MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 5
·589-595
·
IF 3.719
Tian Li,Zhang Boxun,Sun Ding,Chen Ruizhan,Wang Binbin,Li Tianjiao
We have fabricated, in a single step, carbon ceramic electrodes modified with a poly(acridine orange) film containing reduced graphene oxide. They display electrocatalytic activity to ascorbic acid (AA) and uric acid (UA) at pH 4.5. The anodic peak potentials of AA and UA are separated by 276 mV so that they can be well resolved in cyclic voltammetry. UA and AA were simultaneously determined in a mixture at working potentials of 170 and 400 mV, respectively. Under optimized conditions, the calibration curves for AA and UA cover the 0.8–5,000 μM and 0.6–900 μM concentration range, respectively, while detection limits are 0.3 μM and 0.2 μM. The electrode was applied to determine AA and UA in urine samples.
DPV curves of RGO–PAO/CCE in the phosphate buffer solution (pH 4.5) containing 5.0 × 10 −5 mol L −1 AA with different concentration of UA (a → f: 0, 1, 3, 5, 7, 9 × 10 −6 mol L −1 )
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2017
·Vol. 312
·期 2
·187-198
·
IF 1.282
Zheng Zhiyang,Wang Youqun,Zhao Wuwei,Xiong Guoxuan,Cao Xiaohong,Dai Ying,Le Zhanggao,Yu Shenglong,Zhang Zhibin,Liu Yunhai
Hydrothermal carbon spheres (HCSs) functionalized with 4-aminoacetophenone oxime group (HCSs-oxime) were prepared by a grafting method and explored to adsorption of uranyl ions from aqueous solution. The results of FT-IR, elemental analysis and zeta potential indicate a successfully modification with oxime group. The adsorbent shows an excellent adsorption capacity (Langmuir, q
m
= 588.2 mg g −1 ) and quick adsorption kinetic (equilibrium time of approximately 60 min) at optimal pH of 6.0. The adsorptive selectivity for uranyl ions has been also great improved in present with various co-existing ions. Overall, HCSs-oxime is a potentially promising material for selective removal of uranium in the contaminated solution.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 12
·1-7
·
IF 5.479
Zhou Jianfeng,Sun Guohan,Pan Jianbin,Pan Yufang,Wang Sumei,Zhai Haiyun
An electrochemical sensor is described for the simultaneous determination of Cd 2+ , Cu 2+ , Hg 2+ and Pb 2+ using square wave anodic stripping voltammetry. A glassy carbon electrode (GCE) was modified with N,N-dimethyl-N-2-propenyl-2-propen-1-aminium chloride homopolymer ionic liquid doped into magnesium(II)-aluminium(III) layered double hydroxides. The morphology investigations suggest that the material possesses typical interconnected laminated micropores and a mesoporous architecture dispersed on the surface of the GCE. This accelerates mass diffusion and facilitates the deposition-stripping process of metal ions. Key operational parameters including pH, deposition potential, deposition time and the quantity of nanomaterial on the GCE were optimized. The following figures of merit for the ions Cd 2+ , Cu 2+ , Hg 2+ and Pb 2+ are obtained under optimum conditions: (a) detection limits of 250, 25, 250 and 16 ng L −1 ; (b) linear ranges from 0.5 to 20, 0.05 to 20, 0.5 to 20 and 0.05 to 20 μg L −1 , and (c) peak potentials of −768, +42, +302 and − 541 mV (vs. Ag/AgCl). The modified GCE was successfully applied to the determination of these ions in spiked black tea extract and in dried tangerine peel .
Schematic representation of novel electrochemical sensor based on a glassy carbon electrode modified with IL-Mg/Al-LDHs composites for the simultaneous detection of Pb 2+ , Cd 2+ , Cu 2+ and Hg 2+ .
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JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
·
2014
·Vol. 91
·期 10
·1783-1792
·
IF 1.62
Han Lijuan,Li Lin,Li Bing,Zhao Lei,Liu Guo-qin,Liu Xinqi,Wang Xuede
High linoleic acid sunflower oil ( HLSO ) with various sitosterol ( Sit ) to lecithin ( Lec ) mass ratios (i.e., 0:100–100:0) were used to develop organogels at two storage temperatures ( T
s : 5 and 25 °C). The results showed that, at 25 °C, the hardness value of organogels obtained from HLSO with both Sit and Lec was higher than that of organogels developed from HLSO with only Sit or Lec . Microscopy revealed that the shapes of the crystals in the organogels varied significantly with the composition of the structurant and the T
s . At both T
s used, the Sit:Lec (80:20) system had a lower degree of supersaturation compared with the (100:0) system. X-ray diffraction (XRD) revealed that Sit:Lec mass ratio of 70:30, 80:20 and 100:0 had similar short spacings, and the presence of Lec might be adverse to the formation of Sit crystal in oil. Small-angel X-ray scattering (SAXS) showed that the layer thickness of Sit/Lec/HLSO organogel was larger than that of Sit/HLSO organogel. It was found that the presence of Lec induced the change of self-assembly structure of Sit in HLSO and caused the changes of physical properties of organogels obtained.
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JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2021
·Vol. 30
·期 3
·855-866
·
IF 3.667
Wang Zhihui,Wang Yanfei,Yao Chen
In this study, Polyethyleneimine modified magnetic chitosan (MCS-PEI) was synthesized by grafting polyethyleneimine onto chitosan and adding magnetic Fe 3 O 4 with sodium polyphosphate as crosslinking agent. The structure of the prepared material was characterized by FT-IR, SEM, EDS, XRD and XPS, which showed MCS-PEI was successfully synthesized. After a series of single factor experiments, the adsorption data fitted well with the Langmuir model ( R 2 = 0.99), being the maximum adsorption capacity equal 181.8 mg g −1 . The pseudo-second-order model ( R 2 = 0.997) and Dubinin-Radushkevich model ( R 2 = 0.9598) indicated that the adsorption process was chemical adsorption. And thermodynamic studies showed that the adsorption was spontaneous and exothermic. The adsorption rate decreased by no more than 4% after the four adsorption–desorption experiments. This work illustrates that MCS-PEI is an environmental friendly, efficient and low-cost adsorbent.
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JOURNAL OF SOLUTION CHEMISTRY
·
2020
·Vol. 49
·期 2
·166-178
·
IF 1.273
Zhu Liqing,Liu Bijun,Yang Xia,Zhuo Liangang,Mu Wanjun,Chen Yue,Yang Yuchuan,Wei Hongyuan,Li Xingliang
Thermodynamic equilibria of complexes of 1,3-diamino-2-hydroxypropane- N , N , N ', N '-tetraacetic acid (DHPTA) with heavy lanthanides (Tb 3+ , Ho 3+ and Lu 3+ ) in aqueous solution have been investigated with potentiometry, spectrophotometry, luminescence spectroscopy and nuclear magnetic resonance spectroscopy (NMR). The results identified three 1:1 Ln/DHPTA (Ln: Tb 3+ , Ho 3+ and Lu 3+ ) complexes with different degrees of deprotonation, LnL − , Ln(H −1 L) 2− , and Ln(OH)(H −1 L) 3− , where H −1 represents the deprotonation of the hydroxyl group between two methyliminodiacetate groups in the DHPTA structure. The alkoxide form of the DHPTA hydroxyl group directly binds to the lanthanide atom, forming highly strong chelation. The complex of Ln(H −1 L) 2− could be present as a dimeric or polymeric complex in solution.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2021
·Vol. 329
·期 3
·1407-1415
·
IF 1.371
Wang Yinghui,Zhao Meng,Zhang Lili,Chen Yuantao
The radioactive iodine in nuclear waste is increasingly polluting the environment, and the careful handling of radioactive iodine is crucial to the sustainable development of nuclear energy. In this paper, a imine-based Covalent organic polymer (COP) is prepared by aldimine condensation. The COP material is stable under 500 MPa ultra-high pressure with an average particle size of 100 μm. The adsorption process is in line with the Langmuir isotherm adsorption model control, and the maximum adsorption capacity is 3082.14 mg/g. The adsorption is a spontaneous endothermic process of increased entropy and raising the temperature is conducive to the adsorption process. The electron donor and iodine electron acceptor in the ligand form an electron transfer compound to achieve iodine adsorption.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2021
·Vol. 248
·期 2
·553-565
·
IF 2.998
Wang Liling,Qin Yuchuan,Wang Yanbin,Liu Bentong,Zhou Yifeng
In this research, the inhibition mechanism of a pairs of homoisoflavonoid analogues (6-aldehydo-isoophiopogonanone A (AIO-A) and 6-aldehydo-isoophiopogonanone B (AIO-B)) on tyrosinase (Tyr) was investigated by multi-spectroscopic techniques combined with molecular docking. The results demonstrated that AIO-A suppressed the activity of Tyr in a reversible competitive-inhibition with a half inhibitory concentration (IC50) of (12.67 ± 2.52) × 10 –5 molˑL −1 , while AIO-B was a reversible mixed-inhibition with IC50 of (4.81 ± 0.74) × 10 –5 molˑL −1 . AIO-A/AIO-B bound to Tyr driven by the intermolecular interactions, including van der Waals interaction, hydrogen bonding and hydrophobic interaction, thereby resulted in a secondary structure change of Tyr and its intrinsic fluorescence quenching. The molecular docking revealed that an aldehyde oxygen atom in AIO-A and methoxyphenyl in AIO-B formed coordination with two Cu ions in the active center of Tyr protein. It can be deduced that the coordination with two Cu ions may prevent the entrance of substrate and then inhibit the catalytic activity of Tyr. The research might provide new perspectives on the inhibition mechanism of AIO-A and AIO-B on Tyr and functional research for the prevention and treatment of pigmented skin diseases and anti-browning of homoisoflavonoids as a food supplement.
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HEAT AND MASS TRANSFER
·
2021
·Vol. 58
·期 3
·407-417
·
IF 2.464
Zhang Dongxue,Wang Xin,Dong Yantao,Lu Nan,Lan Xiaozheng
Normal alkane tetracosane (C 24 ) as a representative compound containing alkyl chains was loaded into various porous materials to obtain form-stable phase change materials (PCMs). In the pores of controlled porous glasses (CPGs), silica gels (SGs), SBA-15 and KIT-6, C 24 acquired tunable phase transition temperatures. By changing the pore sizes, C 24 displayed regulated temperature windows of around 6 K (via melting) and 10 K (via solid phase transition) in the CPGs, 9 K in the SG pores (via melting) and about 13 K in SBA-15 (via melting). Phase transition temperatures, degree of supercooling and enthalpies of phase transitions exhibited linear dependence on the reverse pore diameter. The transition temperature and enthalpy change also had relevance to pore geometries. The phase sequences and solid structures of C 24 in the pores changed largely. The study provides an insight into thermal properties of nano-sized PCMs.
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Science China-Chemistry
·
2024
·
IF 10.4
Chen Xuanwa,Yu Yanhui,Han Xingqi,Wang Huan,Hua Yingjie,Wu Daoxiong,Deng Peilin,Xiao Juanxiu,Tian Xinlong,Li Jing
Seawater electrolysis is an effective way to obtain hydrogen (H 2 ) in a sustainable manner. However, the lack of electrocatalysts with high activity, stability, and selectivity for oxygen evolution reaction (OER) severely hinders the development of seawater electrolysis technology. Herein, sulfur-doped nickel-iron selenide nanosheets (S-NiFeSe 2 ) were prepared by an ion-exchange strategy and served as highly active OER electrocatalyst for alkaline seawater electrolysis. The overpotential is 367 mV, and it can run stably for over 50 h at 100 mA cm −2 . Excitingly, the S-NiFeSe 2 ∥Pt/C pair exhibits cell voltage of 1.54 V at 10 mA cm −2 under alkaline seawater conditions, which can run smoothly for 100 h without decay, and the efficiency of electricity-to-hydrogen (ETH) energy conversion reaches more than 80%. Such electrode, with abundant accessible reactive sites and good corrosion resistance, is a good candidate for seawater electrolysis. Moreover, density functional theory calculations reveal that the surface sulfur atoms can activate the adjacent Ni sites and decrease the free energy changes of the associated intermediates at the adjacent Ni sites for OER, and the step of *OH → *O is the potential rate-limiting step. In this work, the true reactive site in nickel-iron selenides is the Ni sites, but not the Fe sites as commonly believed.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 21
·26097-26104
·
IF 2.478
Shi Bin,Zhao Junjie,Chang Qing
Zeolite X is a potential electromagnetic wave (EMW) absorption material owning to its advantages of good dielectric properties, light weight and large specific surface area. Herein, high-purity zeolite X was prepared from fly ash using a green synthesis approach, in which only trace water was used and achieved zero discharge of waste water. Physiochemical properties of fabricated zeolite X were comprehensively evaluated through XRD, PSD, SEM, TG-DSC and BET test. XRD pattern shows the successful preparation of zeolite X with good crystallinity and high purity, and the average particle size is ~ 2.45 μm, which conforms to Gaussian distributions. The fabricated zeolite X exhibits typical octahedral structure and good thermal stability. It is noteworthy that the specific surface area is up to 473.56 m 2 /g, representing porous structure, which is beneficial to EMW attenuation. What’s more, the abundant crystal water and adsorbed water existing in the sample is conductive to dipole polarization, which further consume EMW energy. The effective absorption bandwidth (EAB) of the synthesized zeolite X is 2.08 GHz (13.36–15.44 GHz) at the thickness of 2.5 mm. This study provides an eco-friendly approach to change waste into valuables, and moreover the synthesized zeolite X is a potential EMW absorbing material.
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IRANIAN POLYMER JOURNAL
·
2020
·Vol. 29
·期 3
·275-286
·
IF 1.707
Shao Ming-lu,Yue Xiang-an,He Jie
To better control the gelation time of in situ polymerization of gel system in reservoir, an activator regenerated by AGET (activator generated by electron transfer) ATRP (atom transfer radical polymerization) initiating system was developed. The AGET ATRP initiating system was composed of an initiator 1,2-dibromoethane, a catalyst ferric chloride and a reducing agent vitamin C, and the effects of these three component proportions on the gelation time and gel viscosity were systematically investigated. Results of bottle tests indicated that the gelation time can even be more than 20 h at 60 °C at optimal concentration ratios. Moreover, the viscosity decreased and the gelation time increased with the increase of salinity and temperature. The gelation time of the core test was 1.5 times or even longer in comparison with that of the bottle test owing to the influences of dilution, adsorption, and rock skeleton isolation. It was also confirmed that the AGET ATRP initiating system can initiate the cross-link gelation of monomers in the core. The enhanced oil recovery result indicated that the oil recovery increased by 9.17% after the gelation of the gelling solutions, and final oil recovery was 40.05%. This research provided a brand-new method to control the gelation time of the in situ polymerization of gel system.
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