Sibel Barışçı

An evaluation on different origins of natural organic matters using various anodes by electrocoagulation.

In this investigation, natural organic matters (NOM) of different origins (commercial, terrestrial and natural water) were treated by electrocoagulation (EC) process using aluminum, iron and hybrid electrodes. Electrode type effect on removal efficiency was observed for each NOM (commercial, terrestrial, and natural). The results were presented as dissolved organic carbon (DOC) (mg L(-1)) and UV/VIS absorbance (cm(-1)). The specific UV absorbance (SUVA) was determined before and after treatment of water. The lowest effluent concentration was obtained as 5.05 mg L(-1) with hybrid electrode for natural NOM source at its original pH 7.3. In addition, among the metal types, the best UV-abs-254 removal efficiency was obtained as 92.4% with 0.0312 cm(-1) by hybrid electrode at the end of the process. The color removal efficiency of water occurred successfully by Al and hybrid electrodes. Aquatic NOM source was the most resistant to EC treatment with DOC reduction of 71.1%, 59.8%, and 68.6% for Al, Fe and hybrid electrodes, respectively. Zeta potential and floc size of colloids were observed during the process for the determination of destabilization level of natural organic matters in EC process. Fast coagulation or flocculation and incipient instability were formed during electrolysis time for Al and Fe electrode, respectively. SUVA value was reduced to below 2 for three NOM sources studied. The EC process was shown to be a viable for different NOM sources with various metals.

The Disposal of Combed Cotton Wastes by Pyrolysis

The main objective of this work is to propose an alternative method for disposing of combed cotton wastes consisting of swatches with various sizes and shapes. For this purpose, pyrolysis of combed cotton waste was conducted in a fixed bed reactor with the final temperatures of 450, 500, 550, and 600°C. Effect of the experimental conditions such as temperature, catalyst type on the formation of liquid, gas, and char products were investigated and product yields were measured. The highest liquid product efficiency was achieved with 29.74% at the temperature of 550°C. CaCO3 and Na2CO3 were used as catalysts. Na2CO3 was found to be more effective catalyst than CaCO3 The properties of the obtained liquid product were analyzed by high performance liquid chromatography (HPLC). Furans, ketones, aldehydes, less carboxylic acids, and hydrocarbons were detected in the content of liquid product. The calorific values of raw material, liquid product, and char were also determined by using IKA C 200 calorimeter. The results clearly indicated that both temperature and catalyst type affect the formation of liquid product. Pyrolysis may be a useful way of waste management for energy and material recovery.

Optimization and modelling using the response surface methodology (RSM) for ciprofloxacin removal by electrocoagulation.

In this study, response surface methodology (RSM) was used to investigate the effects of different operating conditions on the removal of ciprofloxacin (CIP) by the electrocoagulation (EC) with pure iron electrodes. Box-Behnken design was used for the optimization of the EC process and to evaluate the effects and interactions of process variables such as applied current density, process time, initial CIP concentration and pH on the removal of CIP by the EC process. The optimum conditions for maximum CIP removal (86.6%) were found as pH = 4; Co = 5 mg.L(1-); Id = 4.325 mA.cm(2-); tprocess = 10 min. The model adequacy and the validity of the optimization step were confirmed with additional experiments which were performed under the proposed optimum conditions. The predicted CIP removal as 86.6% was achieved at each experiment by using the optimum conditions. These results specify that the RSM is a useful tool for optimizing the operational conditions for CIP removal by the EC process.

Electrochemical treatment of anti-cancer drug carboplatin on mixed-metal oxides and boron doped diamond electrodes: Density functional theory modelling and toxicity evaluation

This study represents the electrooxidation of anti-cancer drug carboplatin (CrbPt) with different mixed metal oxide (MMO) and boron doped diamond (BDD) electrodes. The most effective anode was found as Ti/RuO2 with the complete degradation of CrbPt in just 5min. The effect of applied current density, pH and electrolyte concentration on CrbPt degradation has been studied. The degradation of CrbPt significantly increased at the initial stages of the process with increasing current density. However, further increase in current density did not affect the degradation rate. While complete degradation of CrbPt was provided at pH 7, the degradation rates were 49% and 75% at pH 9 and 4, respectively. Besides, increasing supporting electrolyte (Na2SO4) concentration provided higher degradation rate but further increase in Na2SO4 concentration did not provide higher degradation rate due to excess amount of SO4-2. According to the DFT calculations, the formation of [Pt(NH3)2 (H2O)2]2+ and [Pt(NH3)2 (OH)2] takes place with molecular weights of 265 and 263gmol-1, respectively. Toxicity of treated samples at BDD and Ti/RuO2 electrodes has been also evaluated in this study. The results showed that Ti/RuO2 anode provided zero toxicity at the end of the process.

Degradation of Toxic Indigo Carmine Dye by Electrosynthesized Ferrate (VI)

Response surface methodology was applied for optimizing indigo carmine (IC) dye removal by electrochemically produced ferrate (VI). Box-Behnken design was employed in this study, and design parameters were pH, Fe (VI) dose and initial dye concentration (C o ). R 2 and adjusted R 2 values were very high that indicated very good accuracy for the employed model. Optimum operational conditions were: 4.08-7.69 for pH, 24-118.83 mg/L for Fe (VI) dose and 60.68-99.13 mg/L for complete removal of IC. Produced by electrochemical method Ferrate (VI) provides high effectiveness for IC dye-containing synthetic wastewater.