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Sana El-Kacemi, Hicham Zazou, Nihal Oturan, Matthias Dietze, Mohamed Hamdani, Mohammed Es-Souni, Mehmet A Oturan
Electrochemical oxidative degradation of diazo dye Amido black 10B (AB10B) as model pollutant in water has been studied using nanostructured ZnO-TiO2 thin films deposited on graphite felt (GrF) substrate as anode. The influence of various operating parameters, namely the current intensity, the nature and concentration of catalyst, the nature of electrode materials (anode/cathode), and the adsorption of dye and ambient light were investigated. It was found that the oxidative degradation of AB10B followed pseudo first-order kinetics...
October 25, 2016: Environmental Science and Pollution Research International
Xiubo Xie, Yu Pang, Hiroaki Kikuchi, Tong Liu
25 nm carbon-coated microporous Co/CoO nanoparticles (NPs) were synthesized by integrating chemical de-alloying and chemical vapor deposition (CVD) methods. The NPs possess micropores of 0.8-1.5 nm and display a homogeneous carbon shell of about 4 nm in thickness with a low graphitization degree. The saturation magnetization (MS) and coercivity (HC) of the NPs were 70.3 emu g(-1) and 398.4 Oe, respectively. The microporous Co/CoO/C NPs exhibited enhanced microwave absorption performance with a minimum reflection coefficient (RC) of -78...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
Filipa R Fernandes Simoes, Nitin Kumar Batra, Bashir H Warsama, Christian G Canlas, Shashikant Pandurang Patole, Tahir F Yapici, Pedro M F J Costa
Inductively coupled plasma optical emission spectroscopy (ICP-OES) is a common, relatively low cost and straightforward analytical technique for the study of trace quantities of metals in solid materials but its applicability to nanocarbons (e.g. graphene and nanotubes) has suffered from the lack of efficient digestion steps and certified reference materials (CRM). Here, various commercial and certified graphitic carbon materials were subjected to a "two-steps" microwave-assisted acid digestion procedure and the concentration of up to 18 elements was analysed by ICP-OES...
October 25, 2016: Analytical Chemistry
Feng Peng, Jorge Botana, Yanchao Wang, Yanming Ma, Mao-Sheng Miao
Xenon difluoride is the first and the most stable of hundreds of noble-gas (Ng) compounds. These compounds reveal the rich chemistry of Ngs. No stable compound that contains a Ng-Ng bond has been reported previously. Recent experiments have shown intriguing behaviors of this exemplar compound under high pressure, including increased coordination numbers and an insulator-to-metal transition. None of the be-haviors can be explained by electronic-structure calculations with fixed stoichiometry. We therefore con-ducted a structure search of xenon-fluorine compounds with various stoichiometries, and studied their stabili-ties under pressure using first principles calculations...
October 24, 2016: Journal of Physical Chemistry Letters
J Rodrigo Magana, Yury V Kolen'ko, Francis Leonard Deepak, Conxita Solans, Rekha Goswami Shrestha, Jonathan P Hill, Katsuhiko Ariga, Lok Kumar Shrestha, Carlos Rodriguez-Abreu
Carbon nanofibers (CNFs) with high surface area (820 m2/g) have been successfully prepared by a nanocasting approach using silica nanofibers obtained from chromonic liquid crystals as a template. CNFs with randomly oriented graphitic layers show outstanding electrochemical supercapacitance performance exhibiting a specific capacitance of 327 F/g at a scan rate of 5 mV/s with long life cycling capability. Approximately 95% capacitance retention is observed after 1000 charge-discharge cycles. Furthermore, about 80% of capacitance is retained at higher scan rates (up to 500 mV/s) and current densities (from 1 to 10 A/g)...
October 24, 2016: ACS Applied Materials & Interfaces
Teng Wang, Yanru Guo, Zhenxing Zhou, Xinghua Chang, Jie Zheng, Xingguo Li
Developing noble-metal-free catalysts for electrochemical hydrogen evolution reactions (HER) with superior stability in acid is of critical importance for large-scale, low-cost hydrogen production from water electrolysis. Herein, we report a highly efficient and stable noble-metal-free HER catalyst, which is composed of Ni and Mo2C nanocrystals supported on N-doped graphite nanotubes. This catalyst shows very low overpotential (65 mV in 0.5 M H2SO4 at a current density of 10 mA cm(-2) with a Tafel plot of 67 mV/dec) and good stability for HER in acidic electrolyte, which is a promising noble-metal-free HER catalyst...
October 24, 2016: ACS Nano
Marta Sevilla, Guillermo A Ferrero, Antonio B Fuertes
A facile and environmentally friendly synthetic strategy for the production of stable and easily processable dispersions of graphene in water is presented. This strategy represents an alternative to classical chemical exfoliation methods (for example the Hummers method) that are more complex, harmful, and dangerous. The process is based on the electrochemical exfoliation of graphite and includes three simple steps: 1) the anodic exfoliation of graphite in (NH4 )2 SO4 , 2) sonication to separate the oxidized graphene sheets, and 3) reduction of oxidized graphene to graphene...
October 24, 2016: Chemistry: a European Journal
Masahiro Shibuta, Kazuo Yamamoto, Tsutomu Ohta, Masato Nakaya, Toyoaki Eguchi, Atsushi Nakajima
Time-resolved two-photon photoemission (TR-2PPE) spectroscopy is employed to probe the electronic states of a C60 fullerene film formed on highly oriented pyrolytic graphite (HOPG), acting as a model two-dimensional (2D) material for multi-layered graphene. Owing to the in-plane sp(2)-hybridized nature of the HOPG, the TR-2PPE spectra reveal the energetics and dynamics of photocarriers in the C60 film: after hot excitons are nascently formed in C60 via intramolecular excitation by a pump photon, they dissociate into photocarriers of free electrons and the corresponding holes, and the electrons are subsequently detected by a probe photon as photoelectrons...
October 24, 2016: Scientific Reports
Anna Laura Capriotti, Chiara Cavaliere, Patrizia Foglia, Giorgia La Barbera, Roberto Samperi, Salvatore Ventura, Aldo Laganà
Recently, magnetic solid-phase extraction has gained interest because it presents various operational advantages over classical solid-phase extraction. Furthermore, magnetic nanoparticles are easy to prepare, and various materials can be used in their synthesis. In the literature, there are only few studies on the determination of mycoestrogens in milk, although their carryover in milk has occurred. In this work, we wanted to develop the first (to the best of our knowledge) magnetic solid-phase extraction protocol for six mycoestrogens from milk, followed by liquid chromatography and tandem mass spectrometry analysis...
October 24, 2016: Journal of Separation Science
Korbua Chaisiwamongkhol, Kamonwad Ngamchuea, Christopher Batchelor-McAuley, Richard G Compton
We demonstrate the potential of electrochemical detection for the analysis of the 'strength' of ginger in ginger sample. This facile and fast detection method is aimed at the quality control in food industry. Specifically, we report adsorptive stripping voltammetry (AdsSV) as a technique for detection of gingerol compounds, the pungent components of ginger rhizome. Among the gingerols, 6-gingerol is the most abundant and is chosen as a model to characterise the behaviour of a wider range of related compounds...
October 24, 2016: Analyst
Jesús Marín-Sáez, Roberto Romero-González, Antonia Garrido Frenich
A new method has been developed for the enantioselective separation of (-) and (+) hyoscyamine in Solanaceaes seeds and contaminated buckwheat. Chromatographic separation was optimized, evaluating two chiral columns, Chirobiotic V and Chiralpal-AY3. Better resolution was obtained using a Chiralpak-AY3 column, utilizing as mobile phase ethanol (0.1% diethanolamine). An extraction procedure based on a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) was applied, using water and acetonitrile containing 1% of acetic acid, and a clean-up step utilizing primary secondary amine (PSA) and graphitized carbon black (GCB) as sorbents...
October 19, 2016: Journal of Chromatography. A
Dang Van Thanh, Phung Phi Oanh, Do Tra Huong, Phuoc Huu Le
We present a novel and highly efficient method for exfoliating of graphite to produce graphene via the synergistic effects of in-situ plasma induced electrochemical exfoliation with ultrasonic energy, called ultrasonic-assisted cathodic electrochemical discharge. This method can work at moderate temperatures without the need of acidic media or expensive ionic electrolyte. The produced graphene exhibited a large lateral dimension of approximately 6μm and a thickness of 2.5nm, corresponding to approximately seven layers of graphene...
January 2017: Ultrasonics Sonochemistry
Francesca Veronesi, Gianluca Giavaresi, Milena Fini, Giovanni Longo, Caterina Alexandra Ioannidu, Anna Scotto d'Abusco, Fabiana Superti, Gianluca Panzini, Carlo Misiano, Alberto Palattella, Paolo Selleri, Nicola Di Girolamo, Viola Garbarino, Laura Politi, Roberto Scandurra
Titanium implants coated with a 500nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
K Thenmozhi, S Sriman Narayanan
The enzyme horseradish peroxidase and the water-soluble mediator toluidine blue were covalently immobilized to 3-aminopropyl trimethoxy silane precursor through glutaraldehyde crosslinker. A rigid ceramic composite electrode was fabricated from this modified silane along with graphite powder, which resulted in an amperometric biosensor for H2O2. The electrochemical behaviour of the modified biosensor was monitored using cyclic voltammetry in the potential range of 0.2V to -0.4V vs SCE. The biosensor exhibited a stable voltammogram with cathodic peak at -0...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Qian Gao, Weixiao Chen, Yin Chen, David Werner, Gerard Cornelissen, Baoshan Xing, Shu Tao, Xilong Wang
The ability of multiwalled carbon nanotubes (MWCNTs) to remove a non-ionic surfactant, Triton X-100 (TX100), an anionic surfactant, sodium dodecylbenzenesulonate (SDBS), and a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB) from the aqueous phase was investigated. Untreated, OH-, and COOH-functionalized MWCNTs with different outer diameters and chemical composition were examined and compared. As both the concentrations of surfactants and MWCNTs initially added may affect removal efficiency of surfactants, a relationship between the initial concentration ratio of surfactants and MWCNTs (Rc) and the removal efficiency (E) was established...
October 11, 2016: Water Research
Ariane Isis Barros, Diego Victor de Babos, Edilene Cristina Ferreira, José Anchieta Gomes Neto
Different precursors were evaluated for the generation of reference spectra and correction of the background caused by SiO molecules in the determination of Sb in facial cosmetics by high-resolution continuum source graphite furnace atomic absorption spectrometry employing direct solid sample analysis. Zeolite and mica were the most effective precursors for background correction during Sb determination using the 217.581nm and 231.147nm lines. Full 2(3) factorial design and central composite design were used to optimize the atomizer temperature program...
December 1, 2016: Talanta
R Rapini, A Cincinelli, G Marrazza
In this work, we propose an electrochemical DNA aptasensor for sensitive multidetection of acetamiprid based on a competitive format and disposable screen-printed arrays. To improve the sensitivity of the aptasensor, polyaniline film and gold nanoparticles were progressively electrodeposited on the graphite screen-printed electrode surface by cyclic voltammetry. Gold nanoparticles were then employed as platform for thiol-tethered DNA aptamer immobilization. Different acetamiprid solutions containing a fixed amount of biotinylated complementary oligonucleotide sequence by DNA aptasensor arrays were analyzed...
December 1, 2016: Talanta
Kunfeng Chen, Dongfeng Xue, Sridhar Komarneni
Nanoclay assisted electrochemical exfoliation was developed to in-situ form functionalized graphene electrode materials from pencil core with different ratios of graphite and clay. This method made a positive transformation from solid graphite to graphene colloidal solution, which can be used to construct binder- and additive-free thin-film electrodes. Exfoliated graphene can be served as both conductive current collector (film resistance of 33Ω/square) and electrode materials. Graphene thin-film electrodes from pencil cores displayed higher capacity of 224 than 80mAh/g of that from pure graphite...
October 15, 2016: Journal of Colloid and Interface Science
Chellakannu Rajkumar, Balamurugan Thirumalraj, Shen-Ming Chen, His-An Chen
In this study, we demonstrate a simple preparation of graphite (GR) sheets assisted with gelatin (GLN) polypeptide composite was developed for sensitive detection of dopamine (DA) sensor. The GR/GLN composite was prepared by GR powder in GLN solution (5mg/mL) via sonication process. The prepared GR/GLN composite displays well dispersion ability in biopolymer matrix and characterized via scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS) studies...
October 14, 2016: Journal of Colloid and Interface Science
Isabel P G Fernandes, Ana Maria Oliveira-Brett
Calmodulin (CaM) is an essential protein present in all eukaryote cells, ranging from vertebrates to unicellular organisms. CaM is the most important Ca(2+) signalling protein, composed of two domains, N- and C-terminal domains, linked by a flexible central α-helix, and is responsible for the regulation of numerous calcium-mediated signalling pathways. Four calcium ions bind to CaM, changing its conformation and determining how it recognizes and regulates its cellular targets. The oxidation mechanism of native and denatured CaM, at a glassy carbon electrode, was investigated using differential pulse voltammetry and electrochemical impedance spectroscopy...
October 7, 2016: Bioelectrochemistry
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