Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Selective Catalytic Hydrogenation of Cellulose into Sorbitol with Ru-Based Catalysts(2022) Orak, C.; Sapmaz, A.; Yüksel Özşen, A.Sorbitol is one of the platform chemicals and can be produced from various renewable and sustainable sources via different processes. Hydrothermal liquefaction is an effective and promising approach to produce sorbitol, since the subcritical reaction media and appropriate catalysts provide a selective production of platform chemicals. In this study, sorbitol was produced from different renewable sources (cellulose and glucose) in the presence of Ru-based catalysts (Ru/SiO2, Ru/AC, Ru/SBA-15, and Ru/SBA-15-SO3) under subcritical conditions. The highest cellulose conversion was achieved as 90% in the presence of Ru/SBA-15-SO3 for 1 h of reaction duration. The highest sorbitol yield (%) by hydrothermal liquefaction of cellulose was obtained as 6.2% by using Ru/AC for 1 h of reaction duration. A total of 99.9% of glucose conversion was achieved in the presence of all catalysts. The highest sorbitol yield (%) by hydrothermal liquefaction of glucose was found as 3.8% for 1 h of reaction duration. Owing to the results of GC-MS analysis, the intermediate products were identified, and, thus, a reaction pathway was proposed. © 2022 TUBITAK. All rights reserved.Article Citation - WoS: 6Citation - Scopus: 8Development of Pro-Angiogenic Wound Dressings From 2-Deoxy (2ddr)-Loaded Decellularized Plant Leaves(SPRINGER, 2023) Dikici, Serkan; Çavdaroğlu, ÇağrıTraditional wound dressings are essential for the treatment of acute and superficial wounds. However, complex wounds require the use of bioactive dressings that promote healing alongside providing a safe barrier for the coverage of the wound site. The addition of growth factors is usually the primary choice to fabricate functionalized wound dressing. However, it is also the main reason for the increase in the cost of a wound dressing and may be associated with several drawbacks, such as the need for a precise drug delivery system to be able to be administered at a narrow effective dose range. 2-deoxy-D-ribose (2dDR) is a cost-effective and promising pro-angiogenic agent that indirectly stimulates vascular endothelial growth factor production to stimulate angiogenesis, and consecutively accelerate wound healing. In this study, we aimed to fabricate a novel wound dressing from 2dDR-loaded decellularized spinach leaves and evaluated its bioactivity on human endothelial cells in vitro. Our results demonstrated that a biocompatible wound dressing biomaterial could successfully be fabricated via the decellularization of spinach leaves using chemical decellularization. The success of decellularization was confirmed quantitatively and qualitatively via determination of the DNA content and Fourier transform infrared spectroscopy, respectively. 2dDR was then easily incorporated into the dressings via physical absorption and released from them in 5 days. The release of 2dDR-releasing decellularized spinach leaves was observed to increase the viability and metabolic activity of human endothelial cells in vitro over 7 days. In conclusion, we demonstrated the fabrication of a novel functionalized biomaterial combining decellularized plant tissues with a promising pro-angiogenic agent, and 2dDR-loaded decellularized spinach leaves appear to have great potential to be used as a bioactive wound dressing to promote angiogenesis and, consecutively, wound healing.Article Citation - WoS: 17Citation - Scopus: 16Synthesis, Characterization and Adsorption Studies of Phosphorylated Cellulose for the Recovery of Lithium From Aqueous Solutions(Editura Acad Romane, 2021) Recepoğlu, Yaşar Kemal; Yüksel, AslıIn this study, pristine cellulose was functionalized by the phosphorylation reaction to make it suitable for lithium separation. After characterization studies of the synthesized adsorbent with SEM, EDX, FTIR, TGA and XPS, the effects of various parameters on the lithium uptake capacity of the adsorbent were examined. The analysis of equilibrium data by several adsorption models showed that maximum adsorption capacity of the adsorbent was found to be 9.60 mg/g at 25 degrees C by the Langmuir model. As initial concentration and contact time increased, adsorption capacity also increased, however, mild temperature (25-35 degrees C) and pH (5-6) were better for the adsorption of lithium. 80% of lithium adsorption within three minutes proved the fast kinetic nature of the adsorbent. A 99.5% desorption efficiency of lithium was achieved with 0.5 M H2SO4, among HCl and NaCl with different molarities. Phosphorylated cellulose was shown to be a favorable adsorbent for the recovery of lithium from aqueous solutions.Article Citation - WoS: 4Citation - Scopus: 4Novel Hybrid Process for the Conversion of Microcrystalline Cellulose To Value-Added Chemicals: Part 3: Detailed Reaction Pathway(Springer Verlag, 2019) Akın, Okan; Yüksel, AslıIn this study, a novel method of hydrothermal electrolysis of microcrystalline cellulose (MCC) under sub-critical water conditions (200 degrees C) was investigated by applying direct current at constant voltage with the presence of acid catalyst of 5mMH(2)SO(4). Direct current at constant voltage of 2.5V, 4.0V and 8.0V was applied between cylindrical anode (titanium) and cathode (reactor wall). Hydrothermal electrolysis reactions were carried out in a batch reactor (450mL-T316) for the reaction time of 240min. Decomposition products of MCC were analyzed by GC-MS and the decomposition pathway of cellulose under applied voltage was postulated. Levoglucosan and levoglucosenone formations were detected as the first hydrolysis products of MCC and further hydrolysis yielded to formation of glucose and fructose. The major decomposition products of cellulose were detected as levulinic acid (LA), 5-HMF and furfural. Further reactions of LA such as electrochemical decarboxylation, dehydration, hydrogenation, resulted in the formation of 2-butanone, 2-butanone-3-hydroxy, gamma-valerolactone, respectively. Most dramatic results on the product distribution were obtained at applied 2.5V voltage in which LVA and 5-HMF were selectively produced. [GRAPHICS] .