Browsing by Author "Kucuk, M. M."

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The Liquefaction of Heracleum Persicum by Supercritical Fluid Extraction
(Taylor & Francis inc, 2013) Aysu, T.; Kucuk, M. M.
Milled Heracleum persicum stalk was converted to liquid products by using organic solvents (methanol, ethanol, acetone, and 2-butanol) with catalysts (10% NaOH or Na2CO3) and without catalyst in an autoclave at temperatures of 518, 538, and 558 K. The liquid products were extracted by liquid-liquid extraction (benzene and diethyl ether). The percentage yields from supercritical methanol, ethanol, 2-butanol, and acetone conversions were 49.1, 55.7, 58.7, and 71.0 at 558 K, respectively. In the catalytic run with NaOH, the highest conversion was obtained by using ethanol as a solvent at the same temperature. The yields of conversion were analyzed by GC-MS.
Removal of Crystal Violet and Methylene Blue From Aqueous Solutions by Activated Carbon Prepared From Ferula Orientalis
(Springer, 2015) Aysu, T.; Kucuk, M. M.
Ferula orientalis L. stalks were used as an agricultural solid biomass waste for preparation of activated carbon with zinc chloride activation using slow pyrolysis in a fixed-bed reactor. The chemical characteristics of the activated carbon obtained at 550 A degrees C were identified by elemental, fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, scanning electron microscopy analyses and found to have a surface area of 1,476 m(2)/g. The ability of the activated carbon to adsorb methylene blue and crystal violet from aqueous solutions has been investigated. Adsorption studies were performed at different initial dye concentrations (200-800 ppm), contact time (0.5-90 min) and temperature (25-45 A degrees C). Adsorption data were modeled with Langmuir, Freundlich and Temkin adsorption isotherms. Equilibrium data of the adsorption processes showed that adsorption of methylene blue is fitted to the Langmuir and crystal violet to the Freundlich isotherm. Pseudo-first-order, pseudo-second-order and Elovich kinetic models were used to analyze the kinetic data obtained at different initial dye concentrations. The adsorption kinetic data were very well described by the pseudo-second-order model. The calculated thermodynamic parameters such as change in free energy, enthalpy and entropy showed that adsorptions of both dyes onto activated carbon were spontaneous and endothermic under the experimental conditions.
Supercritical Fluid Extraction of Cotton Stalks
(Taylor & Francis inc, 2010) Sener, Ue.; Genel, Y.; Saka, C.; Kilicel, F.; Kucuk, M. M.
Cotton stalks mill were converted to liquid products by using organic solvents (methanol, 1-butanol, and 2-butanol) with catalysts (5 or 10% borax or ulexite) and without catalyst in an autoclave at temperatures of 540, 560, and 580 K. The liquid products were extracted by liquid-liquid extraction (benzene and diethyl ether) . The yields from supercritical methanol (10% borax) , 1-butanol (10% borax) , and 2-b butanol (10% borax) conversions were 54.1, 66.8, and 28.0 (at 580 K) , respectively. In the noncatalytic run with methanol was 37.4 at the same temperature.