Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
2 results
Search Results
Article Citation - WoS: 31Citation - Scopus: 35Electrochemical Degradation of Methylene Blue by a Flexible Graphite Electrode: Techno-Economic Evaluation(American Chemical Society, 2022) Ökten, Hatice Eser; Recepoğlu, Yaşar Kemal; Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Genişoğlu, Mesut; Ökten, Hatice Eser; 03.07. Department of Environmental Engineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, electrochemical removal of methylene blue (MB) from water using commercially available and low-cost flexible graphite was investigated. The operating conditions such as initial dye concentration, initial solution pH, electrolyte dose, electrical potential, and operating time were investigated. The Box-Behnken experimental design (BBD) was used to optimize the system's performance with the minimum number of tests possible, as well as to examine the independent variables' impact on the removal efficiency, energy consumption, operating cost, and effluent MB concentration. The electrical potential and electrolyte dosage both improved the MB removal efficiency, since increased electrical potential facilitated production of oxidizing agents and increase in electrolyte dosage translated into an increase in electrical current transfer. As expected, MB removal efficiency increased with longer operational periods. The combined effects of operating time-electrical potential and electrical potential-electrolyte concentration improved the MB removal efficiency. The maximum removal efficiency (99.9%) and lowest operating cost (0.012 $/m3) were obtained for initial pH 4, initial MB concentration 26.5 mg/L, electrolyte concentration 0.6 g/L, electrical potential 3 V, and operating time 30 min. The reaction kinetics was maximum for pH 5, and as the pH increased the reaction rates decreased. Consequent techno-economic assessment showed that electrochemical removal of MB using low-cost and versatile flexible graphite had a competitive advantage.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, Aslı; Yüksel Özşen, Aslı; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn 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] .