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Catalytic ozonation of basic yellow 87 with a reusable catalyst chip
No full textA porous copper fiber sintered sheet (PCFSS) with high porosity and large interfacial area, loaded with Cu/Zn/Al/Zr catalyst (i.e. CuO, ZnO, Al2O3 and ZrO2), was evaluated for catalytic ozonation of Basic Yellow 87 (BY 87) in water. We investigated the influences of temperature, ozone dosage, BY 87 concentration and ozone/BY 87 molar ratios on the kinetics of BY 87 degradation, and the removal efficiency of BY 87. Compared to the ozonation process, the presence of the catalyst chip significantly improved the degradation of BY 87 (two times and five times more effective in the removal efficiency of COD and TOC, respectively). Batch experiments results demonstrated that the catalyst chip could sustain a high removal efficiency of BY 87 (around 99%), COD (about 60%) and TOC (around 30%) under a wide range of temperatures (0.5-61°C), BY 87 concentrations (216-1078ppm) and O3/BY 87 mole ratios (0.98-21.3) within 4h of reaction time. The decomposition rate of BY 87 was enhanced with increasing O3 and BY 87 concentrations under the constant molar ratio. However, a shift from zero-order to pseudo-first-order kinetics (regarding BY 87) was observed when increasing O3/BY 87 mole ratio from 0.98 to a value higher than 2.44. This work also demonstrated that homogeneous and heterogeneous catalytic processes could be integrated together in the presence of the catalyst chip, which shortens the half-life of BY 87 degradation. After reuse of the catalyst chip for ten times, the degradation efficiency of BY 87 and COD remained 99.2% and 58.9%, respectively, indicating a stable activity of the catalyst chip
Hydrothermal self-assembly and supercapacitive behaviors of Co(II) ion-modified graphene aerogels in H2SO4 electrolyte
No full textReduced graphene oxide (r-GO) aerogels decorated with divalent cobalt ions were synthesized via a one-pot hydrothermal self-assembly route. The interaction of Co(II) ions with 3D r-GO aerogels was investigated by spectroscopic techniques, including Raman, attenuated total reflectance infrared, and X-ray photoelectron spectroscopies. The excellent electrochemical properties of the aerogels were confirmed by cyclic voltammetry, galvanostatic charge/discharge tests, and electrochemical impedance spectroscopy in an acid electrolyte (1 M H2SO4). The Co(II) ion-modified r-GO aerogels can be used as high-performance hybrid supercapacitor materials with a specific capacitance of 387.2 F g-1 at 1 A g-1 current density and a good cycling stability without capacity decay over 1000 cycles. The mechanical integrity enhancement of the hybrid r-GO aerogel framework and the improvement in its unique capacitive performance are attributed to the efficient interconnection produced by electro-active Co(II) ions
Chloride ion-driven transformation from Ag3PO4 to AgCl on the hydroxyapatite support and its dual antibacterial effect against Escherichia coli under visible light irradiation
No full textVisible light-driven photocatalytic inactivation of Escherichia coli was performed using hydroxyapatite-supported Ag3PO4 nanocomposites (Ag3PO4/HA). The antibacterial performance was evaluated by the methods of zone of inhibition plates and minimum inhibitory concentration test. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to investigate the instability and transformation of the nanocomposite by comparing the crystalline, phase, and the morphology before and after exposure to Luria-Bertani culture medium under visible light irradiation. Ag3PO4 nanoparticles on the support were found to be shortly transformed into AgCl due to high chloride concentration of Luria-Bertani culture medium. The AgCl/HA nanocomposite showed both excellent intrinsic antibacterial performance contributed by the released silver ions and visible light-induced photocatalytic disinfection toward E. coli cells. This dual antibacterial function mechanism was validated by trapping the hydroxyl free radical and detecting the silver ions during the photocatalytic antibacterial process. The morphological change of E. coli cells in different reaction intervals was obtained by scanning electron microscopy (SEM) to complementally verify photocatalytic inactivation of E. coli. This work suggests that an essential comparison study is required for the antibacterial materials before and after the photocatalytic inactivation of bacterial cells using Ag3PO4 nanoparticles or Ag3PO4-related nanocomposites in mediums containing high-concentration chloride ions
Influence of the surface hydroxyl groups of MnOx/SBA-15 on heterogeneous catalytic ozonation of oxalic acid
No full textComparative ozonation experiments were carried out to investigate the catalytic ability and mechanism of SBA-15 supported manganese oxide (MnOx/SBA-15) for the degradation of oxalic acid (OA) in aqueous solution. The results showed that MnOx/SBA-15 possessed good catalytic capacity for the ozonation of OA. The influences of tert-butanol and phosphate on OA removal and ozone equilibrium concentration in aqueous solution demonstrated that initiation of hydroxyl radicals (radical dotOH) was involved and surface reaction played the major role in O3/MnOx/SBA-15. The effects of manganese content and initial solution pH verified that surface hydroxyl groups affected by the pH of solution and the point of zero charge (pHPZC) of catalysts, were closely related to OA adsorption and radical dotOH initiation on the surface of MnOx/SBA-15. The pre-ozonated catalyst improved its catalytic activity a little due to the enhancement of electron transfer in the presence of higher multivalent MnOx (Mn(III)/Mn(IV)). It was concluded that the protonated surface hydroxyl groups were the main reaction sites and a possible catalytic ozonation mechanism of OA over MnOx/SBA-15 was proposed
Facile preparation and characterization of BiOI-rectorite composite with high adsorptive capacity and photocatalytic activity
No full textRectorite was composited with BiOI to extend its applicability as an applied material with high adsorptive capacity and photocatalytic activity. The facile synthesis process involved ultrasonic irradiation and in situ reaction. The physicochemical properties of the as-prepared samples were characterized by means of X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N 2 adsorption-desorption isotherms, and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). Rhodamine B (RhB), a typical organic contaminant, was used as the model contaminant to evaluate the adsorption capacity and photocatalytic performance of the prepared BiOI-rectorite composite. The adsorption process was found to obey pseudo-second-order kinetics. The equilibrium adsorption was well-modeled using the Freundlich adsorption isotherm. High photocatalytic activity under visible light irradiation was observed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Hierarchical nitrogen-doped porous carbon with high surface area derived from endothelium corneum gigeriae galli for high-performance supercapacitor
No full textEndothelium corneum gigeriae galli derived 3D hierarchical nitrogen-doped porous carbon was for the first time prepared by preliminary carbonization at 450 °C and final KOH activation at high temperatures. The surface and structural properties of the as-synthesized samples are analyzed with Brunauer-Emmett-Teller surface analyzer apparatus, X-Ray Diffractometer, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectrometer. The electrochemical performances are analyzed by cyclic voltammetry, galvanostatic charge/discharge cycling and electrochemical impedance spectroscopy. The obtained results show that the sample carbonized at 900 °C possesses the SSA of 2149.9 m2 g-1, average micropore diameter of 1.78 nm, and exhibits the highest initial specific capacitance of 198.0 F g-1 at current density of 1 A g-1 in 6 M KOH solution. It retains good specific capacitance retention of 91.6% after 3000 charge/discharge cycles at current density of 2 A g-1
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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