Comparative mineralization of Basic Red 18 with electrochemical advanced oxidation processes
Gözmen, Belgin | Sönmez, Özgür
In this study, the role of electrochemical oxidation processes, including the electro-Fenton, the electro-persulfate (PS), and the electro/FeII /PS processes, in the removal of Basic Red 18 (BR18) from aqueous solutions was investigated. It was found that the electro-PS process successfully removes colour, but after 5 h, it produced only 75 % mineralization. In the same conditions, more effective mineralization was achieved by the electro/FeII/PS process than by the electro-Fenton method. At pH levels of 3.0 and 5.7, very effective mineralization results were produced by the electro/FeII/PS process. Moreover, the maximum mineralization current efficiency values were obtained by the electro/FeII/PS process. The mineralization efficiency of the electro/FeII/PS process was determined to ...
Evaluation of sewage sludge biochar and modified derivatives as novel SPE adsorbents for monitoring of bisphenol A
Gözmen, Belgin | Sönmez, Özgür
Sewage sludge is abundant biomass, the sustainable management of which remains a big issue worldwide. It was demonstrated that pyrolysis of sewage sludge using simple and cost-effective apparatus can produce biochars, suitable for solid-phase extraction applications of hydrophobic analytes. Detailed characterization showed that modification lead to three more hydrophobic and one more hydrophilic sample, compared to the original biochar. All samples were evaluated in the solid-phase extraction of the emerging contaminant Bisphenol A from aqueous solutions. KOH-SSB and KOH/MeOH-SSB exhibited the most promising behavior, with the latter achieving recoveries of 88.1%, at a quantity of 0.1 g at the natural pH of the BPA solution (6.5). The effect of solution pH was insignificant in the range of...
Esterification of oleic acid using CoFe2O4@MoS2 solid acid catalyst under microwave irradiation
Sönmez, Özgür | Gözmen, Belgin
Ensuring highly efficient biodiesel production requires catalysts. Therefore, developing heterogeneous catalysts capable of being recovered and reused without compromising effectiveness is crucial. In this context, the CoFe2O4@MoS2 heterogeneous magnetic acid catalyst was synthesized and characterized in detail by XRD, SEM-EDX, BET surface area, magnetic property and acid strength. Finally, the catalytic performance of this catalyst was evaluated for the esterification of oleic acid by microwave-assisted method. The fabricated CoFe2O4@MoS2 catalyst has a strong saturation magnetization of 15.78 emu/g, a surface area of 6.70 m2/g, and a high acid loading of 2.1 mmol H+/g, according to the characterization data. The highest oleic acid conversion of 98.2 % was achieved under the optimum condi...
Microwave-assisted d-pinitol extraction from carob: application of Box–Behnken design
Gözmen, Belgin | Sönmez, Özgür
This study investigates the effects of temperature (50–80 °C), time (10–60 min), carob-to-solvent ratio (2–8 g/40 mL), and solvent concentration (0–50 ethanol/water%, v/v) on microwave-assisted extraction of d-pinitol compound from carob fruit with optimization using Box–Behnken design. The optimal conditions for maximum d-pinitol yield (64.16 g/kg dry sample) include 50 °C temperature, 5.6 g carob/40 mL solvent, water used as a solvent, and an extraction time of 10 min. The fitness of the model was determined by ANOVA analysis with a high coefficient (R2 = 0.9057). Extraction was performed under optimum conditions for model validation, and 63.89 g/kg dry sample of d-pinitol extraction was achieved. In addition, the effects of the same variables on the total phenolic (TP) content of MEA ex...
Microwave-assisted biodiesel production from waste cooking oil using pyrrolidonium ionic liquid catalyst: optimization, kinetic and thermodynamic studies
Gözmen, Belgin | Sönmez, Özgür
Biodiesel production from waste cooking oil (WCO) has been gaining popularity due to its economical and eco-friendly nature. This study aimed to produce an environmentally friendly fuel by recycling WCO. Using pyrrolidonium-based Brønsted acidic ionic liquid (IL) as a catalyst, microwave-assisted transesterification of WCO was used to produce biodiesel. Reaction conditions, including temperature, catalyst amount, methanol/oil molar ratio, and reaction time, were optimized using response surface methodology (RSM) based on Box-Behnken design (BBD). A biodiesel conversion of 97.3 % was achieved at 115 °C, for 120 min, with 10 % catalyst loading, and a 24:1 methanol/oil molar ratio. The kinetics of the transesterification reaction was investigated, with the activation energy determined to be 1...
Influence of the addition of various ionic liquids on coal extraction with NMP
Sönmez, Özgür | Gözmen, Belgin
In this work, two Turkish coals were extracted with N-methyl-2-pyrrolidone (NMP) and NMP containing a small amount of ionic liquids (ILs) under reflux conditions at atmospheric pressure. The effects of coal type, ionic liquid type, ionic liquid-to-coal ratio, and ultrasonic interactions on extraction yield were investigated. The ILs used were: 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), 1-buty-4- methylpyridinium chloride ([Bmp]Cl), 1-ethyl-3-methylimidazolium chloride ([Emim]Cl), and 1-butyl-2,3-dimethylimidazolium chloride ([Bdmim]Cl). It was found that the extraction yield of coals using NMP/ILs varied with coal type, IL type and amount of IL. ILs were effective on the extraction of Afsin-Elbistan (AE) lignite, but not on the extraction of Üzülmez (UZ) coal. A significant in...
Optimization of solvent extraction process of some Turkish coals using response surface methodology and production of ash-free coal
Gözmen, Belgin | Sönmez, Özgür
In order to produce ash-free coal (AFC) from three Turkish coals, solvent extraction of coals using 1-methylnaphthalene (1-MN) at different temperatures were conducted. The extraction yield of coals was found dependenton coal, temperature, and solvent type. When there was usage of 1-MN as solvent, the extraction yield was low. However,on addition of N-methyl-2-pyryrolidone (NMP) or quinoline (QN) into 1-MN, the extraction yield increased. Following theextractions, we obtained AFC with less than 0.65% ash content for the three coals used in this study. The response surfacemethodology (RSM) was employed to investigate the solvent extraction conditions. The factors investigated were extractiontemperature and additional polar solvent ratio. The obtained results demonstrated that either excess ...