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Fabrication of new metal-free materials for the hydrogen evolution reaction on base of the acridine derivatives immobilized on carbon materials
摘要： The process of adsorption on carbon material (Vulcan XC-72 (VU)) of organic heterocyclic compounds: acridine (I) and its derivatives 9-phenylacridine (II) and N-methyl-9-phenylacridium iodide (III) was studied in detail. Quantitative data on physical adsorption were obtained for all compounds. Based on the adsorption isotherms of Langmuir, the adsorption equilibrium constants K, the parameter A∞ and ΔG0 ad were calculated. It has been shown that the adsorption of compounds I and II is a structurally dependent process that depends on the nature and size of the functional substituents in the molecule, and the adsorption of compound III has a complex mechanism and partially proceeds through the stabilization stage by the functional groups present on the surface (-COOH, -COH, -OH). With the use of quantum chemical calculations, it has been established that the process of adsorption of compounds on the surface of a carbon materials having sections with a graphite-like structure is thermodynamically unprofitable because of the high difference in the energies of the adsorbent's boundary orbitals and the substrate. Using the cyclic voltammetry method, the electrochemical properties of organic compounds immobilized on the surface of a carbon material were studied.
关键词： Electocatalysis,Acridine derivatives,Immobilization,Adsorption,Carbon materials,Hydrogen evolution reaction
更新于2025-09-23 15:22:29
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Novel RGO and concave cube Cu <sub/>2</sub> O co-modified BiVO <sub/>4</sub> nanosheets with enhanced photocatalytic and surface adsorption performances of tetracycline
摘要： A novel ternary Cu2O/BiVO4/RGO photocatalyst is successfully constructed by hydrothermal and evaporation-induced method, and it exhibits superior photocatalytic performance for degradation tetracycline (TC). Meanwhile, the visible light absorption range of composite photocatalyst is effectively broadened by the formation of heterojunction with narrow band gap semiconductor Cu2O. And the separation efficiency of the photogenerated electron-hole pairs is significantly enhanced by the synergistic effect of Cu2O and RGO. More importantly, the adsorption of TC by ternary Cu2O/BiVO4/RGO possesses high adsorption capacity, which is 23.73 times higher than that of pure BiVO4. Additionally, the possible reaction mechanism is clearly revealed by radical trapping experiment, electron spin-resonance (ESR) spectroscopy. This work provides a new insight to design a photocatalyst with excellent adsorption to remove organic contaminants in water.
关键词： RGO,Adsorption,synergistic effect,BiVO4,Cu2O,Tetracycline
更新于2025-09-23 15:22:29
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Influence of surfactant on the synthesis of BiOCl/WO3 microcomposites for enhanced adsorption in aqueous solutions
摘要： BiOCl/WO3 microcomposites were synthesized using a one-step hydrothermal route in the presence of a variety of surfactants: polyvinylpyrrolidone (PVP), triethylene glycol (TEG), and Triton X-100 (TX-100). The as-synthesized microcomposites were exploited as efficient adsorbents for removing organic dyes (rhodamine B and methylene blue). Prior to adsorption studies, the structural, functional, and morphological characteristics of these adsorbents were studied using analytical techniques, including XRD, FE-SEM, TEM, and UV-DRS, which revealed the presence of large surface areas. The experimental results show that the PVP-synthesized BiOCl/WO3 microcomposite was significantly more effective as an adsorbent than the microcomposites synthesized using TEG or TX-100. This enhanced adsorption performance is attributable to the larger surface area associated with the developed microstructure of the PVP-stabilized BiOCl/WO3 microcomposite. The BiOCl/WO3 microcomposite synthesized from PVP was subjected to parametric studies involving catalyst dosage, pH, and initial dye concentration. The experimental data were fitted to isotherm models, and the mechanism of adsorption was investigated.
关键词： Rhodamine B,Methylene Blue,BiOCl/WO3 Composite,Adsorption,Surfactant
更新于2025-09-23 15:22:29
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Dispersion of Ag–AgBr particles in activated carbon as a recyclable photocatalyst for adsorption and degradation of pollutants
摘要： The photocatalyst, with high photocatalytic performance and cycling stability in visible light, as well as superior adsorption capability, was highly desired for degradation of organic pollutants in wastewater. In this contribution, the uniform and well-dispersed morphology with cubic Ag–AgBr particles were homogeneously decorated on the porous activated carbon (AC), by a simple solvothermal-photoreduction method, so as to obtain a hybrid photocatalyst with optimized nanostructure. The materials were systematically characterized and further evaluated for degradation of Rhodamine B (RhB) under visible light irradiation. The results indicated that the composite had a high adsorption capacity and photocatalytic properties for the removal of organic compounds, which is attributable to the formation of heterojunctions between Ag0, AgBr and AC. Furthermore, the possible photodegradation mechanism was postulated based on the photoactive radicals test. This study provides new insights into the design and fabrication of advanced visible light photocatalytic materials as well as the potential application in organic pollution cleanup.
关键词： adsorption,photocatalytic properties,Ag–AgBr-AC,photoactive radicals
更新于2025-09-23 15:22:29
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The Synthesis of Mesoporous Sio2/Tio2 Composite Particles by Sol-Gel Method and Effect of Hexane on its Structural Properties
摘要： Due to their unique properties such as high surface area, uniform and adjustable pore structure, and permeability of various molecules within and on their surface, mesoporous materials have become of interest in various fields including electronics, separation, catalysis, medical applications such as implant coatings and drug delivery. Mesoporous SiO2/TiO2 particles were synthesized by sol-gel method using various amounts of surfactant cetyl tri methyl ammonium bromide (CTAB) as structure directing agent under acidic condition; moreover, hexane was applied as a swelling agent. The samples were investigated using XRD, SEM, FTIR, SEM and N2 adsorption-desorption analyses, in addition, the incremental effect of surfactant and hexane were examined. The results obtained from the analysis clarified that an increase in amount of surfactant will lead to an increase in surface area, pore size and pore volume. Additionally, with adding hexane to the constant amount of surfactant; the results showed an increase in surface area, pore size and pore volume while order of the structure was maintained.
关键词： Mesoporous,Swelling agent,N2 adsorption-desorption,Surfactant
更新于2025-09-23 15:22:29
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Exfoliation of graphite as flexible SERS substrate with high dye adsorption capacity for Rhodamine 6G
摘要： Adsorption is one of the most important processes in wastewater treatment, especially for dye removal. In addition to adsorption, there must be a vigilant technique, such as Surface Enhanced Raman spectroscopy (SERS), for detection of low concentration of dye molecules to detect water foiling. Herein, we report a simple, low cost, rapid and e?cient technique for the production of exfoliated graphite (EG) under microwave irradiation at 800 W in 1 min, as excellent adsorption material for Rhodamine 6G (R6G) dye. The e?ect of adsorption process parameters such as pH, contact time, isotherm models (Langmuir and Freundlich) and kinetic models (pseudo-?rst and pseudo-second-order) on dye removal under aqueous solutions, were investigated. The maximum adsorption capacity for R6G dye is 212.72 ( ± 5.3) mg/g. Meanwhile compressing of EG, into a ?exible graphite sheet (FGS) demonstrates responsive SERS for R6G molecules up to detection limit of 10?7 mol/L. However, with silver nanoparticle incorporation, the detection limit increases up to 10?12 mol/L. Performance of ?exible sheet checked over a month by rubbing sheet through paper and cloth doesn’t have any impact on the synthesis of exfoliated graphite. Aging factor of the sheet also shows reproducible SERS spectra after a month. These are the highest reported values till today, for adsorption of R6G dye on Exfoliated graphite, with reasonable SERS detection.
关键词： Microwave irradiation,Flexible graphite sheet,Exfoliated graphite,SERS,Adsorption
更新于2025-09-23 15:22:29
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Wastewater treatment using a hybrid system combining adsorption, photocatalytic degradation and membrane filtration processes
摘要： In the present study, Chooka’s Wastewater treatment was investigated using di?erent combinations of adsorption, photocatalytic degradation, and membrane ?ltration process. Polymeric membranes were fabricated using wet phase inversion method employing polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and dimethylformamide (DMF) as a polymer matrix, hydrophilic additive, and solvent, respectively. Activated carbon and TiO2 nanoparticles were selected as an adsorbent and photocatalyst, respectively. TiO2 nanoparticles were synthesized using the sol-gel method and activated carbon was purchased from Merck Company. Liquid-liquid displacement (LLDP), scanning electron microscope (SEM) and contact angle tests were implemented to characterize the fabricated membranes. FT-IR and XRD analysis were also used for TiO2 nanoparticles characterization. The wastewater of Iran pulp and paper factory (Chooka) was used as the feed in separation processes. In hybrid separation systems, 6 di?erent con?gurations were considered and wastewater compositions were measured to determine the e?ectiveness of the utilized processes before and after treatment. Accordingly, the mean pore size of the fabricated PAN/PVP (16%/3%) membrane obtained from LLDP analysis was 9.72 nm. SEM results also indicated thicker active layer for the PAN/PVP membrane than that of the neat PAN membrane. According to the results of the contact angle tests, with the increasing of PVP content in the polymer matrix, the hydrophilicity of membranes improved. It was also found that membrane ?ltration had the best performance among single stage processes and the best separation performance was achieved when photocatalytic degradation, adsorption, and membrane ?ltration were used in series, respectively.
关键词： Photocatalytic degradation,Membrane ?ltration,Adsorption,Hybrid process,Wastewater treatment
更新于2025-09-23 15:22:29
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The Transitional Transmittance Response of ZIF-8 Gas Adsorption Observed Using Terahertz Waves
摘要： In this study, we recorded the transitional response in terms of terahertz transmittance of zeolitic imidazole framework-8 [Zn(2-methylimidazolate)2, ZIF-8] at 2.0 THz as a function of exposure time to gaseous propane and n-butane. The transmittance at 2.0 THz increased as gas adsorbed onto the ZIF-8. Conversely, during a nitrogen purge, transmittance decreased as the alkane gas desorbed. We estimated time constants for the adsorption and desorption of the two gases by comparing the plots of their responses. We also demonstrated the potential of using a combination of ZIF materials and terahertz technology as a novel gas analyzer.
关键词： Adsorption kinetics,Terahertz vibration,Metal-organic frameworks,Porous solids,Infrared absorption spectroscopy
更新于2025-09-23 15:22:29
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Cs adsorption on Bi2Se3
摘要： Bi2Se3 is a topological insulator whose unique properties result from topological surface states (TSS) in the band gap. The adsorption of Cs onto a Bi2Se3 surface is investigated by low energy ion scattering and work function measurements. Much of the deposited Cs quickly diffuses to the step edges forming one-dimensional chains of positively charged adatoms, along with some deposition on the terraces. The work function decreases until a coverage of 0.1 ML is reached, beyond which it increases slightly. The minimum in the work function is due to depolarization of the dipoles induced when the concentration of adatoms in the chains reaches a critical value. A slow diffusion of adsorbed Cs from the terraces to the step edges is also marked by changes in the neutralization of scattered Na+ and work function over time. The spatial distribution of the conductive charges in the TSS, which are primarily positioned between the first and second atomic layers, is confirmed by comparison of the neutralization of Na+ scattered from Bi and Se.
关键词： Topological insulators,Alkali adsorption,Work function,Low energy ion scattering
更新于2025-09-23 15:22:29
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Adsorption Dynamics of Redox Active Species onto Polarized Surfaces of Sensitized NiO
摘要： Mesoporous NiO films were deposited by means of a screen printing technique onto fluorine-doped tin oxide transparent electrodes and consequently sensitized with Erythrosin B (EryB) dye. The obtained colored NiO material was used as a working electrode in a three-electrode cell to study the evolution of the triple semiconductor/dye/electrolyte interface upon electrochemical polarization in dark conditions. The electrolyte was a solution of I3?/I? in acetonitrile, with the redox couple representing the typical redox shuttle of dye-sensitized solar cells (DSCs). The adopted electrochemical conditions were devised in order to simulate the actual electrical environment of the NiO/dye photocathode in a light-soaked DSC. The use of a benchmark sensitizer EryB and of the most widely used redox mediator I3?/I? is particularly meaningful for the study of the adsorption dynamics and the determination of possible degradative phenomena on the basis of the behavior of numerous analogue systems. Therefore, for the first time, the evolution of the NiO/EryB/I3?/I? multiple interface was investigated combining the electrochemical characterization with ex situ spectroscopic analysis by means of X-ray photoelectron spectroscopy. The resulting picture shows that EryB in the immobilized state promotes the redox processes based on the I3?/I? couple. Moreover, the EryB sensitizer inhibits the phenomena of recombination between the metal oxide semiconductor and the redox couple.
关键词： X-ray photoelectron spectroscopy,Sensitized NiO,Dye-sensitized solar cells,Redox active species,Adsorption dynamics,Polarized surfaces
更新于2025-09-23 15:22:29