ACS Applied Materials & Interfaces
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2014
·
IF 5.9
Zhi Chen,Zanyong Zhuang,Qing Cao,Xiaohong Pan,Xiong Guan,Zhang Lin
The mechanism of the interaction between nano-Mg(OH)2 adsorbent and uranyl in water was studied. At trace levels, the uranyl is adsorbed as a monolayer on nano-Mg(OH)2, and occupied a small proportion of the adsorption sites. As the uranyl concentration crosses over a threshold, continuous increase of adsorption capacity takes place. It indicates that, by taking the pre-adsorbed uranyl as the nucleation centers, the additional uranyl crystallizes and forms U-rich nanocrystals well-scattered on the surface of nano-Mg(OH)2. A strategy of inducing fast crystal growth of nano-Mg(OH)2 to micrometer-sized Na2Mg(CO3)2 enables the desorption and enrichment of uranyl. The recycling and reuse of nano-Mg(OH)2 can be achieved simultaneously. The finding in this work provides fundamental understanding of the efficient usage of nano-Mg(OH)2 in practical applications.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
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2014
·Vol. 19
·期 1
·229-239
·
IF 2.234
Zhang J. L.,Liu H. D.,Huang L. H.,Tan S. Z.,Mai W. J.,Cai X.
An advanced electrochemical pseudocapacitor material based on reduced graphene oxide and nickel hydroxide (rGO&Ni(OH) 2 ) was prepared by an easy process where ammonia acted as a pre-stabilizer that could be easily removed. The results showed that the agglomeration and re-stacking of rGO could be effectively prevented, resulting in few-layer rGO nanosheet with high specific surface area of 891.22 m 2 /g which could supply large available area for loading nanoparticle. After the incorporation of Ni(OH) 2 nanoparticle, the rGO&Ni(OH) 2 composite owned excellent electrochemical performance thanks to effective prevention of agglomeration and re-stacking of rGO with large size of the sp 2 domain, no residual of pre-stabilizer of ammonia, and tight contact between rGO and Ni(OH) 2 . Specifically, the rGO&Ni(OH) 2 electrode exhibited excellent stability at scan rates from 100 to 300 mV/s. A high specific capacitance of 1,008 F/g was obtained at high current density of 42 A/g in 6 mol/L KOH aqueous electrolyte, and the specific capacitance demonstrated good rate capability. Moreover, rGO&Ni(OH) 2 electrode showed a long cycle life, retaining 74 % specific capacitance after 2,000 cycles at current density of 6 A/g. The advantages of easy process and excellent electrochemical property suggested great potential application of rGO&Ni(OH) 2 in supercapacitors.
An advanced electrochemical pseudocapacitor material based on reduced graphene oxide and nickel hydroxide was prepared by an easy process where ammonia acted as a pre-stabilizer that could be easily removed. The obtained material owned excellent electrochemical property, including high capacitance, good rate capability, excellent stability, long cycle life, etc.
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MATERIALS CHEMISTRY AND PHYSICS
·
2014
·
IF 2.129
Feng Xu,Shuang Guo,Yan-Ling Luo
Novel polyurethane (PU) conducting composite thin films based on tetrahydroxyl-terminated poly(butadiene- co -acrylonitrile) (THTBN) and hydroxyl-functionalized multi-walled carbon nanotubes (MWNTs-OH), were prepared via an in-situ coupling reaction route between hydroxyl groups and isocyanate groups. The chemical and crystal structures were characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). The morphologies and the dispersion behavior of THTBN/MWNTs-OH were examined by scanning electron microscope (SEM), transmission electron microscopy (TEM) and UV–Vis measurements. The influence of MWNTs-OH loading amount on conducting properties and response to some volatile organic compounds (VOCs) especially benzene and toluene was investigated. The experimental results indicated that MWNTs-OH was tightly encapsulated by PU moieties and homogeneously dispersed in the PU moieties. The as-prepared THTBN/MWNTs-OH PU conducting thin films exhibited strong and selective response to nonpolar benzene and toluene vapors, and the response depends on the loading of MWNTs-OH and VOC vapor concentrations. The improvement in dispersity and sensing properties were closely correlated with the chemical linkage of MWNTs-OH in the THTBN matrices through bridging molecules HDI. The developed PU conducting thin films had fast response and reversibility, significant reproducibility and long-term stability. Therefore, they had a possibility as a candidate of volatile organic solvent vapor sensors.
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GREEN CHEMISTRY
·
2015
·Vol. 17
·期 5
·2888-2895
·
IF 8.02
Jian-hua Guo,Guang-yue Xu,Fei Shen,Yao Fu,Ying Zhang,Qing-xiang Guo
The long-chain alkanes obtained from the hydrodeoxygenation of plant oils are ideal substitutes for diesel. In this work, a new efficient catalytic system was established for the conversion of plant oil to long-chain alkanes under mild conditions with a bi-functional Ru/La(OH)3 catalyst. The hydrodeoxygenation of stearic acid was performed in an autoclave with Ru-based catalysts with different supports (HZSM-5, ZSM-5, SiO2–Al2O3, SiO2, ZrO2, Mg(OH)2, La(OH)3, and La2O3). Among these catalysts, Ru supported on basic La(OH)3 showed a remarkable catalytic performance for the reaction. Over 98% of long-chain alkanes were obtained with 100% conversion of stearic acid at 200 °C and 4 MPa H2. When crude Jatropha oil was hydrogenated, about 80.7 wt% of long chain alkanes were obtained under the optimized conditions (200 °C, 4 MPa H2, 8 h). The high efficiency of the Ru/La(OH)3 catalyst could be due to a co-effect of the high hydrogenation activity of Ru and the basic La(OH)3 support which can attract the acidic raw material. Additionally, the Ru/La(OH)3 catalyst was recycled four times and maintained a good activity and stability. The reaction pathway was also explored by using stearic acid as a model compound. Hydrogenation–decarbonylation could be the main pathway to produce n-heptadecane, which has one carbon atom less than stearic acid.
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RSC Advances
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2015
·Vol. 6
·期 6
·4329-4334
·
IF 3.84
Jikui Wang,Jiahong Guo,Pengxiang Si,Wanping Cai,Yuming Wang,Genhua Wu
An In(OH)3–PDMS sponge has been synthesized by covalent modification of PDA. The sponge can switch surface wettability reversibly between superhydrophobicity and superhydrophilicity when detecting ammonia. The water contact angle changes from 141.5° to 0° after storage in an ammonia atmosphere, which means an ammonia responsive surface wettability switch. The minimum NH3·H2O concentration that the In(OH)3–PDMS can detected is 5% in 2 h. This kind of quick and sensitive ammonia detector is promising simply by virtue of the surface wettability conversion.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2014
·Vol. 52
·期 19
·2715-2724
·
IF 3.245
Jizhen Zhang,Aihua Li,Huihui Liu,Dongjiang Yang,Jingquan Liu
A recyclable solid-state photoinitiator based on the surface modified niobium hydroxide is prepared and successfully introduces into reversible addition–fragmentation chain transfer (RAFT) polymerization under visible light illumination. It is revealed by gel permeation chromatography analysis that well-defined polymers with controlled molecular weight and narrow polydispersity index can be achieved when the feed ratio of photoinitiator to the RAFT agent was controlled properly. It is also found that the polymerization is highly responsive to external stimulus and when light is removed from the system polymerization stops almost immediately. In addition, the photoinitiator can be recycled and reused to initiate the polymerization for many times without significant decrease of initiation efficiency. At last, the mechanism for the light initiated polymerization is proposed to illuminate how the initiation and chain propagation proceed. This facile, green and visible light initiation methodology could attract more and more applications in polymer science with the depletion of fossil energy. A recyclable solid-state photoinitiator based on the surface modified niobium hydroxide was prepared and successfully introduced into reversible addition–fragmentation chain transfer (RAFT) polymerization under visible light illumination. It is revealed that well-defined polymers with controlled molecular weight and narrow polydispersity index (PDI) can be achieved when the feed ratio of photoinitiator to the RAFT agent was controlled properly. It is also found that the polymerization is highly responsive to light initiation. In addition, the photoinitiator can be recycled and reused to initiate the polymerization for many times without significant decrease of initiation efficiency. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 2715–2724
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Chemistry Central Journal
·
2017
·Vol. 11
·期 1
·1-8
·
IF 2.442
Xie Yulu,Li Xican,Xu Jieying,Jiang Qian,Xie Hong,He Jianfeng,Chen Dongfeng
Background
Suoyang originates from a psammophyte named Cynomorium songaricum Rupr and has been known as a phenolic-antioxidant-enriched traditional Chinese herbal medicine. The present study attempted to investigate the protective effect of phenolic antioxidants in Suoyang towards •OH-mediated MSCs and then further discusses the chemical mechanisms.Methods The lyophilized aqueous extract of Suoyang (LAS) was prepared and characterized using HPLC. Then, two phenolic antioxidant references, epicatechin and luteolin-7-O-β-D-glucoside, along with LAS, were investigated for their effects on the viability of •OH-treated MSCs using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The comparison and mechanistic chemistry of epicatechin and luteolin-7-O-β-D-glucoside were further explored using various antioxidant assays, including PTIO•-scavenging, FRAP (ferric ion reducing antioxidant power), ABTS+•-scavenging, and DPPH•-scavenging. Their Fe2+-binding capacities were also compared using ultraviolet (UV) spectra.Results The HPLC analysis indicated that there are 8 phenolic antioxidants in LAS, including epicatechin, luteolin-7-O-β-D-glucoside, gallic acid, protocatechuic acid, catechin, isoquercitrin, phlorizin, and naringenin. The MTT assay revealed that epicatechin could more effectively increase the survival of •OH-treated MSCs than luteolin-7-O-β-D-glucoside. Similarly, epicatechin exhibited higher antioxidant abilities than luteolin-7-O-β-D-glucoside in the DPPH•-scavenging, ABTS+•-scavenging, FRAP, and PTIO•-scavenging assays. In the Fe2+-binding assay, luteolin-7-O-β-D-glucoside gave a stronger UV peak at 600 nm, with ε = 2.62 × 106 M−1 cm−1, while epicatechin produced two peaks at 450 nm (ε = 8.47 × 105 M−1 cm−1) and 750 nm (ε = 9.68 × 105 M−1 cm−1).Conclusion As two reference antioxidants in Suoyang, epicatechin and luteolin-7-O-β-D-glucoside can enhance the viability of •OH-damaged MSCs. Such a beneficial effect may be from their antioxidant effects, including direct-antioxidant and indirect-antioxidant (i.e., Fe2+-binding) processes. In the direct-antioxidant process, proton (H+), one electron (e), or even hydrogen-atom (•H) transfer may occur to fulfill radical-scavenging (especially •OH-scavenging); in this aspect, epicatechin is superior to luteolin-7-O-β-D-glucoside due to the presence of more phenolic –OHs. The additional –OHs can also be responsible for the better cytoprotective effect. In terms of indirect-antioxidant potential, however, epicatechin is inferior to luteolin-7-O-β-D-glucoside due to the absence of a hydroxyl-keto moiety. These findings will provide new information about medicinal psammophytes for MSC transplantation.
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ADVANCED POWDER TECHNOLOGY
·
2017
·
IF 2.659
Wenle Ma,Yongmei Feng,Li Wang,Yanhong Li,Min Shi,Hongtao Cui
In this work, we report the preparation of Co 2 (OH) 3 Cl nanoparticles with average size of ∼20 nm and well-defined cubic shape at room temperature by an epoxide precipitation route. It was found that the as-prepared Co 2 (OH) 3 Cl nanoparticles could be used as a promising new electrode material for application in redox supercapacitors due to its high electrochemical performance. It presented superior specific capacitance of 783 F g −1 at low current density of 2.8 A g −1 , while it had a high value of 604 F g −1 at high current density of 56.6 A g −1 , proving its excellent high rate performance. Its 75% capacitance retention after 10,000 cycles of charge–discharge demonstrated its long-life span. According to characterization results, the possible mechanism for the electrochemical process that Co 2 (OH) 3 Cl nanoparticles underwent was proposed as a process of Co 2 (OH) 3 Cl → β-Co(OH) 2 → CoOOH ↔ Co 3 O 4 .
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JOURNAL OF HAZARDOUS MATERIALS
·
2016
·
IF 4.836
Shunlong Pan,Jiansheng Li,Gaojie Wan,Chao Liu,Wenhong Fan,Lianjun Wang
In this work, Fe 3 O 4 @Zr(OH) x yolk–shell nanospheres (YSNs) were synthesized via a two-step process and further examined as adsorbents for the removal of Pb(II). To understand the hollow structure on the adsorption properties of Pb(II), another adsorbent without hollow cavities, i.e., Fe 3 O 4 @SiO 2 @Zr(OH) x core–shell nanospheres (CSNs), was also prepared for comparison. The adsorption results showed that Fe 3 O 4 @Zr(OH) x YSNs exhibited 41.6% higher Pb(II) adsorption capacity as compared to that of Fe 3 O 4 @SiO 2 @Zr(OH) x CSNs. The isotherm was well fitted to Langmuir adsorption model with q max value of 310.8 mg/g after normalized by the weight of Zr in Fe 3 O 4 @Zr(OH) x YSNs. Scanning transmission electron microscopy (STEM) mapping results revealed that the existence of cavities between Fe 3 O 4 cores and Zr(OH) x shells is responsible for the improved adsorption performance. XPS analysis indicated the surface hydroxyl groups played a key role in the Pb(II) adsorption. The removal efficiency of Pb(II) was maintained above 90% in five consecutive adsorption–desorption cycles.
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Zijiong Li,Weiyang Zhang,Chunyan Sun,Zhifu Feng,Baocheng Yang
It has shown better electrochemical performance to use two dimensions (2D) nanomaterial nickel hydroxide nanosheets as electrode materials in energy storage research. However, when compared with carbon electrode material, the disadvantage of metal hydroxide is more obvious. In this study, we use Ni(OH) 2 /rGO composites (NGCs) synthesized by hydrothermal method as electrode materials to conduct an electrochemical property tests in 6 M KOH electrolyte solution . As a result, when current density of NGC 8 samples (the mass ratio of Ni(OH) 2 and graphene is 8:1) is 0.8 A g −1 , the largest specific capacitance of composites is 1862.2 F g −1 . What’s more, when the current density is 15 A g −1 , the capacitance only reduced to 91.6% after the constant current charge and discharge for 2000 cycles, which showed magnificent cycling stability. Further investigations, the 2D nanomaterial NGCs can be easily transmitted to NrCs (NiO/rGO composites), and delivers a specific capacitance of 782.5 F g −1 at a current density of 0.5 A g −1 . These works are of great significance for the research of energy storage materials and the development of energy storage device.
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MOLECULES
·
2016
·Vol. 21
·期 9
·1246
·
IF 2.465
Xican Li,Qian Jiang,Tingting Wang,Jingjing Liu,Dongfeng Chen
The role of the 6″-OH (ω-OH) group in the antioxidant activity of flavonoid glycosides has been largely overlooked. Herein, we selected quercitrin (quercetin-3-O-rhamnoside) and isoquercitrin (quercetin-3-O-glucoside) as model compounds to investigate the role of the 6″-OH group in several antioxidant pathways, including Fe2+-binding, hydrogen-donating (H-donating), and electron-transfer (ET). The results revealed that quercitrin and isoquercitrin both exhibited dose-dependent antioxidant activities. However, isoquercitrin showed higher levels of activity than quercitrin in the Fe2+-binding, ET-based ferric ion reducing antioxidant power, and multi-pathways-based superoxide anion-scavenging assays. In contrast, quercitrin exhibited greater activity than isoquercitrin in an H-donating-based 1,1-diphenyl-2-picrylhydrazyl radical-scavenging assay. Finally, in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl assay based on an oxidatively damaged mesenchymal stem cell (MSC) model, isoquercitrin performed more effectively as a cytoprotector than quercitrin. Based on these results, we concluded that (1) quercitrin and isoquercitrin can both indirectly (i.e., Fe2+-chelating or Fe2+-binding) and directly participate in the scavenging of reactive oxygen species (ROS) to protect MSCs against ROS-induced oxidative damage; (2) the 6″-OH group in isoquercitrin enhanced its ET and Fe2+-chelating abilities and lowered its H-donating abilities via steric hindrance or H-bonding compared with quercitrin; and (3) isoquercitrin exhibited higher ROS scavenging activity than quercitrin, allowing it to improve protect MSCs against ROS-induced oxidative damage.Keywords:quercitrin;isoquercitrin;Q3G;6″-OH;ω-OH;flavonoid glycoside;antioxidant mechanisms;mesenchymal stem cells
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CHEMOSPHERE
·
2024
·
IF 8.1
Linxin Zheng,Ningchao Zheng,Zhizeng Pan,Guang Gao,Chao He,Xinran Mou,Xiangbiao Yin,Shunyan Ning,Mohammed F. Hamza,Yuezhou Wei
Efficient recovery of uranium from wastewater and seawater provides an important guarantee for the sustainable growth of nuclear energy. Herein, we skillfully use the alkali etching method to construct CeO 2 hollow spheres rich in Ce–OH groups for the removal and recovery of uranium from water matrixes. It is found that the CeO 2 exhibits fast adsorption kinetics (equilibrium time within 10 min) and moderate adsorption capacity (143.1 mg/g), and the removal efficiency of low concentration uranium (0.1 g/L and 1 g/L) reaches 100% within 1 min of adsorption. Moreover, the adsorption of uranium by CeO 2 is almost unaffected by common anions and cations in the environment, even if the concentration of anions is 1000 times that of uranium. More importantly, the CeO 2 can enrich uranium concentration in seawater by 167.9 times and the recovery rate reaches 83.9%. Mechanistic studies reveal that the adsorption of uranium by CeO 2 is mainly attributed to the rich Ce–OH groups on the surface of CeO 2 , resulting in the rapid adsorption of U(VI) and mainly forms a single-bridge model. The findings of this study provide a green and efficient path for the removal and recovery of uranium from wastewater and seawater.
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