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Öğe A comprehensive new study on the removal of Pb (II) from aqueous solution by sirnak coal-derived char(Taylor & Francis Ltd, 2021) Batur, Ebru; Baytar, Orhan; Kutluay, Sinan; Horoz, Sabit; Sahin, OmerIn this study, char was prepared from the Sirnak coal derivative as a new adsorbent by the pyrolysis process and successfully applied for Pb (II) removal. Prepared char adsorbent was characterized by analysis techniques such as thermogravimetric (TG)/differential thermogravimetric (DTG), iodine number, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) surface area. In the experimental design of the Pb (II) removal process, the relationship between operating factors (contact time, initial Pb (II) concentration and temperature) and process responses (adsorption capacity and removal efficiency) was modelled by applying response surface methodology (RSM). After that, the operating factors for the maximum adsorption capacity and removal efficiency of Pb (II) by char were optimized. In the removal of Pb (II), pseudo-first order and pseudo-second order kinetic models were used to determine the process mechanism. In addition, adsorption isotherm models such as Langmuir, Freundlich, and Dubinin-Radushkevich were applied to the equilibrium data to explain the adsorption mechanism between the adsorbent and adsorbate molecules. According to the results obtained, it was determined that kinetic and equilibrium isotherm data were better defined with pseudo-second order kinetic and Dubinin-Radushkevich isotherm models, respectively. The optimum values of the contact time, initial Pb (II) concentration, and temperature for maximum adsorption capacity (124.64 mg/g) and removal efficiency (92.35%) of Pb (II) were found as 150.00 min, 144.81 ppm, and 35.06 degrees C, respectively. This study indicated the application potential of Sirnak coal-derived char as a promising cost-effective adsorbent for the removal of heavy metals.Öğe Adsorption kinetics, equilibrium and thermodynamics of gas-phase toluene onto char produced from almond shells(2019) Kutluay, Sinan; Baytar, Orhan; Şahin, ÖmerToluene is the primary material in chemical process industries and is often usedas a raw material in the production of many chemicals and as a solvent in manyengineering processes. In this study, the material of char, which is used as anadsorbent, was produced from almond shells. The adsorption process of gasphase toluene onto char was investigated using a laboratory-scale fixed-bedreactor under atmospheric pressure. The structure of the char was characterizedby BET and FTIR. The influences of adsorption parameters such as nitrogen (N2)flow rate as the gas-phase toluene carrier, char amount, gas-phase tolueneconcentration at the inlet and the adsorption temperature on both theadsorption capacity and adsorption efficiency were examined. It was found thatthe adsorption of the gas-phase toluene onto char could be well represented bythe pseudo-second-order kinetic model. Equilibrium isotherm data wereanalyzed by the Langmuir and Freundlich isotherm models and the resultsindicated that the adsorption process was described well by the Langmuirisotherm model. The maximum monolayer adsorption capacity (qmax) of the charwas determined as 15.42 mg g-1 for 303 K. Thermodynamic parameters such as?G° = -7.93 kJ mol-1, ?H°= -17.18 kJ mol-1, ?S°= -0.013 kJ mol-1 K-1 showed that theadsorption process was spontaneous, exothermic and physical. The resultsshowed that the material of char produced from almond shells could be used asa biosorbent to remove the material of gas-phase toluene from various industrialand natural sources through the adsorption method.Öğe Aktif karbon destekli ucuz ve kullanışlı katalizörün amonyak bor hidrolizinde incelenmesi(2023) Beştaş, Hatice; Onat, Erhan; Şahin, Ömer; Demirci, Sevilay; Baytar, Orhan; İzgi, Mehmet SaitBu çalışmada ilk kez kahve çekirdeği atığından (kahve telvesinden) elde edilen aktif karbon kullanılarak CuMoB@AC ilk kez katalizörü sentezlendi. Burada en iyi katalitik performanslarını belirlemek amacıyla; Cu:Mo oranı, Metal/AC oranı, optimum NaOH oranı, katalizör miktarı, en uygun NH 3 BH 3 oranı ve farklı sıcaklıklarda yapılan deneyler sonucunda da reaksiyon kinetiği çıkarılarak reaksiyonun derecesinin n. dereceden (0.9) olduğu ve aktivasyon enerjisinin de 34,89 kJ/mol olduğu belirlendi. Aynı zamanda katalizörümüz karakterizasyonu belirlemek için SEM-EDS, XRD ileri analitiksel yöntemler kullanılarak belirlenmiştir.Öğe Al2O3 supported co-cu-b ( Co-Cu-B/Al2O3) catalyst for hydrogen generatıon by hydrolysıs of aqueous sodıum borohydrıde (NaBH4) solutıons(2019-07-10) Baytar, Orhan; İzgi, M. Sait; Horoz, Sabit; Şahin, Ömer; Nar, SerenIn this study, Al2O3 supported Co-Cu-B (Co-Cu-B/Al2O3) catalyst was synthesized by chemical impregnation and precipitation method to be used for catalytic hydrogen generation from NaBH4. Co-Cu-B/Al2O3 catalyst was synthesized at various ratios using Co-Cu-B/Al2O3 (5-20%). The effect of some parameters such as NaOH concentration (0- 7%), NaBH4 concentration (2.5-7.5%), catalyst amount (25-150 mg) and solution ambient temperature was investigated on the catalytic hydrolysis of NaBH4. The hydrogen generation rate was found as 2519 and 8962 mL*g-1 *min-1 for Co-Cu-B and Co-CuB/Al2O3 catalysts in NaBH4 hydrolysis, respectively. The order rate kinetics and activation energy for Co-Cu-B/Al2O3 catalyst were determined as 0.125 and 27 kJ*mol-1 , respectively. The obtained results suggest that Co-Cu-B/Al2O3 catalysts can be used for mobile applications of PEMFC systems.Öğe Amonyum floroborat üretimi ve üretim parametrelerinin belirlenmesi(2020) Ceyhan, Ayhan Abdullah; Bağcı, Safiye; Baytar, Orhan; Şahin, ÖmerBu çalışmada, borik asit ve amonyum hidrojen florürün reaksiyonu ile amonyumfloroborat (NH4BF4) üretimine ait üretim parametreleri incelenmiştir. Bu amaçla,reaktif besleme oranı, reaksiyon sıcaklığı, karıştırma hızı, karıştırıcı cinsi, ikinciçözücü etkisi parametrelerinin etkileri ayrı ayrı belirlenmiştir. Reaksiyon sonucuelde edilen kristallerin yapısal analizleri ve yüzey morfolojileri ise sırasıylaXRD, FT-IR ve SEM analizleri yapılarak aydınlatılmaya çalışılmıştır. Amonyumfloroborat üretimi için en uygun reaksiyon şartları; reaktif besleme oranı, 1:2;reaksiyon sıcaklığı, 90 oC; karıştırıcı cinsi, sıcak hava şeklinde tespit edilmiştir.Limit oksijen indeksi analizleri, amonyum floroboratın mükemmel alev geciktiriciolduğunu göstermiştir.Öğe Bioeconomic transformation of bio-oil production wastes: a novel adsorbent material for toxic dye adsorption and optimization of process parameters(Taylor & Francis Ltd, 2024) Yildiz, Hakan; Dolas, Hacer; Baytar, Orhan; Sahin, OmerIn this study, for the first time, an adsorbent material was produced from the waste left behind after the bio-oil production process from Terebinth (Pistacia Terebinthus L.) seeds as part of bioconversion, and the adsorption of the hazardous dyestuff methylene blue from aquatic media was investigated. The characterization of the adsorbent was performed using FT-IR, SEM, and BET analysis. The characterization of methylene blue adsorption was conducted to fully understand its nature, including its kinetics, equilibrium, and thermodynamic works. The maximum adsorption capacity (qmax) of the monolayer, as determined from the equilibrium data, was calculated to be 166.07 mg g-1. Additionally, the experimental design method was utilized to determine the optimum conditions of the methylene blue adsorption process under various conditions. This study revealed that activated carbons from Terebinth seeds can be used as an economical and environmentally friendly adsorbent, which is very suitable for the removal of highly toxic dyes.Öğe Biogenic Synthesized Bare and Boron-Doped Copper Oxide Nanoparticles from Thymbra spicat ssp. spicata: In Silico and In Vitro Studies(Springer/Plenum Publishers, 2024) Cengiz, Mustafa; Baytar, Orhan; Sahin, Omer; Kutlu, Hatice Mehtap; Ayhanci, Adnan; Sezer, Canan Vejselova; Gur, BahriThe biosynthesis technique and biogenic copper oxide nanoparticles (CuONPs) are commonly used in a variety of applications including medicine. Bare (CuONPs) and boron-doped copper oxide nanoparticles (B/CuONPs) were produced via the green synthesis method using Thymbra spicat ssp. spicata due to their nontoxic, coast effective and facile properties. The nanoparticles were characterized by using X-ray diffraction, fourier transform infrared, UV-visible spectroscopy, transmission electron microscopy, and Scanning electron microscopy with Energy Dispersive X-ray spectroscopy analysis. The produced nanoparticles performed antibacterial activity against human pathogenic organisms of both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria by using the microdilution technique. B/CuONPs showed high activity on Gram-positive bacteria, while CuONPs showed high activity on Gram-negative bacteria. The cytotoxic effect synthesized CuONPs and B/CuONPs were evaluated against human hepatocarcinoma (HepG2) cells by using MTT, Annexin-V, Caspase-3/7, and confocal microscopic evaluations. Moreover, the in-silico results have shown for the first time that the active role in the Caspase-3/7 step of the triggered apoptosis pathway is due to the activity of Caspase-7. The results indicated that the biogenic CuONPs and B/CuONPs exerted potential anti-cancer and anti-bacterial activity on HepG2 and S. aureus and E. coli that imply to remarkable biological activity. The green synthesized nanoparticles have clearly proposed promising biogenic nanomaterials for biomedical treatments.Öğe Catalytic activity of cobalt-boron-fluoride particles with different solvent mediums on sodium borohydride hydrolysis for hydrogen generation(Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019) İzgi, Mehmet Sait; Şahin, Ömer; Baytar, Orhan; Saka, CaferCatalysts prepared in a different solvent medium have different activities because of its different acidity, basicity and viscosity properties. The synthesis mechanism of cobalt-boron-fluoride in water, propanol and ethanol solvents was evaluated. Characterization studies of cobalt-boron-fluoride catalyst were performed with Brunauer-Emmett-Teller surface area, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy- energy dispersive x-ray spectroscopy measurements. The effects of sodium borohydride (SB), and temperature on the SB hydrolysis reaction with the catalyst samples were studied. The maximum hydrogen generation rate (HGRs) of the cobalt-boron (ethanol solvent) and cobalt-boron-fluoride (ethanol solvent) catalysts were 1942 and 4533 mlmin−1g−1, respectively. The activation energy was 32.45 kJ mol−1.Öğe Catalytic effect of nickel oxide nanoparticles from Lupinus Albus extract on green synthesis and photocatalytic reduction of methylene blue: kinetics and mechanism(Taylor & Francis Inc, 2024) Yilmaz, Mine; Ceyhan, A. Abdullah; Baytar, OrhanGreen synthesis of nanomaterials is advancing due to their ease of synthesis, cheapness, nontoxicity, and renewability. An environmentally friendly biogenic method has been developed for the green synthesis of nickel oxide nanoparticles (NiO NPs) using phytochemical-rich bioextract. They are rich in bioextract phenolics, flavonoids, and berberine. These phytochemicals successfully reduce and stabilize NiNO3 into NiO NPs. In this study, NiO NPs were synthesized by the green synthesis method from Lupinus Albus. Characterization of NiO NPs was carried out by TEM, XRD, SEM, UV, XRF, BET, and EDX analyses. According to XRD analysis, TEM results also support this, where the NiO NPs particle size diameter is 5 nm. It was determined by the Tauc equation that the band energy gap of NiO NPs is 1.69 eV. It was determined that the BET surface area of NiO NPs was 49.6 m2/g. NiO nanoparticles synthesized from Lupinus Albus extract by the green synthesis method were used as catalysts in the photocatalytic reduction of methylene blue with NaBH4. In the photocatalytic reduction of methylene blue with NaBH4, it was determined that there was no color change in 48 h without a catalyst, and in the presence of NiO nanoparticle catalyst, methylene blue was reduced by 97% in 8 min. The kinetics of the photocatalytic reduction of methylene blue with NaBH4 is a pseudo-first-order kinetic model and the kinetic rate constant is determined as 0.66 min-1, indicating that the catalytic effect of NiO NPs is very high at this value. NiO NPs were used five times in the photocatalytic reduction of methylene blue with NaBH4 and it was determined that the reduction of methylene blue was over 90% in each use. NiO nanoparticles were synthesized from Lupinus Albus extract by green synthesis, which is an easily applied, cost-effective, and environmentally friendly method. The synthesized NiO nanoparticles were characterized using various characterization techniques. NiO nanoparticles have a high catalytic effect in the photocatalytic reduction of methylene blue with NaBH4. Photocatalytic reduction of methylene blue with uncatalyzed NaBH4 could not be achieved, and 97% reduction of methylene blue was completed in 8 min in the presence of NiO nanoparticle catalyst.Öğe CeO2 supported multimetallic nano materials as an efficient catalyst for hydrogen generation from the hydrolysis of NaBH4(Pergamon-Elsevier Science Ltd, 2020) Izgi, Mehmet Sait; Baytar, Orhan; Sahin, Omer; Kazici, Hilal CelikNowadays, there is still no suitable method to store large amounts of energy. Hydrogen can be stored physically in carbon nanotubes or chemically in the form of hydride. In this study, sodium borohydride (NaBH4) was used as the source of hydrogen. However, an inexpensive and useful catalyst (Co-Cr-B/CeO2) was synthesized using the NaBH4 reduction method and its property was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), x-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) measurements. The optimized Co-Cr-B/CeO2 catalyst exhibited an excellent hydrogen generation rate (9182 mLg(metal)(-1) min(-1)) and low activation energy (35.52 kJ mol(-1)). The strong catalytic performance of the Co-Cr-B/CeO2 catalyst is thought to be based on the synergistic effect between multimetallic nanoparticles and the effective charge transfer interactions between the metal and the support material. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Characterization of Microwave and Conventional Heating on the Pyrolysis of Pistachio Shells for the Adsorption of Methylene Blue and Iodine(Taylor & Francis Inc, 2018) Baytar, Orhan; Sahin, Omer; Saka, Cafer; Agrak, SelmanThe production of activated carbon was investigated using the sequential combination of microwave and conventional heating of pistachio shells as the raw precursor with zinc chloride. Several techniques such as thermogravimetric and differential thermal analyses, infrared spectroscopy, scanning electron microscopy, and specific surface area analyses were performed to characterize the samples. The highest specific surface area value for the activated carbon prepared at a microwave power of 200W with microwave time of 20min, and flow rate of 50mLmin(-1) was 1468m(2)g(-1). The methylene blue and iodine adsorption capacities were 331 and 1276mgg(-1), respectively. The results were compared to those obtained using physical and chemical activation methods and showed that the sequential combination of microwave and conventional heating reasonably influenced the micropore surface area of the samples as well as the specific surface area.Öğe Designing copper-doped zinc oxide nanoparticle by tobacco stem extract-mediated green synthesis for solar cell efficiency and photocatalytic degradation of methylene blue(Taylor & Francis Inc, 2024) Ekinci, Arzu; Sahin, Omer; Kutluay, Sinan; Horoz, Sabit; Canpolat, Gurbet; Cokyasa, Mine; Baytar, OrhanThis study presents the green synthesis of copper-doped zinc oxide (Cu-doped ZnO) nanoparticles using tobacco stem (TS) extract. The environmentally friendly synthesis method ensures distinct features, high efficiency, and applicability in various fields, particularly in solar cell technology and photocatalytic applications. ZnO nanostructures are investigated due to their unique properties, cost-effectiveness, and broad range of applications. The nanoparticles are synthesized with varying Cu concentrations, and their structural, morphological, and compositional characteristics are thoroughly analyzed. The Cu-doped ZnO nanoparticles exhibit improved properties, such as increased surface area and reduced particle size, attributed to the incorporation of Cu dopants. The green synthesis approach using TS extract serves as a stabilizing agent and avoids the toxicity associated with chemical methods. Characterization techniques including SEM, TEM, EDX, FTIR, and XRD confirm the successful synthesis of the nanoparticles. Photocatalytic degradation studies reveal that the 5% Cu-doped ZnO exhibits the highest photocatalytic activity against methylene blue, attributed to synergistic effects between Cu and ZnO, including oxygen vacancy and electron-hole pair recombination rate suppression. The photocatalytic mechanism involves the generation of superoxide and hydroxyl radicals, leading to methylene blue degradation. Furthermore, the Cu-doped ZnO nanoparticles demonstrate promising photovoltaic performance, with the optimal efficiency observed at a 5% Cu concentration. The study suggests that Cu-doped ZnO has the potential to enhance solar cell efficiency and could serve as an alternative material in solar cell applications. Future research should focus on refining Cu-doped ZnO for further improvements in solar energy conversion efficiency The successful synthesis of Cu-doped ZnO nanoparticles from tobacco stem extract suggests an environmentally friendly approach. The photocatalytic degradation studies demonstrate the superior activity of 5% Cu-doped ZnO against methylene blue, attributed to synergistic effects between Cu and ZnO. Cu-doped ZnO has the potential to significantly enhance solar cell efficiency. The demonstrated photocatalytic and photovoltaic activities of Cu-doped ZnO open avenues for further research in optimizing their performance for practical applications in solar energy technologies and sustainable energy production.Öğe Effect of a novel metal-free green synthesis catalyst on the positive role of microwave irradiation in hydrogen production from the hydrolysis of sodium borohydride(Elsevier, 2024) Ekinci, Arzu; Sahin, Omer; Baytar, OrhanThis study demonstrates the synthesis of hydrochar, a high-value material, from watermelon seed husk, a lowvalue waste material, using the hydrothermal synthesis method. The microwave power effect plays an important role in the use of metal-free and environmentally friendly catalysts for the hydrolysis of sodium borohydride. The XRD, BET, SEM, and FTIR analyses characterized the catalyst. X-ray diffraction revealed the catalyst structure to be cellulosic. The surface area and total pore volume were 1.063 m2/g and 0.0195 cm3/g, respectively, in BET analysis. According to the IUPAC classification, the catalyst conformed to the type III isotherm. This study investigated how good the catalyst for the hydrolysis of sodium borohydride was when it was exposed to microwave irradiation at different microwave powers, solution temperatures, and catalyst amounts. The Langmuir-Hinshelwood and nth-order kinetic models calculated the activation energies to be 82.192 and 83.35 kJ/mol, respectively. The use of bio-waste hydrochar as a catalyst in the hydrolysis of sodium borohydride in the microwave environment shows promising results in the search for metal-free catalysts.Öğe Effect of environmentally friendly and efficient metal-free hydrochars as catalysts on sodium borohydride hydrolysis(Elsevier Sci Ltd, 2023) Baytar, Orhan; Sahin, Omer; Ekinci, ArzuEnvironmentally friendly, metal-free catalysts are important to synthesize and use, as are catalysts made from biomass-based. This study aims to obtain hydrochars from pine cones and rheum ribes shells by the hydrothermal method and use this hydrochar as a catalyst in sodium borohydride hydrolysis.The characterization of the synthesized catalyst hydrochars was carried out by XRD, BET, SEM, EDX, ICP-OES and FTIR analyses. X-ray diffraction analysis of pinecone hydrochar and rheum ribes shells hydrochar has revealed that they are both amorphous and crystalline in structure. The BET surface areas of the two hydrochars are 1.6 m2/g and 19.01 m2/g, respectively. The activity of hydrochars on the hydrolysis of sodium borohydride was evaluated under microwave irradiation at different temperatures, catalyst amounts, and different microwave powers. The hydrolysis kinetics of NaBH4 in the presence of pine cone and rheum ribes shells hydrochars cat-alysts were determined according to the nth-order and the Langmuir-Hinshelwood kinetic models. The activation energies for the rheum ribes shells and pine cone hydrochars catalysts were calculated to be 88.29 kJ/mol and 78 kJ/mol, respectively. It was concluded that hydrochar prepared from waste material extract through the eco-friendly green synthesis method is promising for the hydrolysis of NaBH4.Öğe Enhanced benzene vapor adsorption through microwave-assisted fabrication of activated carbon from peanut shells using ZnCl2 as an activating agent(Springer, 2024) Kutluay, Sinan; Şahin, Ömer; Baytar, OrhanHerein, microwave-assisted activated carbon (MW-AC) was fabricated from peanut shells using a ZnCl2 activator and utilized for the first time to eliminate benzene vapor as a volatile organic compound (VOC). During the MW-AC production process, which involved two steps—microwave treatment and muffle furnace heating—we investigated the effects of various factors and achieved the highest iodine number of 1250 mg/g. This was achieved under optimal operating conditions, which included a 100% impregnation ratio, CO2 as the gas in the microwave environment, a microwave power set at 500 W, a microwave duration of 10 min, an activation temperature of 500 °C and an activation time of 45 min. The structural and morphological properties of the optimized MW-AC were assessed through SEM, FTIR, and BET analysis. The dynamic adsorption process of benzene on the optimized MW-AC adsorbent, which has a significant BET surface area of 1204.90 m2/g, was designed using the Box-Behnken approach within the response surface methodology. Under optimal experimental conditions, including a contact duration of 80 min, an inlet concentration of 18 ppm, and a temperature of 26 °C, the maximum adsorption capacity reached was 568.34 mg/g. The experimental data are better described by the pseudo-second-order kinetic model, while it is concluded that the equilibrium data are better described by the Langmuir isotherm model. MW-AC exhibited a reuse efficiency of 86.54% for benzene vapor after five consecutive recycling processes. The motivation of the study highlights the high adsorption capacity and superior reuse efficiency of MW-AC adsorbent with high BET surface area against benzene pollutant. According to our results, the developed MW-AC presents itself as a promising adsorbent candidate for the treatment of VOCs in various industrial applications. © The Author(s) 2024.Öğe Enhanced electrochemical double-layer capacitive performance with CO2 plasma treatment on activated carbon prepared from pyrolysis of pistachio shells(Pergamon-Elsevier Science Ltd, 2020) Sahin, Omer; Yardim, Yavuz; Baytar, Orhan; Saka, CaferThis study reports an original approach based on the CO2 plasma treatment on modification of the chemical or physical properties of activated carbon(AC) from the pistachio shells as a waste for application as electrochemical double-layer capacitors(EDLC). In the AC production experiments, impregnation ratio, impregnation pre-treatment temperature, activation temperature and activation time are investigated. In the AC modification experiments with plasma treatment, the effects of plasma gases, plasma power and plasma time are performed. The results of the different conditions indicated that the structural properties of the obtained AC were significantly dependent on the plasma and pyrolysis parameters. The surface properties of the raw AC and plasma-treated AC (PTAC) with X-ray photoelectron spectroscopy (XPS), nitrogen adsorption technique, and scanning electron microscope (SEM) are characterized. Surface area values for the raw AC and PTAC are 768 and 1250 m(2) g(-1), respectively. A change in the peak positions and an increase in the percentage of oxygen of the AC treated with CO2 plasma were obtained from XPS results. After 15 min of CO2 plasma activation, a significant increase in the capacitance of up to about 141% was obtained as a 118.4 F g(-1) compared to 49.98 F g(-1) for untreated AC. The results show that the plasma treatment on the specific surface area and surface functional groups of AC has a significant impact. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Enhancement in incident photon-to-current conversion efficiency of manganese-decorated activated carbon-supported cadmium sulfide nanocomposite(Springer, 2022) Batur, Ebru; Baytar, Orhan; Horoz, Sabit; Sahin, Omer; Kutluay, SinanIn the current study, cadmium sulfide (CdS), activated carbon (AC)-supported CdS (CdS/AC) and manganese (Mn)-decorated CdS/AC semiconductor materials fabricated by the chemical precipitation method are used as sensitizers and the incident photon-to-current efficiency (IPCE) values of the obtained semiconductor-based solar cell structures are evaluated. The fabricated semiconductor materials, which provide the best IPCE value, are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). SEM images of the Mn-decorated CdS/AC semiconductor material showed that CdS and Mn settled in the mesopores, forming a homogeneous microporous structure on the surface. Based on the XRD, EDX and XPS analysis findings, it is concluded that CdS, CdS/AC and Mn-decorated CdS/AC semiconductor materials are successfully fabricated. The optimum concentration of CdS with a maximum IPCE (%) is found as 10% (for CdS/AC). An extraordinary increase in IPCE (%) of 3% Mn-decorated 10% CdS/AC semiconductor material (from 4.70 to 55.09%) is observed compared to pure CdS. Thus, the ability to increase the photovoltaic efficiency of CdS-based solar cells, which are widely used in photovoltaic applications, with AC support has been clearly demonstrated. The findings of this study indicates that Mn-decorated CdS/AC fabrication is an effective strategy to greatly increase the IPCE (%) and Mn-decorated CdS/AC is a promising nanocomposite to improve solar cell efficiency of semiconductor-based solar cell structures.Öğe Equilibrium, kinetic and thermodynamic studies for dynamic adsorption of benzene in gas phase onto activated carbon produced from elaeagnus angustifolia seeds(Elsevier, 2019) Kutluay, Sinan; Baytar, Orhan; Şahin, ÖmerAdsorption of pollutants onto activated carbon is very important in air purification systems. In this study, the dynamic adsorption of benzene in gas phase onto activated carbon which was produced from the elaeagnus angustifolia seeds, was investigated using a laboratory-scale continuous flow fixed-bed reactor system, under atmospheric pressure. The effects of the adsorption conditions such as activated carbon particle size (180–500 μm), nitrogen (N2) gas flow rate (0.050–0.120 L min−1) as the benzene in gas phase carrier, amount of activated carbon (0.10–0.75 g), concentration of benzene in gas phase at the inlet (9.95–14.85 ppm) and the adsorption temperature (293–323 K) on both the adsorption capacity and the adsorption efficiency were examined. Adsorption efficiency was achieved up to 100% under various adsorption conditions. Adsorption kinetics data were analyzed by using the Pseudo-First Order and Pseudo-Second Order kinetic models. Langmuir, Freundlich and Dubinin-Radushkevich models were used for the analysis of adsorption isotherms. The results showed that the Langmuir isotherm and Pseudo-Second Order models described the experimental data better when compared to other models. The maximum monolayer adsorption capacity (qmax) of activated carbon was determined to be 99.8 mg g−1 for 303 K. Thermodynamic analyzes indicated that the adsorption process of benzene in gas phase onto activated carbon was spontaneous (ΔG°<0), exothermic (ΔH°<0) and physical (ΔH°<20 kJ mol−1).Öğe Etkili Aktif Karbon Destekli CdS Fotokatalizörlerin Fotokatalitik Uygulamaları(2020) İzgi, Mehmet Sait; Zörer, Cihan; Baytar, Orhan; Horoz, Sabit; Şahin, ÖmerFarklı aktif karbon konsantrasyonları (%5, %10 ve %20) kullanılarak aktif karbon destekli CdS fotokatalizörlerhidrotermal tekniği kullanılarak sentezlenmiştir. Sentezlenen %5, %10 ve %20 aktif karbon destekli CdSfotokatalizörler sırasıyla CdS_1, CdS_2 ve CdS_3 şeklinde isimlendirilmiştir. Fotokatalitik deneylerin birinciaşamasında metilen mavisinin fotokatalitik bozundurulmasında en iyi fotokatalitik aktiviteye sahip olanfotokatalizör belirlendi. Daha sonra bu fotokatalizör varlığında, katalizör miktarı ve boya konsantrasyonu gibifarklı parametrelerin metilen mavisinin fotokatalitik bozundurulmasını nasıl etkilediği incelenmiştir. Çalışmanınson kısmından en iyi fotokatalitik aktiviteye sahip olan fotokatalizörün yapısal, morfolojik ve elementselözellikleri sırasıyla x-ışını difraksiyonu (XRD), taramalı elektron mikroskobu (SEM) ve enerji dağıtıcı x-ışını(EDX) cihazları ile karakterize edilmiştir.Öğe Facile green synthesis of a novel NiO and its catalytic effect on methylene blue photocatalytic reduction and sodium borohydride hydrolysis(Taylor & Francis Inc, 2024) Baytar, OrhanNiO nanoparticles were synthesized from pine cone extract by green synthesis method, which is a simple, cost-effective, environmentally friendly and sustainable method. The particle size of NiO nanoparticles was determined to be in the range of 10-25 nm by X-diffraction differential and transmission electron microscope analysis, and the bandgap energy of NiO nanoparticles was determined to be 2.66 eV. The catalytic effect of NiO nanoparticles in both microwave-assisted sodium borohydride hydrolysis and photocatalytic reduction of methylene blue was examined and it was determined that they had a high catalytic effect in both applications. It was determined that the hydrogen production rate in sodium borohydride hydrolysis was 1135 mL/g/min. The activation energy of sodium borohydride hydrolysis is 29.69 kJ/mol and 29.59 kJ/mol for the nth-order and Langmuir Hinshelwood kinetic models, respectively. In the photocatalytic reduction of methylene blue with NaBH4, it was determined that the reduction did not occur in the absence of a catalyst, but in the presence of the catalyst, the reduction occurred 98% in 3 min. It was determined that NiO nanoparticles were used five times in the photocatalytic reduction of methylene blue and the reduction efficiency for the fifth time was 93%. It was determined that the photocatalytic reduction of methylene blue was pseudo-first order and the rate constant was 1.63 s-1. It was determined that NiO nanoparticles synthesized by the environmentally friendly green synthesis method can be used as catalysts for two different applications.
