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    Design and optimization of production parameters for boric acid crystals with the crystallization process in an MSMPR crystallizer using FBRM (R) and PVM (R) 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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    Determination of Nucleation Kinetics of Ammonium Biborate Tetrahydrate
    (CHIMINFORM DATA S A, 2014) Sahin, Omer; Ozdemir, Mustafa; Izgp, M. Sait; Demir, Halil; Ceyhan, Ayhan Abdullah
    The ammonium biborate tetrahydrate was synthesized by stoichiometric incorporation of boric acid and ammonium hydroxide in aqueous solution and the effects of supersaturation, temperature, pH of solution, cooling rate and presence of impurities upon the metastable zone width (MZW) were investigated. The MZW of ammonium biborate tetrahydrate aqueous solution was increased with increasing concentration of impurities. The saturation temperature was increased in the presence of Ca (II) ion and decreased in the presence of Pb(II) and Mg (II) ions.
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    Effects of different temperatures and additives on the metastable zone width precipitation kinetics of NaBO2
    (MAIK NAUKA/INTERPERIODICA/SPRINGER, 2014) Kaya, Mustafa; Ceyhan, Ayhan Abdullah; Sahin, Omer
    In this study, the sodium metaborate, which is applicable in various industrial areas, and its metastable zone width that is very important for its production by crystallization, and its nucleation are investigated to obtain the necessary thermodynamic parameters. The polythermal and isothermal method has been used for the measurement of metastable zone width. Metastable zone width of NaBO2 has found at 9A degrees C at average and cooling rate do not have any effect on it. In addition, the effect of sodium metaborate on the hydrogen storage capacity of sodium borohyride solutions that is known as one of the best hydrogen sources today is investigated at the various concentrations of sodium borohyride in the medium. Results have shown that three different areas emerged as the percentage of NaBH4 in the solution increased.
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    A novel thermal process for activated carbon production from the vetch biomass with air at low temperature by two-stage procedure
    (ELSEVIER SCIENCE BV, 2013) Ceyhan, Ayhan Abdullah; Sahin, Omer; Saka, Cafer; Yalcin, Ali
    The method differs from a known method for the pyrolysis processing of agriculture waste. In this article, a novel thermal process of producing activated carbon from the vetch at low temperature by air is discussed. This paper reports the preparation of activated carbon with two-stage pyrolysis with air from the vetch by zinc chloride activation. The experiments in this study vary the pre- and post-treatment procedures, the impregnation ratio of the activating agent, and the carbonization temperature. The pyrolysis was carried out at different low activation temperatures in the range of 30-80 and 240-400 degrees C. Adsorption capacity was demonstrated with BET and iodine number. The respective highest BET surface area and iodine number for the produced activated carbons was obtained as 1287 m(2)/g and 1004 mg/g. SEM evaluated the structural morphology of activated carbons. The surface chemical characteristics of activated carbons were determined by FTIR spectroscopic method. The use of low temperature chemical carbonization has the potential to further improve the economics of generating activated carbon. (C) 2013 Elsevier B.V. All rights reserved.
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    Preparation of High Surface Area Activated Carbon from Elaeagnus angustifolia Seeds by Chemical Activation with ZnCl2 in One-Step Treatment and its Iodine Adsorption
    (TAYLOR & FRANCIS INC, 2015) Sahin, Omer; Saka, Cafer; Ceyhan, Ayhan Abdullah; Baytar, Orhan
    The present study was conducted with the preparation of activated carbon through one-step chemical activation using zinc chloride (ZnCl2) as the activating agent from Elaeagnus angustifolia seeds (EAS). The effect of impregnation ratio, activation temperature, and activation time on activated carbon surface area was discussed. The properties of activated carbon were characterized by N-2 adsorption (BET), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The best conditions for preparing activated carbon were identified to be temperature of 500 degrees C, impregnation ratio of 150%, impregnation time of 48 h, and activation time of 60 min with BET surface area of 1836 m(2)/g. The adsorption capacity was demonstrated by the iodine numbers.
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    The pyrolysis process of biomass by two-stage chemical activation with different methodology and iodine adsorption
    (TAYLOR & FRANCIS INC, 2016) Sahin, Omer; Saka, Cafer; Ceyhan, Ayhan Abdullah; Baytar, Orhan
    Current concerns with the high energy/cost nature of activated carbon production have encouraged research into alternative activated carbon production methods to reduce the environmental impact. The purpose of this study is to produce the activated carbon from biomass (carob bean seed husk, CBSH) by chemical activation with a different methodology using zinc chloride. Two different activation temperature methodologies for the preparation of activated carbons were applied at the ranges of 30-80 and 200-350 degrees C. The effects of the pre-activation and activation temperatures, duration time, and the impregnation ratio on the surface and chemical properties of activated carbon were investigated. Studies were conducted on the adsorption of iodine from the prepared activated carbon. The highest iodine adsorption number was achieved as 874 mg/g. Langmuir surface area was 1544 m(2)/g. The structural morphology of activated carbons was evaluated with a scanning electron microscope. The surface chemical characteristics of activated carbons were determined by the Fourier transform infrared (FTIR) spectroscopic method.