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    A Novel Tea factory waste metal-free catalyst as promising supercapacitor electrode for hydrogen production and energy storage: A dual functional material
    (Elsevier Sci Ltd, 2021) Ozarslan, Saliha; Atelge, M. Rasit; Kaya, Mustafa; Unalan, Sebahattin
    In this study, the catalyst produced from tea factory waste (TFW) was used for the first time for hydrogen production by methanolysis of sodium borohydride (NaBH4). The produced material had a dual function as both catalyst and supercapacitor; therefore, it was named 'cap-cat'(capacitor-catalyst) by us. In this context, TFW was treated with acetic acid for 24 h at 80 degrees C. The sample was then subjected to combustion in the oven to synthesize the catalyst. Afterward, the most efficient TFW-CH3COOH catalyst was synthesized by evaluating different acid ratios, burning temperatures and times. The best conditions for the acetic acid ratio, burning temperature, and time were found out 3 M, 300 degrees C, and 60 min. The characterization of the catalyst was done using SEM-EDX, FTIR, XRD analysis. Hydrogen generation experiments from NaBH4 by methanolysis were performed at various catalyst concentrations in the range of 0.05-0.2 g, diverse NaBH4 ratio of 1 to 7.5%, and at different reaction temperatures (30-60 degrees C). The HGR of the synthesized catalyst was recorded as 3096.4, 8367.5, 11227.9, and 23,507 mLmin(-1)g(cat)(-1) for these temperatures (30, 40, 50, and 60 degrees C), respectively. Also the activation energy was calculated as 38.6 kJ mol(-1). Subsequently, the CV (cyclic voltammetry) and charge-discharge curves of the prototypes produced were substantially similar to the supercapacitor curves in the literature. Gravimetric capacitance was found to be 155F/g at a current density of 2 A/g.
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    A REVIEW FOR ASSESSMENT METHODS OF BLACK TEA PRODUCTION WASTE
    (Begell House Inc., 2022) Ozarslan, Saliha; Rasit Atelge, M.; Kaya, Mustafa; Unalan, Sebahattin
    Tea production waste occurs during the production of black tea from fresh tea in tea factories, consisting of tea stalk, fiber, and powder, which are unused parts of the tea plant. Tea waste amounts may vary according to the quality of the production process and the harvesting of tea. However, a certain amount of tea waste is obtained every year in the countries that produce tea. Such a large and inexpensive biomass resource is not generally evaluated. There are several ways to take advantage of this biomass source and work on this subject is increasing. In this study, the methods of evaluating tea wastes were researched and the data obtained were transferred with their results. Studies collected under five main topics can be promising for the development of existing studies and new research. This study can be a guide for removing losses from the storage of tea waste and making this biomass economically valuable. © 2022 Begell House Inc.. All rights reserved.
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    Modeling and simulation of co-digestion performance with artificial neural network for prediction of methane production from tea factory waste with co-substrate of spent tea waste
    (Elsevier Sci Ltd, 2021) Ozarslan, Saliha; Abut, Serdar; Atelge, M. R.; Kaya, M.; Unalan, S.
    The production of biofuel from waste has become an important topic for waste management and reducing its environmental hazard. Tea factory waste is a strong candidate due to its availability and sourceability. This study aimed to reveal the biochemical methane potential (BMP) of tea factory waste (TFW) and spent tea waste (STW). Additionally, the results revealed that both substrates had high biodegradability due to high VS removal. The BMP tests took 49 days under mesophilic conditions with a batch reactor and the cumulative methane yields were 249 +/- 3, and 261 +/- 8 mL CH4/g VS for TFW and STW, respectively. According to prediction data with the selected ANN model, which was 50 hidden layer sizes, trained with Bayesian Regularization algorithm, the maximum cumulative specific methane yield of the co-digestion was simulated as 468.43 mL CH4/g VS when the ratio of 65 and 35% (w/w by VS) of TFW and STW, respectively. The predicted methane yield for co-substrates was 183% higher than mono substrates. This result revealed that TFW can be a good candidate for biogas production as biofuel for not only its availability and sourceability but also the synergistic effect possible for codigestion.
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    Production of dual functional carbon material from biomass treated with NaOH for supercapacitor and catalyst
    (Wiley, 2021) Ozarslan, Saliha; Atelge, Muhammed Rasit; Kaya, Mustafa; Unalan, Sebahattin
    In this research, tea factory waste (TFW), an organic biomass source, was used as a metal free basic catalyst for the production of hydrogen from NaBH4 by methanolysis. In the preparation of the catalysts, tea factory wastes taken from the tea factory and released during tea production were used. For the production of H-2 from NaBH4 by methanolysis, TFW was pre-treated with different base materials (KOH, NH4Cl, and NaOH). Tests have been made on different mixing ratios, combustion temperatures, and durations for catalyst optimization by selecting the base with the highest hydrogen yield. Hydrogen production efficiency was recorded as 2832.2 and 6560.8 mL min(-1) g(-1) at 30 degrees C and 60 degrees C, respectively. The activation energy of the catalyst was defined as 18.07 kJ mol(-1). Characterization of TFW catalyst was examined by SEM-EDX, XRD, and FT-IR analysis. When the obtained data were evaluated and some studies available in the literature were considered, it was concluded that tea factory wastes, which are a biomass resource, can be used in catalyst production. The capacitance value of the electrode was computed as 8 to 12.9 F g(-1).