solutions. The material maintains its high removal efficiency (of >97 %) over 15 recyclable experiments.
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BIORESOURCE TECHNOLOGY
·
2017
·
IF 5.651
Zheng-Zhe Zhang,Jia-Jia Xu,Zhi-Jian Shi,Ya-Fei Cheng,Zheng-Quan Ji,Rui Deng,Ren-Cun Jin
The increasing application of engineered nanoparticles (NPs) has posed an emerging challenge to wastewater treatment processes. The short-term impacts of CuNPs, CuONPs, ZnONPs and AgNPs on anaerobic ammonium oxidation (anammox) process were investigated firstly in this study. CuONPs, ZnONPs and AgNPs up to 50 mg g −1 suspended solid (SS) did not affect anammox activity, reactive oxygen species (ROS) production or cell membrane integrity. However, 1.25 mg g −1 SS CuNPs significantly inhibited the anammox activity and the loads that caused 50% inhibition were 4.64 ± 1.24 and 3.27 ± 0.79 mg g −1 SS for anammox granules and flocs, respectively. 5 mg g −1 SS CuNPs caused serious accumulation of the toxic intermediate N 2 H 4 . Furthermore, CuNPs interacted with extracellular polymeric substances by specifically bonding to tyrosine or tryptophan-containing groups, C-O-C in polysaccharides and –OH in polymeric compounds. Therefore, this study calls for more attention to the risks of NPs to the anammox-based processes.
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 29
·17873-17881
·
IF 3.108
Piyong Zhang,Ting Song,Tingting Wang,Heping Zeng
A broad spectrum absorption photocatalytic system has been expected for a long time, especially for catalysts where the absorption mainly concentrates on the ultraviolet region, like TiO2. Here, dye sensitization was used to realize this expectation for TiO2. Anatase TiO2 was prepared by a hydrothermal method and then modified with Cu nanoparticles (NPs) by chemical reduction reaction. The highest H2 production rate was 3.33 mmol g−1 h−1 for Cu(3%)–TiO2 (content of Cu NPs was 3 wt%) and for pure TiO2 was only 0.356 mmol g−1 h−1. Next, the Cu(3%)–TiO2 photocatalyst was sensitized with various amounts of Erythrosin B (ErB) and the highest H2 production rate was 13.4 mmol g−1 h−1 with 3 mg of ErB in the photoreaction system. Under monochromatic light irradiation (500, 550, 600 and 650 nm), no photocatalytic activity was detected for Cu(3%)–TiO2 and some photocatalytic activities were obtained for sensitized Cu(3%)–TiO2, indicating that ErB sensitization can extend the visible light harvesting ability efficiently. Through photoelectrochemical analysis, electron–hole separation and transfer processes were promoted significantly by modification with Cu NPs and then sensitization by ErB. A possible ErB sensitization mechanism is proposed between ErB and Cu–TiO2 for the improvement of the photocatalytic activity.
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