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Dr. Kubilay Tekin
Department of Environmental Engineering, Karabuk University, Karabuk, 78050, Turkey

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0 Biomass Conversion
0 Pyrolysis
0 Renewable Energy
0 Energy and Environment
0 biofuel production

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Pyrolysis
Biomass Conversion
Renewable Energy
hydrothermal treatment

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Journal article
Published: 29 June 2021 in Sustainable Chemistry and Pharmacy
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Hydrothermal liquefaction (HTL) of olive oil residues was conducted at various temperatures (250, 270, 300 and 330 °C) and residence times (5, 15, 30, and 60 min). The effect of metal chlorides (AlCl3 and SnCl2) on product yields and compositions was investigated under optimum conditions (300 °C for 15 min). Bio-oil and solid residue yields from the non-catalytic run were 30.8 and 31.8 wt%, respectively. Use of metal chlorides led to decreased bio-oil yields and increased solid residue yields. Experiments were also carried out using methanol, with and without catalysts, and under identical conditions. The bio-oil yield from the non-catalytic supercritical methanol liquefaction (SCMEL) was 33.5 wt%, increasing to 40.3 wt% with AlCl3, however, SnCl2 had almost no effect on bio-oil yield. The heating values of bio-oils from HTL runs were higher than those of corresponding SCMEL runs, and the highest heating value of bio-oil (34 MJ/kg) was obtained with AlCl3. Phenols and ketones were major bio-oil constituents in the HTL runs, whereas esters were the most abundant compounds in bio-oils from SCMEL runs.

ACS Style

Tolgahan Evcil; Kubilay Tekin; Suat Ucar; Selhan Karagoz. Hydrothermal liquefaction of olive oil residues. Sustainable Chemistry and Pharmacy 2021, 22, 100476 .

AMA Style

Tolgahan Evcil, Kubilay Tekin, Suat Ucar, Selhan Karagoz. Hydrothermal liquefaction of olive oil residues. Sustainable Chemistry and Pharmacy. 2021; 22 ():100476.

Chicago/Turabian Style

Tolgahan Evcil; Kubilay Tekin; Suat Ucar; Selhan Karagoz. 2021. "Hydrothermal liquefaction of olive oil residues." Sustainable Chemistry and Pharmacy 22, no. : 100476.

Review
Published: 05 August 2020 in Sustainable Energy & Fuels
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Fossil fuels must be replaced with renewable energy resources to ensure sustainable development, reduce the dependence on fossil fuels, address environmental challenges including climate change.

ACS Style

Koray Alper; Kubilay Tekin; Selhan Karagöz; Arthur J. Ragauskas. Sustainable energy and fuels from biomass: a review focusing on hydrothermal biomass processing. Sustainable Energy & Fuels 2020, 4, 4390 -4414.

AMA Style

Koray Alper, Kubilay Tekin, Selhan Karagöz, Arthur J. Ragauskas. Sustainable energy and fuels from biomass: a review focusing on hydrothermal biomass processing. Sustainable Energy & Fuels. 2020; 4 (9):4390-4414.

Chicago/Turabian Style

Koray Alper; Kubilay Tekin; Selhan Karagöz; Arthur J. Ragauskas. 2020. "Sustainable energy and fuels from biomass: a review focusing on hydrothermal biomass processing." Sustainable Energy & Fuels 4, no. 9: 4390-4414.

Research article
Published: 30 July 2020 in Fullerenes, Nanotubes and Carbon Nanostructures
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Oak wood samples were converted into activated carbons via chemical activation with KOH. The effects of KOH concentration and temperature on the yields and characteristics of the activated carbons were investigated; the yield of the activated carbons decreased with increased temperature and impregnation ratio. The lowest yield of activated carbon was obtained at the highest temperature (800 °C), with the highest KOH concentration of 100 wt%. The BET surface area of the activated carbons was comparable to that of commercially-activated carbon. The highest BET surface area of the activated carbon was 1662 m2.g−1, obtained at 800 °C with 50 wt% KOH concentration. KOH activation resulted in microporosity development in activated carbons.

ACS Style

Oznur Bag; Kubilay Tekin; Selhan Karagoz. Microporous activated carbons from lignocellulosic biomass by KOH activation. Fullerenes, Nanotubes and Carbon Nanostructures 2020, 28, 1030 -1037.

AMA Style

Oznur Bag, Kubilay Tekin, Selhan Karagoz. Microporous activated carbons from lignocellulosic biomass by KOH activation. Fullerenes, Nanotubes and Carbon Nanostructures. 2020; 28 (12):1030-1037.

Chicago/Turabian Style

Oznur Bag; Kubilay Tekin; Selhan Karagoz. 2020. "Microporous activated carbons from lignocellulosic biomass by KOH activation." Fullerenes, Nanotubes and Carbon Nanostructures 28, no. 12: 1030-1037.

Journal article
Published: 30 June 2020 in Fuel
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This study is the first to investigate the effect of combined Lewis and Brønsted acid catalysts on the hydrothermal carbonization of fir wood samples; here, hydrothermal carbonization of fir wood–with and without catalyst–was performed. In non-catalytic runs, the effects of temperature and residence time on hydrochar yields were investigated; temperature significantly affected hydrochar yields, whereas residence time had very little effect. A gradual increase in temperature resulted in a decrease in hydrochar yields while increasing the carbon content of hydrochars. At all tested temperatures, the use of a catalyst led to a decrease in hydrochar yields. The highest heating value of 29.12 MJ kg−1 was obtained at the highest temperature (275 °C) and the longest residence time (24 h). The use of catalysts slightly decreased the heating values. The hydrochars were mainly in the class of lignite coal; hydrochar obtained at 275 °C and a residence time of 12 h–either with or without catalysts–was classified as bituminous coal. Irregular carbon sphere formation was observed at all temperatures tested in the catalytic runs; however, no carbon spheres were observed in the non-catalytic runs. XRD patterns of hydrochars from the non-catalytic runs were similar for temperatures of 225, 250 and 275 °C; the peak observed at 2θ of 22° broadened after HTC processing. In the catalytic runs, two new peaks at 2θ of 38° and 49° were observed, in addition to broadened peaks (2θ = 22°). The use of catalysts led to the formation of the secondary char.

ACS Style

Tolgahan Evcil; Hamza Simsir; Suat Ucar; Kubilay Tekin; Selhan Karagoz. Hydrothermal carbonization of lignocellulosic biomass and effects of combined Lewis and Brønsted acid catalysts. Fuel 2020, 279, 118458 .

AMA Style

Tolgahan Evcil, Hamza Simsir, Suat Ucar, Kubilay Tekin, Selhan Karagoz. Hydrothermal carbonization of lignocellulosic biomass and effects of combined Lewis and Brønsted acid catalysts. Fuel. 2020; 279 ():118458.

Chicago/Turabian Style

Tolgahan Evcil; Hamza Simsir; Suat Ucar; Kubilay Tekin; Selhan Karagoz. 2020. "Hydrothermal carbonization of lignocellulosic biomass and effects of combined Lewis and Brønsted acid catalysts." Fuel 279, no. : 118458.

Journal article
Published: 05 June 2020 in Fuel
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Direct one-pot transformation of lignocellulosic biomass has been developed as an effective and sustainable strategy to produce fuel blend stocks and high value chemical building blocks. In this wok, a bi-functional catalyst system consisting of palladium supported on carbon (Pd/C) and metal triflates (i.e., Sm(OTf)3, La(OTf)3, and Cu(OTf)2) were shown to promote the biomass liquefaction in both hot-compressed water and supercritical ethanol medium, converting fir wood into oxygenated compounds. The highest bio-oil yield from hydrothermal liquefaction (HTL) was 10.47 wt% over Pd/C whereas the highest bio-oil yield of 49.71 wt% was achieved from supercritical ethanol liquefaction (SCEL) over the bi-functional catalyst system of Pd/C and La(OTf)3. Higher heating values, carbon recovered values and boiling point distributions were further determined for elucidating the physical properties of the bio-oils. Gas chromatography mass spectrometry (GC–MS) analysis of the bio-oils revealed the chemical composition of the bio-oils. Substituted phenols and cyclopentenone/cyclopentanone type compounds consisted of more than 60 area% of the total products from HTL, whereas phenol and esters represented the major products from SCEL. The major reaction pathways are proposed based on the GC–MS results, which include depolymerizaton, isomerization, dehydration, condensation, and hydrogenation.

ACS Style

Naijia Hao; Koray Alper; Himanshu Patel; Kubilay Tekin; Selhan Karagoz; Arthur J. Ragauskas. One-step transformation of biomass to fuel precursors using a bi-functional combination of Pd/C and water tolerant Lewis acid. Fuel 2020, 277, 118200 .

AMA Style

Naijia Hao, Koray Alper, Himanshu Patel, Kubilay Tekin, Selhan Karagoz, Arthur J. Ragauskas. One-step transformation of biomass to fuel precursors using a bi-functional combination of Pd/C and water tolerant Lewis acid. Fuel. 2020; 277 ():118200.

Chicago/Turabian Style

Naijia Hao; Koray Alper; Himanshu Patel; Kubilay Tekin; Selhan Karagoz; Arthur J. Ragauskas. 2020. "One-step transformation of biomass to fuel precursors using a bi-functional combination of Pd/C and water tolerant Lewis acid." Fuel 277, no. : 118200.

Research article
Published: 05 March 2019 in Energy & Fuels
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Hydrothermal liquefaction (HTL) of spruce wood was performed without and with the use of a potassium fluoride doped alumina catalyst (KF/Al2O3) in a bench-top reactor. HTL runs were performed at 250, 300 and 350 °C with residence times of 15, 30 and 60 min. The effects of the catalyst at different catalyst loadings (in concentrations from 10 to 40 wt% of the lignocellulose) on the bio-oil and solid residue yields as well as their properties were investigated. The use of the catalyst increased the bio-oil yields over two-fold and reduced char yields. GC-MS analysis revealed that the bio-oil from the non-catalytic and catalytic runs consisted of aldehydes, ketones, phenols, acids and esters. Among these components, phenolic compounds were dominant in both the non-catalytic and catalytic runs. The relative yields of phenolic compounds increased with catalyst use. The highest heating value was estimated to be approximately 29 MJ kg-1. The boiling point distributions of the bio-oils from both runs revealed that the total naphtha fraction (light and heavy) was comparable with that of crude oil.

ACS Style

Koray Alper; Kubilay Tekin; Selhan Karagoz. Hydrothermal Liquefaction of Lignocellulosic Biomass Using Potassium Fluoride-Doped Alumina. Energy & Fuels 2019, 33, 3248 -3256.

AMA Style

Koray Alper, Kubilay Tekin, Selhan Karagoz. Hydrothermal Liquefaction of Lignocellulosic Biomass Using Potassium Fluoride-Doped Alumina. Energy & Fuels. 2019; 33 (4):3248-3256.

Chicago/Turabian Style

Koray Alper; Kubilay Tekin; Selhan Karagoz. 2019. "Hydrothermal Liquefaction of Lignocellulosic Biomass Using Potassium Fluoride-Doped Alumina." Energy & Fuels 33, no. 4: 3248-3256.

Journal article
Published: 22 September 2018 in Applied Energy
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This study investigates the effects of reaction temperature and catalyst loading on product yields and fuel properties of produced slurry during the alkali catalyzed hydrothermal treatment (HTT) of pine sawdust. The yield of the liquid fraction, or the aqueous product (AP), at process temperatures of 180–260 °C obtained after solid/liquid separation of the slurry ranged from 11.1 to 34.3 wt% on a dry, ash free basis. The fuel quality of the produced slurry, such as the elemental composition and the higher heating value (HHV), was mainly affected by the catalyst loading. An increase in the catalyst loading caused the ash content to increase. Although the increase in temperature leads to a higher liquid fraction in the slurry making it more homogeneous, its contribution to the elemental composition of the whole slurry was limited. HHV of the produced slurry ranged from 12.0 to 16.4 MJ/kg. These values are comparable to that of black liquor (BL), which has previously been shown to be a promising feedstock for gasification in a pilot scale entrained flow gasifier. These results imply the possibility of a fuel switch from BL to the HTT slurry for entrained flow gasification though its gasification reactivity and conversion characteristics must be investigated further.

ACS Style

Akihisa Imai; Flabianus Hardi; Petter Lundqvist; Erik Furusjö; Kawnish Kirtania; Selhan Karagöz; Kubilay Tekin; Kunio Yoshikawa. Alkali-catalyzed hydrothermal treatment of sawdust for production of a potential feedstock for catalytic gasification. Applied Energy 2018, 231, 594 -599.

AMA Style

Akihisa Imai, Flabianus Hardi, Petter Lundqvist, Erik Furusjö, Kawnish Kirtania, Selhan Karagöz, Kubilay Tekin, Kunio Yoshikawa. Alkali-catalyzed hydrothermal treatment of sawdust for production of a potential feedstock for catalytic gasification. Applied Energy. 2018; 231 ():594-599.

Chicago/Turabian Style

Akihisa Imai; Flabianus Hardi; Petter Lundqvist; Erik Furusjö; Kawnish Kirtania; Selhan Karagöz; Kubilay Tekin; Kunio Yoshikawa. 2018. "Alkali-catalyzed hydrothermal treatment of sawdust for production of a potential feedstock for catalytic gasification." Applied Energy 231, no. : 594-599.

Review
Published: 27 August 2018 in ChemSusChem
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Growing energy demand, environmental impact, energy security issues, and rural economic development have encouraged the development of sustainable renewable fuels. Nonfood lignocellulosic biomass is a suitable source for sustainable energy because the biomass feedstocks are low cost, abundant, and carbon neutral. Recent thermochemical conversion studies are frequently directed at converting biomass into high‐quality liquid fuel precursors or chemicals in a single step. Supercritical ethanol has been selected as a promising solvent medium to deconstruct lignocellulosic biomass because ethanol has extraordinary solubility towards lignocellulosic biomass and can be resourced from cellulosic ethanol facilities. This review provides a critical insight into both catalytic and noncatalytic strategies of lignocellulose deconstruction. In this context, the supercritical ethanol deconstruction pathways are thoroughly reviewed; GC‐MS, 1D and 2D NMR spectroscopy, and elemental analysis strategies towards liquid biomass deconstruction products are also critically presented. This review aims to provide readers a broad and accurate roadmap of novel biomass to biofuel conversion techniques.

ACS Style

Kubilay Tekin; Naijia Hao; Selhan Karagoz; Arthur Jonas Ragauskas. Ethanol: A Promising Green Solvent for the Deconstruction of Lignocellulose. ChemSusChem 2018, 11, 3559 -3575.

AMA Style

Kubilay Tekin, Naijia Hao, Selhan Karagoz, Arthur Jonas Ragauskas. Ethanol: A Promising Green Solvent for the Deconstruction of Lignocellulose. ChemSusChem. 2018; 11 (20):3559-3575.

Chicago/Turabian Style

Kubilay Tekin; Naijia Hao; Selhan Karagoz; Arthur Jonas Ragauskas. 2018. "Ethanol: A Promising Green Solvent for the Deconstruction of Lignocellulose." ChemSusChem 11, no. 20: 3559-3575.

Original articles
Published: 13 March 2018 in Biofuels
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In this study, hydrothermal processing was employed to produce crude bio-oil and biochar from waste jujube stones by deploying metal carbonates as catalysts. The effects of metal carbonate catalysts (K2CO3, Na2CO3 and SrCO3) in different concentrations on the product yields and properties were tested for the conversion studies. The use of metal carbonates (K2CO3, Na2CO3 and SrCO3) increased the yield of bio-oil almost twofold, with the highest yield (18.66 wt%) obtained using K2CO3 at a concentration of 10 wt%. (E)- 9-octadecenoic acid (elaidic acid), 2,6-dimethoxyphenol (syringol) and 2-methoxyphenol (guaiacol) were some of the prominent compounds found in the crude bio-oils. The process also resulted in an efficient conversion of jujube stones to biochar with high content of oxygenated functional groups which makes it an effective precursor for various applications. The heating values of the bio-oils and biochars were significantly improved compared to those of the feedstock.

ACS Style

Gamze Nur Aykaç; Kubilay Tekin; Mehmet Kuddusi Akalin; Selhan Karagoz; Madapusi Palavedu Srinivasan; Mehmet Kuddusi Akalın. Production of crude bio-oil and biochar from hydrothermal conversion of jujube stones with metal carbonates. Biofuels 2018, 9, 613 -623.

AMA Style

Gamze Nur Aykaç, Kubilay Tekin, Mehmet Kuddusi Akalin, Selhan Karagoz, Madapusi Palavedu Srinivasan, Mehmet Kuddusi Akalın. Production of crude bio-oil and biochar from hydrothermal conversion of jujube stones with metal carbonates. Biofuels. 2018; 9 (5):613-623.

Chicago/Turabian Style

Gamze Nur Aykaç; Kubilay Tekin; Mehmet Kuddusi Akalin; Selhan Karagoz; Madapusi Palavedu Srinivasan; Mehmet Kuddusi Akalın. 2018. "Production of crude bio-oil and biochar from hydrothermal conversion of jujube stones with metal carbonates." Biofuels 9, no. 5: 613-623.

Journal article
Published: 01 September 2017 in Applied Catalysis A: General
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ACS Style

Mehmet K. Akalin; Parthapratim Das; Koray Alper; Kubilay Tekin; Arthur J. Ragauskas; Selhan Karagöz. Deconstruction of lignocellulosic biomass with hydrated cerium (III) chloride in water and ethanol. Applied Catalysis A: General 2017, 546, 67 -78.

AMA Style

Mehmet K. Akalin, Parthapratim Das, Koray Alper, Kubilay Tekin, Arthur J. Ragauskas, Selhan Karagöz. Deconstruction of lignocellulosic biomass with hydrated cerium (III) chloride in water and ethanol. Applied Catalysis A: General. 2017; 546 ():67-78.

Chicago/Turabian Style

Mehmet K. Akalin; Parthapratim Das; Koray Alper; Kubilay Tekin; Arthur J. Ragauskas; Selhan Karagöz. 2017. "Deconstruction of lignocellulosic biomass with hydrated cerium (III) chloride in water and ethanol." Applied Catalysis A: General 546, no. : 67-78.

Journal article
Published: 01 November 2016 in Journal of the Energy Institute
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ACS Style

Kubilay Tekin; M. Kuddusi Akalin; Selhan Karagöz. The effects of water tolerant Lewis acids on the hydrothermal liquefaction of lignocellulosic biomass. Journal of the Energy Institute 2016, 89, 627 -635.

AMA Style

Kubilay Tekin, M. Kuddusi Akalin, Selhan Karagöz. The effects of water tolerant Lewis acids on the hydrothermal liquefaction of lignocellulosic biomass. Journal of the Energy Institute. 2016; 89 (4):627-635.

Chicago/Turabian Style

Kubilay Tekin; M. Kuddusi Akalin; Selhan Karagöz. 2016. "The effects of water tolerant Lewis acids on the hydrothermal liquefaction of lignocellulosic biomass." Journal of the Energy Institute 89, no. 4: 627-635.

Review
Published: 28 October 2016 in Environmental Chemistry Letters
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A sustainable source of energy production can be provided using renewable resources. For instance, biomass is transformed into biofuels using several techniques such as supercritical fluid extraction, an effective thermochemical process. Here we review results on biofuels obtained from lignocellulosic and algal biomass using supercritical fluids. Biofuel yield and composition are controlled by operating conditions such as extraction temperature, pressure, biomass and solvent type, and the presence of catalysts. The extraction temperature is the major factor controlling biofuel yield. Biofuel yields can also be improved with the use of catalysts. Major compounds in biofuels from lignocellulosic biomass are phenols, catechols, guaiacols, syringols, syringaldehydes, syringyl acetone, acids, and esters. Most of these compounds are produced by lignin decomposition in lignocellulose. Furfural and derivatives are produced by the decomposition of cellulose and hemicellulose. Fatty acid alkyl esters are formed from lignin fragmentation by condensation of compounds bearing C–O or C=O. Prominent compounds in biofuels from algal biomass are saturated or unsaturated fatty acid alkyl esters.

ACS Style

Mehmet K. Akalın; Kubilay Tekin; Selhan Karagöz. Supercritical fluid extraction of biofuels from biomass. Environmental Chemistry Letters 2016, 15, 29 -41.

AMA Style

Mehmet K. Akalın, Kubilay Tekin, Selhan Karagöz. Supercritical fluid extraction of biofuels from biomass. Environmental Chemistry Letters. 2016; 15 (1):29-41.

Chicago/Turabian Style

Mehmet K. Akalın; Kubilay Tekin; Selhan Karagöz. 2016. "Supercritical fluid extraction of biofuels from biomass." Environmental Chemistry Letters 15, no. 1: 29-41.

Journal article
Published: 18 January 2016 in CLEAN – Soil, Air, Water
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Ultrasound-assisted emulsification solidified floating organic drop microextraction was used for preconcentration of trace amounts of bismuth prior to its determination by flame atomic absorption spectrometry. The bismuth ions were extracted by an organic microdrop composed of 1-dodecanol containing the complexing agent dithizone. The method involves the transferring of the bismuth ion from the aqueous solution to the organic phase under mild conditions. It combines the advantages of simplicity of liquid–liquid microextraction with the quickness of the ultrasound technique. All crucial parameters affecting the analytical performance were studied. Under optimum conditions, the enhancement factor was determined to be 29. The detection limit and precision were obtained as 7.5 ng/mL and 1.03% (n = 9, 100 ng/mL), respectively. The accuracy of the developed method was evaluated by analyzing a certified reference material and was successfully applied for the analysis of water samples.

ACS Style

Kubilay Tekin; Ilknur Durukan. Preconcentration of Bismuth(III) by Ultrasound Assisted Emulsification Solidified Floating Organic Drop Microextraction and Analysis by Atomic Absorption Spectrometry. CLEAN – Soil, Air, Water 2016, 44, 356 -361.

AMA Style

Kubilay Tekin, Ilknur Durukan. Preconcentration of Bismuth(III) by Ultrasound Assisted Emulsification Solidified Floating Organic Drop Microextraction and Analysis by Atomic Absorption Spectrometry. CLEAN – Soil, Air, Water. 2016; 44 (4):356-361.

Chicago/Turabian Style

Kubilay Tekin; Ilknur Durukan. 2016. "Preconcentration of Bismuth(III) by Ultrasound Assisted Emulsification Solidified Floating Organic Drop Microextraction and Analysis by Atomic Absorption Spectrometry." CLEAN – Soil, Air, Water 44, no. 4: 356-361.

Journal article
Published: 15 January 2016 in CLEAN – Soil, Air, Water
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ACS Style

Kubilay Tekin; Mehmet K. Akalin; Lokman Uzun; Selhan Karagöz; Sema Bektaş; Adil Denizli. Adsorption of Pb(II) and Cd(II) Ions Onto Dye-Attached Sawdust. CLEAN – Soil, Air, Water 2016, 44, 339 -344.

AMA Style

Kubilay Tekin, Mehmet K. Akalin, Lokman Uzun, Selhan Karagöz, Sema Bektaş, Adil Denizli. Adsorption of Pb(II) and Cd(II) Ions Onto Dye-Attached Sawdust. CLEAN – Soil, Air, Water. 2016; 44 (4):339-344.

Chicago/Turabian Style

Kubilay Tekin; Mehmet K. Akalin; Lokman Uzun; Selhan Karagöz; Sema Bektaş; Adil Denizli. 2016. "Adsorption of Pb(II) and Cd(II) Ions Onto Dye-Attached Sawdust." CLEAN – Soil, Air, Water 44, no. 4: 339-344.

Journal article
Published: 01 December 2015 in Industrial Crops and Products
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Ultrasound-assisted extraction of essential oils from clove was carried out using central composite design (CCD). The extraction parameters were optimized with response surface methodology (RSM). Three independent variables were extraction temperatures (ranging from 32 to 52 °C), extraction times (ranging from 30 to 60 min), and plant concentrations (ranging from 3 to 7%). The dependent (response) variable was clove extract. In this study, all the experiments were carried out in an ultrasound bath with a frequency of 53 kHZ. A high coefficient of correlation (0.94) was obtained between the predicted and actual clove extract yields. This result demonstrates the validity of the model used in the experiment. The statistical results showed that the extraction temperature had the most significant influence on the clove extract yield. The clove extract contained the following compounds: eugenol, α-caryophyllene, and 2-methoxy-4-(2-propenyl) phenol acetate. The major compound in the clove extract was eugenol. Antibacterial studies showed that essential oils derived from the ultrasound extraction of clove may be used as alternative bactericidal and bacteriostatic agents in the pharmaceutical industry.

ACS Style

Kubilay Tekin; Mehmet Kuddusi Akalın; Mine Gül Şeker. Ultrasound bath-assisted extraction of essential oils from clove using central composite design. Industrial Crops and Products 2015, 77, 954 -960.

AMA Style

Kubilay Tekin, Mehmet Kuddusi Akalın, Mine Gül Şeker. Ultrasound bath-assisted extraction of essential oils from clove using central composite design. Industrial Crops and Products. 2015; 77 ():954-960.

Chicago/Turabian Style

Kubilay Tekin; Mehmet Kuddusi Akalın; Mine Gül Şeker. 2015. "Ultrasound bath-assisted extraction of essential oils from clove using central composite design." Industrial Crops and Products 77, no. : 954-960.

Journal article
Published: 01 December 2015 in Industrial Crops and Products
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ACS Style

Mehmet K. Akalın; Kubilay Tekin; Mehmet Akyüz; Selhan Karagöz. Sage oil extraction and optimization by response surface methodology. Industrial Crops and Products 2015, 76, 829 -835.

AMA Style

Mehmet K. Akalın, Kubilay Tekin, Mehmet Akyüz, Selhan Karagöz. Sage oil extraction and optimization by response surface methodology. Industrial Crops and Products. 2015; 76 ():829-835.

Chicago/Turabian Style

Mehmet K. Akalın; Kubilay Tekin; Mehmet Akyüz; Selhan Karagöz. 2015. "Sage oil extraction and optimization by response surface methodology." Industrial Crops and Products 76, no. : 829-835.

Journal article
Published: 15 August 2015 in Clean Technologies and Environmental Policy
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A central composite design was applied to the extraction of bio-oils from flax seeds under supercritical ethanol (Sc-EtOH) conditions. The effects of three factors (temperature, time, and biomass concentration) on bio-oil and biomass conversion yields were examined. Extraction temperature was statistically found to be the most significant factor which affected both bio-oil yield and biomass conversion. The predicted results matched the experimental results with the following coefficient of determination: (R 2) 0.95 for bio-oil yield and 0.92 for biomass conversion yield. The composition of bio-oils consisted mainly of fatty acid ester derivatives, and other oxygenated hydrocarbons. Based on the relative concentrations of the compounds, the major compound was ethyl oleate.

ACS Style

Kubilay Tekin; Mehmet K. Akalin; Selhan Karagöz. Experimental design for extraction of bio-oils from flax seeds under supercritical ethanol conditions. Clean Technologies and Environmental Policy 2015, 18, 461 -471.

AMA Style

Kubilay Tekin, Mehmet K. Akalin, Selhan Karagöz. Experimental design for extraction of bio-oils from flax seeds under supercritical ethanol conditions. Clean Technologies and Environmental Policy. 2015; 18 (2):461-471.

Chicago/Turabian Style

Kubilay Tekin; Mehmet K. Akalin; Selhan Karagöz. 2015. "Experimental design for extraction of bio-oils from flax seeds under supercritical ethanol conditions." Clean Technologies and Environmental Policy 18, no. 2: 461-471.

Journal article
Published: 23 July 2015 in Clean Technologies and Environmental Policy
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This study investigates the production of spherical carbons from cellulose under sub- and supercritical ethanol conditions with and without the addition of a potassium hydroxide (KOH) catalyst. Different temperatures (200 and 280 °C), residence times (0.5, 1, 2, and 4 h), and KOH concentrations (5, 10, and 20 wt% of cellulose) were used for the carbonization process. Carbon spheres could only be obtained under supercritical ethanol conditions (at 280 °C and 9.5 MPa). Supercritical ethanol decreases the oxygen content by a significant amount, thereby increasing the heating value. Morphological studies show that the carbons are essentially spherical of different sizes depending on the operating conditions (such as the presence of a catalyst and time). For the first time, we showed that spherical carbons can be obtained under supercritical ethanol conditions. This is a useful result as, for instance, ethanol can be produced from cellulose, and this opens the possibility for the development of a green and simple procedure to synthesize carbon spheres that may have many different applications including gas separation, catalysis, and energy storage.

ACS Style

Kubilay Tekin; Filoklis D. Pileidis; Mehmet K. Akalin; Selhan Karagöz. Cellulose-derived carbon spheres produced under supercritical ethanol conditions. Clean Technologies and Environmental Policy 2015, 18, 331 -338.

AMA Style

Kubilay Tekin, Filoklis D. Pileidis, Mehmet K. Akalin, Selhan Karagöz. Cellulose-derived carbon spheres produced under supercritical ethanol conditions. Clean Technologies and Environmental Policy. 2015; 18 (1):331-338.

Chicago/Turabian Style

Kubilay Tekin; Filoklis D. Pileidis; Mehmet K. Akalin; Selhan Karagöz. 2015. "Cellulose-derived carbon spheres produced under supercritical ethanol conditions." Clean Technologies and Environmental Policy 18, no. 1: 331-338.

Research article
Published: 24 June 2015 in Energy & Fuels
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Hydrothermal conversion studies were performed (bio-oil obtained under hydrothermal conditions) using Russian olive (Elaeagnus angustifolia L.) seeds as a waste biomass at different temperatures and different residence times. After the conditions where the highest yield of bio-oil was found, a mussel shell catalyst (which is a source of calcium oxide when calcined at T > 950 °C) was applied for the first time for the hydrothermal conversion of biomass. To compare and evaluate the catalytic performance of the catalyst, the effects of the catalyst on product distributions, elemental contents, and high heating values of products and bio-oil compositions were investigated. The use of the catalyst significantly increased the bio-oil and conversion yields. The bio-oils were analyzed by a gas chromatograph–mass spectrometer (GC–MS). Characterization studies of the catalyst were completed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, and X-ray diffraction (XRD) analysis. This study exclusively focuses on the bio-oil and solid residue yield to demonstrate the effects of the catalyst derived from a waste biomass. Suggestions for further studies are provided at the end of the Conclusion.

ACS Style

Kubilay Tekin. Hydrothermal Conversion of Russian Olive Seeds into Crude Bio-oil Using a CaO Catalyst Derived from Waste Mussel Shells. Energy & Fuels 2015, 29, 4382 -4392.

AMA Style

Kubilay Tekin. Hydrothermal Conversion of Russian Olive Seeds into Crude Bio-oil Using a CaO Catalyst Derived from Waste Mussel Shells. Energy & Fuels. 2015; 29 (7):4382-4392.

Chicago/Turabian Style

Kubilay Tekin. 2015. "Hydrothermal Conversion of Russian Olive Seeds into Crude Bio-oil Using a CaO Catalyst Derived from Waste Mussel Shells." Energy & Fuels 29, no. 7: 4382-4392.

Review
Published: 01 December 2014 in Renewable and Sustainable Energy Reviews
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ACS Style

Kubilay Tekin; Selhan Karagöz; Sema Bektaş. A review of hydrothermal biomass processing. Renewable and Sustainable Energy Reviews 2014, 40, 673 -687.

AMA Style

Kubilay Tekin, Selhan Karagöz, Sema Bektaş. A review of hydrothermal biomass processing. Renewable and Sustainable Energy Reviews. 2014; 40 ():673-687.

Chicago/Turabian Style

Kubilay Tekin; Selhan Karagöz; Sema Bektaş. 2014. "A review of hydrothermal biomass processing." Renewable and Sustainable Energy Reviews 40, no. : 673-687.