Carlos A. Ray-Mafull; Dachamir Hotza; Raquel García-Gallardo; Orlando F. Cruz Junior; Jarosław Serafin
Abstract
In this study, the adsorption and thermodynamic parameters of Diazepam drugs adsorbed onto six activated carbons were determined. A simulated gastric fluid was applied at pH 1.2 for 4 h. The samples were characterized by FTIR, N2 isotherm at 77 K, and CO2 at 273 K. The experimental adsorption was fitted ...
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In this study, the adsorption and thermodynamic parameters of Diazepam drugs adsorbed onto six activated carbons were determined. A simulated gastric fluid was applied at pH 1.2 for 4 h. The samples were characterized by FTIR, N2 isotherm at 77 K, and CO2 at 273 K. The experimental adsorption was fitted by isotherm models: Langmuir Type I and II, DR, Halsey, Freundlich, Harkins-Jura, Temkin, and BET. UV visible spectra monitored residual drugs. The results showed relationships between temperature increase, adsorbent characteristics, and the behavior of these drugs in acid solution. The positive values of all the isosteric adsorption enthalpies determined from the slope Van’t Hoff plot (R 2 >97) indicated the endothermic nature of the adsorption process. In all cases, ΔG<0 so that the spontaneous character of the adsorption process was attested. Moreover, the positive values of ΔS stated that the randomness increased at the solid-solution interface during the adsorption process.
Misael D. Cogollo Valdes; Magda A. Salazar Vega; Melissa J. Cely Pinto; Ana M. Pinilla Torres; Jessica V. Ardila Antolínez; Marisol Fernández Rojas; Luz A. Carreño Diaz*
Abstract
Environmental consequences of high consumption of fossil fuels containing sulfur compounds have promoted research in technologies for their removal. Catalytic hydrodesulphurization currently used requires high temperature and pressure. Alternative technologies based on ionic liquids pure and anchored ...
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Environmental consequences of high consumption of fossil fuels containing sulfur compounds have promoted research in technologies for their removal. Catalytic hydrodesulphurization currently used requires high temperature and pressure. Alternative technologies based on ionic liquids pure and anchored to matrices have shown good desulfurization properties. Composites offer advantages of reuse, less time consuming and costs, using lower IL amount. In this work, we obtained a solid composite containing [BMIM][BF4] supported on oxidized active carbon and characterized by FTIR, BET, TGA-DSC, and SEM. We evaluated the extraction capacity of benzothiophene, thiophene, dibenzothiophene, and diphenyl sulphide from a model fuel with both pure [BMIM][BF4] as well as the same IL on oxidized activated carbon. In the extraction process using pure IL were achieved removal percentages of up to 69.8% whereas with the composite it was possible to reduce 80 % of the sulfur content.
Chee-Heong Ooi; Akane Ito; Tsubasa Otake; Fei-Yee Yeoh
Abstract
Palm kernel shell (PKS) was utilized as a precursor for the preparation of activated carbon (AC) via different carbonization temperatures and carbon dioxide gas activation processes. The physical and chemical properties of the AC samples were studied by TGA, nitrogen adsorption analysis and SEM. The ...
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Palm kernel shell (PKS) was utilized as a precursor for the preparation of activated carbon (AC) via different carbonization temperatures and carbon dioxide gas activation processes. The physical and chemical properties of the AC samples were studied by TGA, nitrogen adsorption analysis and SEM. The results show that the AC sample with BET surface area up to 622 m 2 g -1 and total pore volume of 0.297 cm 3 g -1 with narrow pore size of 1.2 nm were obtained. The SEM shows that more pores were revealed on the surface of AC after the carbonization and activation processes. The AC samples carbonized at 500 and 600 °C (CA-500 and CA-600) exhibited higher Ce removal percentage (99.94 %) than that of the other samples. Higher BET surface area of the CA-500 and CA-600 samples resulted in slightly more Ce ions to be adsorbed and precipitated compared to that of other samples. The result indicates that high pH value and BET surface area of AC sample has a rather strong influence on Ce removal. AC samples show excellent Ce removal capacity, thereby; the results suggest that the PKS-based AC could be a promising adsorbent for the cerium removal application.
Atikah Ali; Rubia Idris
Abstract
In this study, the low-cost activated carbon from pistachio shell waste was sought through experiments using rapid synthesis of microwave-induced pyrolysis. The effect parameters of activating agents and microwave power on the surface area and carbon yield were studied. The results revealed that, well-grown ...
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In this study, the low-cost activated carbon from pistachio shell waste was sought through experiments using rapid synthesis of microwave-induced pyrolysis. The effect parameters of activating agents and microwave power on the surface area and carbon yield were studied. The results revealed that, well-grown pore structures with the highest surface area (681.2 m 2 g -1 ) and the highest carbon yield (70.3%) were produced using K2CO3 as an activating agent and 600 W power level exposed to 15-minute irradiation. The activated carbon with the highest porosity (AC600) was subsequently utilized in the tungsten carbide (WC) preparation which employed a facile method of mechanical milling. Finally, a high-thermal treatment under inert conditions was performed to completely convert W into WC. The physicochemical properties of the catalyst were evaluated by N2 adsorption-desorption, XRD, FESEM and TEM. It was observed that, the tungsten carbide produced was small and uniform spherical nanoparticles with average diameters of 60 to 100 nm. High porosity and high surface area of catalyst support were identified as factors leading to a homogeneous distribution of metal catalyst. Therefore, the nanoparticles of WC produced were attributed to activated carbon with high porosity (AC600) due to well distribution of the tungsten crystal phase.
Heon Lee; Sun-Jae Kim; Kay-Hyeok An; Jung-Sik Kim; Byung-Hoon Kim; Sang-Chul Jung
Abstract
The ruthenium oxide/activated carbon composite (RCC) were synthesized using an innovative plasma-in-liquid process, which is known as liquid phase plasma (LPP) process. This technique uses a single-step process for the synthesis of metal nanoparticles on supporting materials. LPP process led to simultaneous ...
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The ruthenium oxide/activated carbon composite (RCC) were synthesized using an innovative plasma-in-liquid process, which is known as liquid phase plasma (LPP) process. This technique uses a single-step process for the synthesis of metal nanoparticles on supporting materials. LPP process led to simultaneous precipitation of ruthenium and ruthenium oxide nanoparticles on the surface of activated carbon, which is then oxidized to ruthenium oxide during the thermal oxidation process. The specific capacitances of RCC electrodes prepared through the LPP and oxidation process were higher than that of bare AC. The specific capacitance increased with increasing LPP process duration and oxidation treatment. The specific capacitance of ruthenium oxide/carbon composite increased with increasing LPP process duration. The ruthenium oxide/carbon composite prepared through the LPP process and thermal oxidation showed smaller resistances and larger initial resistance slopes than bare activated carbon powder and this effect was intensified by increasing the LPP process duration. The RCC electrodes showed smaller resistances and larger initial resistance slopes than bare AC and this effect was intensified by increasing the LPP process duration and oxidation treatment.
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