Yüksel Özşen, Aslı
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Özşen, Asli Yüksel
Ozsen, Asli Yuksel
Ozsen, A.
Özşen, A.
Yuksel, Asli
Yüksel, Asli
Yüksel, Aslı
Ozsen, Asli Yuksel
Ozsen, A.
Özşen, A.
Yuksel, Asli
Yüksel, Asli
Yüksel, Aslı
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asliyuksel@iyte.edu.tr
Main Affiliation
03.02. Department of Chemical Engineering
Status
Current Staff
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Sustainable Development Goals
1NO POVERTY
0
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2ZERO HUNGER
6
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3GOOD HEALTH AND WELL-BEING
0
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4QUALITY EDUCATION
0
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5GENDER EQUALITY
0
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6CLEAN WATER AND SANITATION
21
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7AFFORDABLE AND CLEAN ENERGY
32
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8DECENT WORK AND ECONOMIC GROWTH
6
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9INDUSTRY, INNOVATION AND INFRASTRUCTURE
19
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10REDUCED INEQUALITIES
0
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11SUSTAINABLE CITIES AND COMMUNITIES
2
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12RESPONSIBLE CONSUMPTION AND PRODUCTION
14
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13CLIMATE ACTION
23
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14LIFE BELOW WATER
4
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15LIFE ON LAND
4
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16PEACE, JUSTICE AND STRONG INSTITUTIONS
0
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17PARTNERSHIPS FOR THE GOALS
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Documents
42
Citations
567
h-index
15
Documents
39
Citations
479
Scholarly Output
56
Articles
36
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102795/17917
Supervised MSc Theses
13
Supervised PhD Theses
2
WoS Citation Count
420
Scopus Citation Count
460
Patents
0
Projects
10
WoS Citations per Publication
7.50
Scopus Citations per Publication
8.21
Open Access Source
33
Supervised Theses
15
| Journal | Count |
|---|---|
| Cellulose | 4 |
| ACS Omega | 3 |
| American Chemical Society (ACS) Meeting | 2 |
| Biomass Conversion and Biorefinery | 2 |
| ChemistrySelect | 2 |
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56 results
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Master Thesis Adsorbent Synthesis for the Recovery of Lithium Water Resources(01. Izmir Institute of Technology, 2022) Kahvecioğlu, Anıl; Yüksel Özşen, Aslı; Yüksel Özşen, AslıLithium is a crucial mineral for the 21st century due to its utilization in a wide range of industries. Lithium demand will increase because of car battery developments and the necessity for power storage. Investigating alternative strategies for resource recovery is the only way to fulfill this unexpected rise properly and sustainably in demand. Adsorption has been discovered to have some technological advantages over other methods. It is considerably less expensive, lacks the chemical resistance present in membranes, lacks the significant electrical demand of electrochemical approaches, as well as the restricted selectivity and challenges in integration into commercial processes. Lithium manganese oxides, also known as lithium ion-sieves, are adsorbents for lithium extraction that have remarkably high selectivity, high adsorption capacity, minimal toxicity, good chemical stability and cheap cost. They are one of the most promising inorganic adsorbents. This research emphasized on the recovery of lithium from water resources through the use of lithium manganese oxide, which were synthesized in laboratory. They were transformed into spherical beads by adding chitosan, followed by crosslinking these beads with epichlorohydrin to increase their adsorption yield, stability, and reusability. Characterization techniques such as SEM, XRD and BET were applied on the adsorbents. Results shows that the adsorbents distributed uniformly, the adsorbent powder was mesoporous, and from the adsorption studies it was found that the adsorbent worked much better in alkaline conditions such as pH 12, optimum adsorbent dosage estimated as 4 g/L and the equilibrium time measured as 10 hours. From the desorption study approximately 95% of Li desorbed for the first cycle, after the second cycle the adsorbent efficiency started to decrease.Master Thesis Production of Bio-Oil From Haelnut Shell Waste by Using Supercritical Ethanol, Acetone and Their Mixtur(Izmir Institute of Technology, 2018) Dal, Orkan; Yüksel Özşen, Aslı; Yüksel Özşen, AslıThe goal of this study was to investigate effect of reaction temperature, reaction time and solvent ratio (ethanol/acetone v/v%) on bio-oil yield, solid conversion and product distribution. Direct thermochemical biomass degradation to obtain bio-oil by using organic solvents is not a new process type, and it has some advantages over hydrothermal liquefaction technique. However, in literature, to our best knowledge, there is no study about hazelnut shell decomposition by using ethanol, acetone and their mixtures at sub/supercritical conditions. In this study, experiments were carried out between 220-300 °C, at three different temperatures (30, 60 & 90 min) for five different solvent ratios. Highest solid conversion achieved at 300 °C by using pure ethanol was 64.2%, whereas highest bio-oil yield was found as 44.2% at 300 °C with 50/50 (EtOH/Ac: v/v). Ethanol and acetone showed different characteristics during the experiments and their effect on the conversion and bio-oil yield were discussed. Statistical analysis showed that time, temperature, ratio and temperature-time are affecting parameters for the conversion and bio oil yield while time-ratio and temperature-ratio are not. According to GC-MS results, product distribution changed with respect to solvent type and ratio.Conference Object Acid-Catalyzed Degradation of Biomass With Hydrothermal Electrolysis for the Production of Value-Added Chemicals(American Chemical Society, 2014) Yüksel, Aslı; Yüksel Özşen, Aslı[No abstract available]Article Citation - WoS: 11Citation - Scopus: 12Novel Hybrid Process for the Conversion of Microcrystalline Cellulose To Value-Added Chemicals: Part 1: Process Optimization(Springer Verlag, 2016) Akın, Okan; Yüksel, AslıIn this paper, a novel hybrid process for the treatment of microcrystalline cellulose (MCC) under hot-compressed water was investigated by applying constant direct current on the reaction medium. Constant current range from 1A to 2A was applied through a cylindrical anode made of titanium to the reactor wall. Reactions were conducted using a specially designed batch reactor (450 mL) made of SUS 316 stainless steel for 30–120 min of reaction time at temperature range of 170–230 °C. As a proton donor H2SO4 was used at concentrations of 1–50 mM. Main hydrolysis products of MCC degradation in HCW were detected as glucose, fructose, levulinic acid, 5-HMF, and furfural. For the quantification of these products, High Performance Liquid Chromatography (HPLC) and Gas Chromatography with Mass Spectroscopy (GC–MS) were used. A ½ fractional factorial design with 2-level of four factors; reaction time, temperature, H2SO4 concentration and applied current with 3 center points were built and responses were statistically analyzed. Response surface methodology was used for process optimization and it was found that introduction of 1A current at 200 °C to the reaction medium increased Total Organic Carbon (TOC) and cellulose conversions to 62 and 81 %, respectively. Moreover, application of current diminished the necessary reaction temperature and time to obtain high TOC and cellulose conversion values and hence decreased the energy required for cellulose hydrolysis to value added chemicals. Applied current had diverse effect on levulinic acid concentration (29.9 %) in the liquid product (230 °C, 120 min., 2 A, 50 mM H2SO4). © 2016, Springer Science+Business Media Dordrecht.Article Machine Learning Integrated Solvothermal Liquefaction of Lignocellulosic Biomass to Maximize Bio-Oil Yield(Elsevier Sci Ltd, 2025) Ocal, Bulutcem; Sildir, Hasan; Yuksel, AsliAccelerating consumption of limited fossil-based for economic growth and simultaneously mitigating greenhouse gas emissions create a dilemma that is waiting to be solved by researchers. In this context, solvothermal liquefaction of lignocellulosic biomass to produce bio-oil is a promising way to obtain green energy. However, maximizing bio-oil is challenging to optimize the operating parameters employing conventional techniques due to the complexity and non-linearity of the process. Lately, machine learning approaches have become powerful tools for addressing complex nonlinear problems by predicting process behavior and regulating operating parameters for optimization by learning from datasets. The current research demonstrates integrating experimental and a developed artificial neural network model to optimize solvothermal liquefaction of pinus brutia, based on temperature, water fraction, and biomass amount in maximizing bio-oil generation for the first time. The highest bio-oil yields were obtained at 31.40 %, 18.68 %, and 39.69 %, respectively, with 4 and 8 g biomass in the presence of water, ethanol, and water/ethanol mixture at 240 degrees C. Under the model conditions, the maximum biooil yield was experimentally verified at 46.20%, which was predicted at 48.8 %. Beyond providing accurate yield predictions, the approach highlights the potential of date-driven modeling to reduce experimental workload and cost while aiding parameter selection to improve efficiency. These outcomes emphasize the importance of machine learning integration into liquefaction process, providing remarkable results for future process design, optimization, and scalability. On the other hand, the study also includes characterization results (ultimate, proximate, FTIR, and GC-MS) of selected products and pinus brutia.Doctoral Thesis Development of a Novel Hybrid Process for the Conversion of Cellulose Into High-Value Chemicals by Applying Voltage in Hot Compressed Water(Izmir Institute of Technology, 2017) Akın, Okan; Yüksel Özşen, AslıIn this study, a novel hybrid method of hydrothermal electrolysis implemented for the decomposition of microcrystalline cellulose (MCC) into high value added chemicals such as levulinic acid, 5-hydroxymethylfurfural (5-HMF), and furfural. The hypothesis of the study was that, when direct current (DC) is applied the formation of ionic and radical species can alter the hydrolysis of cellulose. Based on this hypothesis, the purpose of the study was to build an integrated method of hydrothermal electrolysis that can lower energy requirement of cellulose hydrolysis by altering the selectivity. In order to investigate the individual and coupled effect of operating parameters such as reaction temperature (170-200 ℃), time (30-120 min.), electrolyte concentration (1-50 mM H2SO4), constant current (0-2 A), statistical analysis was conducted by a fractional factorial design. Analysis of variance (ANOVA) test was applied to the main hydrolysis products yields of MCC, total organic carbon (TOC) and cellulose conversion. Based on the response surface plots, 1A of current at 200 ºC maximized TOC yield and cellulose conversions to 62% and 81%, respectively. In order to enhance the selectivity, constant voltage (2.5, 4.0 and 8.0 V) was applied at 200℃. Application of 2.5 V increased TOC (54%) and alter the selectivity of 5-HMF (30%) and levulinic acid (21%). The structural changes in solid residues were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and found that MCC particles functionalized by carboxylic acid and sulfonated groups by application of 2.5 V. Therefore, change in the selectivity values were conducted with the functionalization of MCC particles due to applied voltage under sub-critical conditions.Article Citation - WoS: 4Citation - Scopus: 5Breakthrough Curve Analysis of Phosphorylated Hazelnut Shell Waste in Column Operation for Continuous Harvesting of Lithium From Water(Elsevier, 2024) Recepoğlu, Yaşar Kemal; Arar, Ozguer; Yuksel, AsliIn batch-scale operations, biosorption employing phosphorylated hazelnut shell waste (FHS) revealed excellent lithium removal and recovery efficiency. Scaling up and implementing packed bed column systems necessitates further design and performance optimization. Lithium biosorption via FHS was investigated utilizing a continuous-flow packed-bed column operated under various flow rates and bed heights to remove Li to ultra-low levels and recover it. The Li biosorption capacity of the FHS column was unaffected by the bed height, however, when the flow rate was increased, the capacity of the FHS column decreased. The breakthrough time, exhaustion time, and uptake capacity of the column bed increased with increasing column bed height, whereas they decreased with increasing influent flow rate. At flow rates of 0.25, 0.5, and 1.0 mL/min, bed volumes (BVs, mL solution/mL biosorbent) at the breakthrough point were found to be 477, 369, and 347, respectively, with the required BVs for total saturation point of 941, 911, and 829, while the total capacity was calculated as 22.29, 20.07, and 17.69 mg Li/g sorbent. In the 1.0, 1.5, and 2.0 cm height columns filled with FHS, the breakthrough times were 282, 366, and 433 min, respectively, whereas the periods required for saturation were 781, 897, and 1033 min. The three conventional breakthrough models of the Thomas, Yoon-Nelson, and Modified Dose-Response (MDR) were used to properly estimate the whole breakthrough behavior of the FHS column and the characteristic model parameters. Li's extremely favorable separation utilizing FHS was evidenced by the steep S-shape of the breakthrough curves for both parameters flow rate and bed height. The reusability of FHS was demonstrated by operating the packed bed column in multi-cycle mode, with no appreciable loss in column performance.Publication Meşe Ağacı Artıklarının Hidrotermal Sıvılaştırma ile Biyoyağ Eldesi için Değerlendirilmesi(2023) Yüksel Özşen, AslıYenilenemez bir enerji kaynağı olan fosil yakıtların önümüzdeki yıllarda tamamen tükenecek olması ve halihazırda kullanılırken çevreye verdikleri zararlar dünya genelinde artan enerji ihtiyacıyla da birleşince alternatif enerji üretim yollarının aranmasına başlanmıştır. Biyokütlelerin çeşitli işlem sonucunda gelecekte fosil yakıtların yerini alabilecek ucuz ve çevreci bir alternatif yakıt olan biyoyağa dönüştürülebilmesi son yıllarda literatürde de sıkça çalışılan bir konudur. Farklı katalizör ve solvent kullanımına olanak sağlayan sıvılaştırma işlemi, termokimyasal dönüşümle biyokütleden biyoyağ elde etme yollarından biridir. Özellikle lignoselülozik biyokütleler yüksek selüloz ve hemiselüloz oranlarından ötürü sıvılaştırma işlemi için büyük önem taşımaktadır. Türkiye?nin ormanlık alan ve ormancılık faaliyetleri açısından zengin bir altyapıya sahip olması aynı zamanda değerlendirilmeyen orman atıklarının ortaya çıkmasına sebep olmaktadır. Bu bağlamda, önerilen çalışmada Türkiye?deki ormanlık alanların neredeyse 30%?nu kapsayan meşe ağacı atıklarından farklı solventlerle (su, ethanol, 1-bütanol, 1-hekzanol ve 1,4 dioksan) biyoyağ üretilmesi amaçlanmıştır. Deneyler 210, 240 ve 270 ºC?de 1 ve 2 saatlik süreyle gerçekleştirilmiş ve 1,4 dioksan ile 1 saat 270 ºC?de 53% biyoyağ verimi elde edilmiştir. Aynı zamanda yine aynı koşullar su kullanılarak maksimum değer olan 35 MJ/kg ısıl değerli 25% verimle biyoyağ üretimi başarıyla sağlanmıştır.Master Thesis Selective Catalytic Conversion of Cellulose and Glucose Into Sorbitol in Subcritical Water(Izmir Institute of Technology, 2020) Sapmaz, Aycan; Yüksel, AslıThe goal of this study was to add high value to cellulose as the most abundant source of biomass and glucose by producing a building-block chemical-Sorbitol-, which is not produced in our country and has very large market share. In this manner, the effect of reaction time (1-2 h), catalyst amount (1-2 g) and catalyst type on conversion of cellulose and glucose and yield of sorbitol with presence of various catalysts in subcritical water environment were investigated. The hydrogenation of both glucose and cellulose over Ruthenium based catalysts (Ru/AC, Ru/SiO2, Ru-SBA15 and Ru-SBA15/SO3), using a high pressure-high temperature reactor (Parr 5500 High Pressure Compact Reactor) at a reaction pressure of 5 bar and reaction temperature of 150°C were studied. Ruthenium based catalysts were prepared by wet impregnation method. The synthesized Ru based catalysts with various metal based were characterized by various characterization tools such as Scanning Electron Microscope (SEM), Fouirer Transform Infrared Spektrofotometre (FT-IR) and Brunauer-Emmett-Teller (BET). The catalytic performances were evaluated in hydrogenation of cellulose and also glucose to produce sorbitol under subcritical water conditions. As a result of these analyzes, the highest sorbitol yield and cellulose conversion were found to be 234.98 ppm and 28.64%, respectively for 2 gram of Ru-SiO2 catalyst for 2 hours. For glucose conversion, the catalyst of Ru-SBA15/SO3 showed better catalytic performance than other catalysts.Master Thesis Extraction of Oleuropein From Olive Leaves(01. Izmir Institute of Technology, 2020) Gümüşbulut, Gülin; Yüksel Özşen, Aslı; Yüksel Özşen, AslıThe aim of this study is to obtain oleuropein, which is the main phenolic compound content of olive leaf by soxhlet extraction. Oleuropein has been known in the health field for a long time and is found in high rates in our country. In this context, the effect of various solvent types (ethanol, methanol, acetonitrile and water), extraction time (4 cycles, 4 hours, 8 hours), particle size (250-500 µm and 900-2000 µm) and the pre-treatment applied to the olive leaf on the yield of oleuropein was investigated. The amount of oleuropein in the liquid product was determined using a High Performance Liquid Chromatogram (HPLC). When the grain size of the raw material to be used in extraction was reduced, higher oleuropein was obtained. The use of solvents in an aqueous form resulted in a higher amount of oleuropein compared to pure solvents. Increasing the extraction time caused a significant increase in the amount of oleuropein. On the contrary, it was observed that the pretreatment applied to olive leaves caused a decrease in the yield of oleuropein. As a result of these findings, the highest oleuropein amount and extraction efficiency were obtained after 8 hours of extraction period by using olive leaf with 250-500 μm grain size and 80% methanol solution as the solvent. The highest oleuropein amount was found to be 13.35 oleuropein mg/g dry leaves and the highest extraction efficiency under these conditions was found to be 36 %.