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    Design and optimization of production parameters for boric acid crystals with the crystallization process in an MSMPR crystallizer using FBRM® and PVM® technologies
    (Elsevier Science Bv, 2017) Kutluay, Sinan; Sahin, Omer; Ceyhan, A. Abdullah; Izgi, M. Sait
    In crystallization studies, newly developed technologies, such as Focused Beam Reflectance Measurement (FBRM) and Particle Vision and Measurement (PVM) are applied for determining on-line monitoring of a representation of the Chord Length Distribution (CLD) and observe the photographs of crystals respectively; moreover recently they are widely used. Properly installed, the FBRM ensures on-line determination of the CLD, which is statistically associated to the Crystal Size Distribution (CSD). In industrial crystallization, CSD and mean crystal size as well as external habit and internal structure are important characteristics for further use of the crystals. In this paper, the effect of residence time, stirring speed, feeding rate, supersaturation level and the polyelectrolytes such as anionic polyacrylamide (APAM) and non-ionic polyacrylamide (NPAM) on the CLD as well as the shape of boric acid crystals were investigated by using the FBRM G600 and the PVM V819 probes respectively in an MSMPR (Mixed Suspension Mixed Product Removal) crystallizer. The CSD and kinetic data were determined experimentally using continuous MSMPR crystallizer running at steady state. The population density of nuclei, the nucleation rate and the growth rate were determined from the experimental population balance distribution when the steady state was reached. (C) 2017 Published by Elsevier B.V.
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    High hydrogen production rate from potassium borohydride hydrolysis with an efficient catalyst: CNT@Ru(0)
    (Desalination Publ, 2022) Keskin, M. Salih; Agirtas, Mehmet Salih; Baytar, Orhan; Izgi, M. Sait; Sahin, Omer; Horoz, Sabit
    We describe the production and catalytic activity of a carbon nanotube supported-Ru(0) (CNT@Ru(0)) catalyst. For the first time, the produced CNT@Ru(0) catalyst is used to achieve the greatest hydrogen production rate from potassium borohydride (KBH4) hydrolysis. The produced CNT@ Ru(0) catalyst shows promise in the creation of hydrogen from the degradation of KBH4. The hydrogen generation rate of CNT@Ru(0) is determined to be 86,264.85 mL min(-1) can with a low activation energy of 30.18 kJ mol(-1). CNTs are potential support for distributing metal catalysts, according to the current work. Furthermore, structural, morphological, and elemental characteristics of the produced CNT@Ru(0) catalyst are investigated.
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    Hydrogen production from NaBH4 using Co-Cu-B catalysts prepared in methanol: Effect of plasma treatment
    (Pergamon-Elsevier Science Ltd, 2016) Izgi, M. Sait; Sahin, Omer; Saka, Cafer
    In this work, methanol is used as an alternative to water. Preparation and characterization of Co-Cu-B catalysts in methanol for hydrogen generation from catalytic hydrolysis of sodium borohydride are studied. In addition, the plasma treated Co-Cu-B catalyst prepared in methanol for the hydrogen generation from catalytic hydrolysis of sodium borohydride is investigated. Process parameters including plasma gases, plasma time, NaOH and sodium borohydride concentrations and reaction temperature affecting the hydrolysis reaction of sodium borohydride in the presence of plasma treated Co-Cu-B catalysts are investigated. The maximum hydrogen generation rates of Co-Cu-B catalysts in water and methanol toward sodium borohydride hydrolysis are 734.4 and 3998 mL/g/min, respectively. Cold plasma treated Co-Cu-B catalyst for sodium borohydride hydrolysis is exhibited a hydrogen generation rate of about 4972 mL/g/min. The activation energy of the catalytic hydrolysis reaction of sodium borohydride with the plasma treated Co-Cu-B catalyst for first-order of is found at 17.38 kJ/mol. Copyright (c) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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    Influence of the using of methanol instead of water in the preparation of Co-B-TiO2 catalyst for hydrogen production by NaBH4 hydrolysis and plasma treatment effect on the Co-B-TiO2 catalyst
    (Pergamon-Elsevier Science Ltd, 2016) Sahin, Omer; Izgi, M. Sait; Onat, Erhan; Saka, Cafer
    In this work, methanol was used as an alternative to water. Our objective is to study the influence of the using of methanol instead of water in the preparation of Co-B-TiO2 catalyst. It is also expected to improve the activity of Co-B-TiO2 catalyst by plasma treatment for the hydrogen generation from hydrolysis of NaBH4. The prepared catalysts were characterized using BET (N-2 adsorption), SEM (scanning electron microscopy), XRD (X-ray diffraction) and FTIR (Fourier transform infrared) methods. The Co-B-TiO2 catalyst prepared in methanol shows maximum hydrogen generation rate, which is about 3.0 times higher than that obtained for Co-B-TiO2 catalyst prepared in water. The maximum hydrogen generation rates for the Co-B-TiO2 catalysts prepared in water and methanol were 1017 and 3031 mL/min/g, respectively. In addition, the maximum hydrogen generation rates for the plasma treated Co-B-TiO2 catalysts prepared in water and methanol were 1320 and 2656 mL/min/g, respectively. The activation energies of nth-order reaction model for the hydrogen production from hydrolysis of NaBH4 with the plasma treated Co-B/TiO2 catalyst prepared in methanol and Co-B/TiO2 catalyst prepared in methanol can be obtained from the slope and intercept of the regression line, being 41.29 and 36.24 kJ/mol, respectively. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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    Optimizing hydrogen production from alkali hydrides using supported metal catalysts
    (Springer Heidelberg, 2023) Karabulut, Abdurrahman; Izgi, M. Sait; Demir, Halil; Sahin, Oemer; Horoz, Sabit
    The present study aimed to investigate the effect of different parameters on the hydrogen production rate (HPR) during KBH4 hydrolysis using Co-B (pure) and Co-B@GO (supported) catalysts. The results showed that the HPR value for Co-B@GO catalyst was 2299.81 mL*gcat-1 min-1, which was approximately 2.3 times higher than that of the Co-B catalyst (1012.71 mLgcat-1 *min-1). The activation energy of Co-B@GO was also calculated to be 21.62 kJ/mol, lower than some reported values in the literature. This demonstrates the potential of Co-B@GO as a cost-effective and efficient catalyst for hydrogen production from alkali hydrides. The results of this study provide novel insights into the optimization of hydrogen production processes using supported metal catalysts.
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    Utilization of In Situ FBRM and PVM Probes to Analyze the Influences of Monopropylene Glycol and Oleic Acid as Novel Additives on the Properties of Boric Acid Crystals
    (Amer Chemical Soc, 2020) Kutluay, Sinan; Ceyhan, A. Abdullah; Sahin, Omer; Izgi, M. Sait
    The aim of this study was to determine the influences of monopropylene glycol (MPG) and oleic acid (OA) as novel additives on the chord length distribution (CLD) and modification of the shape of boric acid crystals in real time with the use of in situ focused beam reflectance measurement (FBRM) and particle vision and measurement (PVM) probes, which were positioned on a continuous mixed-suspension mixed-product removal (CMSMPR) crystallizer at a steady-state value. In this context, the FBRM probe was used to monitor CLD, which is expressed as the cumulative undersize square-weight percentage distribution of boric acid crystals. CLD is statistically proportional to crystal size distribution. The shapes of the boric acid crystals were viewed in real time with an in situ PVM probe. In addition, a scanning electron microscope (SEM) and an optical microscope were used to characterize the shapes of the boric acid crystals produced in the CMSMPR crystallizer. The chemical structures of the boric acid crystals were characterized by Fourier transform infrared (FT-IR) analysis. The population density of the nuclei, the nucleation rate, and the growth rate of the boric acid crystals were also calculated. As a result, it was proved that industrial problems encountered in the production of boric acid crystals by the crystallization process were eliminated especially in the presence of 100 ppm OA and 50 ppm MPG additives by FBRM, PVM, SEM analysis, and number density theory application. This study revealed novel insights into the modification of the shape of boric acid crystals and into the control of CLD in the presence of OA and MPG using in situ FBRM and PVM probes.