Degradation of acid red 97 dye in aqueous medium using wet oxidation and electro-Fenton techniques
Gözmen Belgin | Gizir, Ahmet Murat
Degradation of the acid red 97 dye using wet oxidation, by different oxidants, and electro-Fenton systems was investigated in this study. The oxidation effect of different oxidants such as molecular oxygen, periodate, persulfate, bromate, and hydrogen peroxide in wet oxidation system was compared. Mineralization of AR97 with periodate appeared more effective when compared with that of the other oxidants at equal initial concentration. When 5 mM of periodate was used, at the first minute of the oxidative treatment, the decolorization percentage of AR97 solution at 150 and 200 °C reached 88 and 98%, respectively. The total organic carbon removal efficiency at these temperatures also reached 60 and 80%. The degradation of AR97 was also studied by electro-Fenton process. The optimal current va...
Oxidative degradations of reactive blue 4 dye by different advanced oxidation methods
Gözmen Belgin | Gizir Ahmet Murat
The degradations of an anthraquinone dye, the reactive blue 4 (RB4), were studied by wet air oxidation (WAO), wet peroxide oxidation (WPO), photocatalytic oxidation, and electro-Fenton (EF) advanced oxidation. The RB4 oxidation was evaluated by the decrease in total organic carbon (TOC) content and concentration. The most efficient method for mineralization of RB4 was WPO, but in all methods TOC removal efficiency was above 75% after 60 min of treatment.
The solubility of sebacic acid in subcritical water using the response surface methodology
Gözmen, Belgin | Görmez, Özkan | Yabalak, Erdal | Gizir, Ahmet Murat
The solubility of sebacic acid in subcritical water was investigated. Response surface methodology was used to study the combined effects of the different parameters such as temperature, static and dynamic time to optimize the process conditions for the maximum solubility of sebacic acid. Solubility results of sebacic acid were observed to be highly correlated with quadratic model according to analysis of variance. The solubility of sebacic acid was found as 500 g L-1 in the optimum conditions at 400 K temperature, 4 min dynamic time and 28 min static time. Approximation models were employed for determining solubility of sebacic acid at elevated temperatures.
Degradation of nitroaromatic compounds in subcritical water: application of response surface methodology
Gözmen, Belgin | Gizir, Ahmet Murat
In this study, subcritical water has been used as a medium for degradation of 2,4-dinitrotoluene (2,4-DNT), 4-nitrotoluene (4-NT) and 2-amino-4-nitrotoluene (2-A-4-NT). The effect of temperature, oxidant concentration and time were studied and the optimal combination of reaction parameters was established using response surface methodology in a Box-Behnken design. Of all the parameters examined, temperature showed the most positive effect on the degradation of the nitroaromatic compounds. Optimal reaction conditions were found to be a temperature of 240°C, 210°C and 236°C, time of 180, 178 and 172 min, oxidant concentration of 100, 99.64 and 99.61 mM for 2,4-DNT, 4-NT and 2-A-4-NT, respectively. Since high-temperature was applied, the possibility of formation of subcritical degradat...