Browsing by Author "Genel, Ilyas"

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Effect of Process Parameters on Supercritical Liquefaction of Xanthium Strumarium for Bio-Oil Production
(Elsevier, 2016) Genel, Yasar; Durak, Halil; Aysu, Tevfik; Genel, Ilyas
Supercritical liquefaction process is used for producing energy from biomass. The common reaction conditions for supercritical liquefaction process are the 240-380 degrees C temperature range and 5-20 MPa pressure values range. Xanthium strumarium liquefaction experiments were performed in a cylindrical reactor (75 mL) in organic solvents (acetone, ethanol, methanol) under supercritical conditions with (zinc oxide, calcium hydroxide) and without catalyst at the temperatures of 250, 275 and 300 degrees C. The produced liquids at 300 degrees C in liquefaction were analyzed and characterized by Elemental, GC-MS and FT-IR. 36, 37 and 50 different types of compounds were identified by GC-MS obtained in acetone, ethanol and methanol respectively. The liquid product efficiency has been obtained at 300 degrees C in acetone with zinc oxide catalyst (74.80%). The highest HHV value has been calculated as 32.16 MJ/kg with calcium hydroxide catalyst in acetone. (C) 2016 Elsevier B.V. All rights reserved.
Facile Oxygen-Enriched Hierarchical Porous Carbon Particles Based on Biomass Wastes for Improving the Adsorption of Malachite Green From Aqueous Solutions
(Elsevier, 2025) Genel, Yasar; Genel, Ilyas; Saka, Cafer
The abundance of active groups and the surface areas of adsorbents used for the removal of contaminants such as dyes are very important for the effective adsorption process. For this purpose, the high surface area-activated carbon was obtained by activation of agricultural waste chestnut shells as carbon precursor(CSAC) with sodium hydroxide in the first stage of this study. In the second stage, the doping of oxygen atoms with nitric acid was carried out to further improve the surface properties of this activated carbon (O-doped CSAC). The obtained oxygen-rich activated carbon sample was used as an adsorbent to remove a cationic dye malachite green (MG). EDS, SEM, XRD, FTIR and nitrogen adsorption analyses were used for the characterisation of these activated carbon samples. FTIR, elemental analysis and EDS analyses showed a significant increase in the amount of oxygen groups on the surface. The BET surface area obtained for CSAC had a high surface area of 1548 m(2)/g. Kinetic, thermodynamic and isotherm parameters for the adsorption of MG with O-doped CSAC were determined. The qe values obtained for MG adsorption with O-doped CSAC showed an adsorption efficiency of about 90 %. An adsorption capacity of 284.6 mg g(-1) was obtained at 298 K with the Langmuir isotherm. The adsorption mechanism of MG with O-doped CSAC was also investigated.
Facile Preparation of Sulfonated Carbon Particles With Pomegranate Peels as Adsorbent for Enhanced Methylene Blue Adsorption From Aqueous Solutions
(Springer Heidelberg, 2024) Genel, Yasar; Genel, Ilyas; Saka, Cafer
In this study, in the first stage, activated carbon (AC) is produced from pomegranate peels, which are commonly found in Turkey, by pyrolysis after impregnation with NaOH (PPAC). In the second stage, the surface properties of the obtained PPAC sample are further improved by the sulfonation modification process with sulphuric acid (PPAC-S) for selective MB adsorption. For the characterization of the obtained samples, XRD, FTIR, SEM, nitrogen adsorption/desorption and EDS analyses were performed. Additionally, the zero charge points (pHzpc) of these samples were also determined. The isotherm, kinetic, and thermodynamic properties of the MB adsorption process with PPAC-S were examined. The qe values obtained for MB adsorption with PPAC and PPAC-S samples were found to be 98.79 mg/g and 199.18 mg/g, respectively. There is an increase of 100% in MB adsorption with the sulfonated PPAC adsorbent. Maximum adsorption capacity values of MB with the Langmuir model at temperatures of 298, 308, and 318 degrees C were 212.7, 216.9, and 245.1 mg/g, respectively. Additionally, the mechanism of MB adsorption onto PPAC-S was also attempted to be elucidated.
Facile Synthesis of Mesoporous Activated Carbons Based on Ash Tree for Methylene Blue Adsorption: Mechanism, Kinetics, Isotherm, and Thermodynamic Studies
(Taylor & Francis inc, 2023) Genel, Yasar; Genel, Ilyas; Saka, Cafer
Activated carbons(AC) were synthesized as a result of chemical activation with ZnCl2, NaOH, H3PO4, and H3BO3 from the ash tree(AH), which is abundant in Turkey and the world. It was investigated that the obtained ACs could be used as effective adsorbents for the removal of methylene blue(MB) from the aqueous solution. SEM, EDX, BET, FTIR, and CHNS elemental analyses were used for the characterization of raw and ACs. The results show that carbonaceous materials contain both mesoporous and active functional groups. The maximum adsorption capacities obtained as a result of chemical activation of ZnCl2 (AH-ZnCl2) and NaOH (AH-NaOH) with the best surface area values were determined as 334 mg g(-1) and 364 mg g(-1), respectively. The adsorption mechanism was evaluated with pseudo-first-order and pseudo-second-order kinetic models. It can be concluded that ACs prepared from ash wood are quite ideal when compared with different adsorbents in the literature for removing methylene blue from aqueous solutions.
Hydrogen Production and Electrochemical Energy Storage With a Dual-Function Application of Boron and Oxygen-Doped Biomass-Based Porous Activated Carbon-Based Composite Material
(Pergamon-elsevier Science Ltd, 2025) Yardim, Yavuz; Genel, Ilyas; Saka, Cafer
In this study, boron (B) and oxygen (O) atoms were doped into activated carbon (AC) derived from pomegranate peel biowaste through potassium hydroxide (KOH) activation using boric acid. This material (B, O doped ACPP) is used both as a metal-free catalyst in the production of hydrogen (H-2-P) with sodium borohydride (NaBH4) in methanol (CH3OH) and as an electrode for a supercapacitor in the energy storage field. The results provide significant increases in both application areas with the same material. The TEM analysis revealed the formation of uniformly distributed nanoscale particles (similar to 8.25 nm), which further increases the accessible surface area and shortens ion diffusion paths. The completion time of H-2 release by NaBH4 reaction in only CH3OH is 16 min. However, the H-2-P reaction of NaBH4 in CH3OH with B, O doped ACPP is completed in 7 min. H-2 production rate (HGR) value obtained using B, O doped ACPP with 0.25 g NaBH4 is 18471 mLmin(-1)g(cat)(-1). A substantial enhancement of approximately 2.5 times in specific capacitance is observed for B, O-doped ACPP compared to ACPP. At a current density of 1.6 A g(-1), the B, O-doped ACPP-GCE electrode demonstrates excellent cycling stability, 87.8 % of its capacitance after 10.000 cycles. The charge transfer resistance (Rct) values were measured to be 41.1 Omega for ACPP and 17.7 Omega for B, O doped ACPP.
Utilisation of Green Nitrogen-Doped Biomass-Based Hierarchical Porous Activated Carbon Particles for Enhancement of Electrochemical Energy Storage Performance
(Elsevier Science Sa, 2025) Genel, Ilyas; Yardim, Yavuz; Saka, Cafer
Activated carbon particles were obtained from rosehip wood-based carbon precursor by chemical activation with potassium hydroxide (RHAC). After this pyrolysis process, nitrogen-doped hierarchical porous carbon was prepared by ammonia activation (N-doped RHAC). The prepared carbonaceous materials were designed as an electrode for a supercapacitor. Standard electrochemical analyses were performed. The specific capacitance (Cs) of RHAC/GCE was determined to be 25 F/g at 2.5 mV/s and 23 F/g at 0.2 A/g. In contrast, the N-doped RHAC/ GCE demonstrated significantly higher Cs values of 119 F/g at 2.5 mV/s and 121 F/g at 0.2 A/g. According to CV and GCD measurements, the N-doped RHAC material exhibited approximately a fivefold increase in specific capacitance compared to the RHAC-based electrode. A specific capacitance retention rate of 94.6 % was obtained after 1000 cycles at a current density of 1.6 A/g. The surface properties and characteristics of the obtained materials were carried out by SEM, nitrogen adsorption, Raman, FTIR, EDS and XPS analyses. EDS and XPS analyses showed that N atom doping was successful. This study suggests that rosehip tree biomass-based N atom doped carbon material is suitable for supercapacitors as an electrode.