Yeliz Aşçı - Academia.edu (original) (raw)

Papers by Yeliz Aşçı

DESALINATION AND WATER TREATMENT, Dec 31, 2022

Fresenius Environmental Bulletin, 2018

Eskişehir technical university journal of science and technology a- applied sciences and engineering, Sep 30, 2020

Nowadays, leaving industrial wastewater into receiving environment causes serious environmental p... more Nowadays, leaving industrial wastewater into receiving environment causes serious environmental problems. In this study, experimental studies on color and chemical oxygen demand (COD) removal of paper industrial wastewater were carried out. In this context, heterogeneous Fenton and photocatalytic oxidation processes were applied and removal efficiencies were compared. The Fe(III)/MnO2 catalyst containing 8% w/w of iron ion was synthesized to be used in experimental studies. The effects of parameters such as pH, catalyst amount, hydrogen peroxide concentration and reaction time were investigated. At the end of the experimental studies, 90% color and 55% COD removal efficiencies were obtained in heterogeneous Fenton process after 120 minutes reaction time under optimum conditions. After 60 minutes reaction time under the same optimum conditions, 97% color and 91% COD removal efficiencies were achieved in photocatalytic oxidation process.

Iğdır üniversitesi fen bilimleri enstitüsü dergisi, Apr 24, 2017

Cr(III), çeşitli endüstriyel atıksularda var olan toksik ağır metallerden biridir. Bu çalışmada s... more Cr(III), çeşitli endüstriyel atıksularda var olan toksik ağır metallerden biridir. Bu çalışmada sulu çözeltilerden krom giderimi iyon değişimi yöntemiyle araştırılmıştır. Bu amaçla sorbent olarak güçlü bir katyon değiştirici reçine olan Dowex 88 kullanılmıştır. Deneysel çalışmalarda pH, sıcaklık, reçine miktarı ve sorpsiyon süresi gibi parametrelerin krom giderimine etkisi incelenmiştir. Ayrıca, termodinamik, izoterm ve kinetik çalışmalar yapılmıştır. İzoterm çalışmalarında Langmuir ve Freundlich izoterm modelleri denenmiş ve deneysel verilerin her iki izoterm modeline de uyduğu görülmüştür. Termodinamik sonuçlar, Dowex 88 reçinesine krom sorpsiyonunun ekzotermik ve kendiliğinden gerçekleştiğini göstermiştir. Kinetik çalışmalar sonucunda ise sorpsiyon verilerinin tersinir birinci mertebe kinetik modele uyduğu gözlenmiştir.

Eskişehir Osmangazi Üniversitesi Mühendislik ve Mimarlık Fakültesi Dergisi, 2021

The unconscious use of surface and ground waters and the rapid pollution of water, which is the m... more The unconscious use of surface and ground waters and the rapid pollution of water, which is the main source of life for all living creatures as a result of drought due to global warming, pose a serious problem. The rapidly increasing world population and the need for clean water have brought up a global water crisis. The textile industry is one of the largest producers of wastewater in the world. Textile industry wastewater contains high amounts of non-biodegradable organic compounds, high concentrations of dyestuffs, salt, detergent and soap. Therefore, it is of great importance to remove organic pollutants in this wastewater. Since traditional methods are insufficient to remove organic compounds in wastewater, advanced treatment methods are required. Advanced oxidation processes (AOPs) are one of the alternative treatment methods preferred in recent years. In this study, color removal from textile industry wastewater was researched by the heterogeneous Fenton process, which is an ...

DESALINATION AND WATER TREATMENT

In this study, decolorization of the synthetic wastewater containing Reactive Yellow 15 (RY15) by... more In this study, decolorization of the synthetic wastewater containing Reactive Yellow 15 (RY15) by means of the heterogeneous Fenton process was investigated. Primarily, the Fe/CuO catalyst was prepared by co-precipitation method and characterized by BET and SEM-EDX analyses. The prepared catalyst was used in the Fenton tests. The effects of the amount of the catalyst, pH of the solution, hydrogen peroxide (H2O2) concentration, dye concentration, temperature and reaction time on the process were studied and the optimum conditions were determined. The decolorization efficiency of 98% was obtained under the optimum conditions (pH = 2, amount of catalyst = 4.0 g/L, temperature = 30°C, H2O2 concentration = 50 mM, time = 60 min). The decolorization kinetics of RY15 was also investigated. It was determined that the decolorization of RY15 obeyed the zero-order kinetics. Finally, reusability of the catalyst was investigated. The results show that the Fe/CuO catalyst is useful for the heterog...

Desalination and Water Treatment

Cobalt is a toxic heavy metal found in various industrial wastewaters. In this study, the sorptio... more Cobalt is a toxic heavy metal found in various industrial wastewaters. In this study, the sorption mechanisms of Co(II) onto Amberlite 200C and Dowex 88 resins were investigated using batch reactors. The removal of Co(II) was examined by varying experimental conditions, such as the solution pH, sorbent dose, and temperature. The most effective pH range for cobalt removal was pH 4-8 for both resins. Langmuir, Freundlich, Redlich-Peterson, and Temkin models were applied to describe equilibrium isotherms. The sorption of Co(II) on the resins followed pseudo-second-order kinetics, and thermodynamic data indicated an endothermic and spontaneous process. ΔG˚decreased with increasing temperature, indicating that the sorption process of Co(II) on both resins was more favorable at high temperatures. Desorption studies were conducted using various reagents. For both resins, the maximum percent of metal ion desorption was reached when 2 M H 2 SO 4 was used as the reagent.

Desalination and Water Treatment, 2015

The treatment of aviation industry metal plating wastewater containing Ni 2+ and Cr 6+ by nanofil... more The treatment of aviation industry metal plating wastewater containing Ni 2+ and Cr 6+ by nanofiltration was investigated in this study. Two commercial membranes (NF90 and NF270) and two membrane filtration systems (dead end and cross flow) were used. The effects of both the transmembrane pressure (10, 20, and 30 bar) and the feed pH (3.5, 7, and 10) on the membrane performance were analyzed. The rejection of both nickel and chromium ions increased with increasing pH but did not considerably change by the pressure difference for both membranes. The optimum conditions were found to be at 30 bar with a pH of 10 for both the NF90 and NF270 membranes. Under optimum conditions for the NF90 membrane, the rejection values of Ni 2+ and Cr 6+ were found to be 99.2 and 96.5%, respectively. For the NF270 membrane, the rejection values of Ni 2+ and Cr 6+ were 98.7 and 95.7%, respectively.

Desalination and water treatment

In the present work, the removal of Co(II) ions from aqueous solutions using an ion-exchange resi... more In the present work, the removal of Co(II) ions from aqueous solutions using an ion-exchange resin (Lewatit MonoPlus SP 112) was investigated. For this purpose, batch adsorption studies were carried out with various parameters such as pH and contact time. The Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Langmuir isotherm and the maximum adsorption capacity was found to be 21.93 mg/g. The kinetic data were tested using pseudo-first-order, pseudo-second-order, liquid film diffusion, and intraparticle diffusion kinetic models. In addition, diffusion models were applied to explore the rate-determining step in cobalt diffusion behavior. The numerical values of the different rate constants, correlation coefficients, and effective diffusion coefficients as well as activation energy were determined. Data clarified that the adsorption process followed pseudo-second order reaction-base...

Journal of the Institute of Science and Technology

Journal of Hazardous Materials, 2007

In this study, a microbial surfactant, rhamnolipid, was investigated for its potential to enhance... more In this study, a microbial surfactant, rhamnolipid, was investigated for its potential to enhance recovery of Cd(II) from kaolin, a representative soil component. The study was divided into two parts. In the first part, the sorption of Cd(II) ions to kaolin was investigated as a function of pH and initial Cd(II) ion concentration. Kaolin was also shown to be a good sorbent for treatment of Cd(II) ions from waste waters. The equilibrium sorption capacity for Cd(II) ions was measured and extrapolated using the Langmuir, Freundlich, Redlich-Peterson, and Koble-Corrigan sorption models. The best correlation between experimental and model predicted equilibrium uptake was obtained using the Kolbe-Corrigan sorption model. The values of parameters of the Koble-Corrigan model were determined as A = 11.13 (mmol 1−b kg −1 L b); B = 0.39 (L b mmol −b); b = 0.48. In the second part, the desorption of Cd(II) from kaolin was investigated as a function of pH, rhamnolipid concentration, and the amount of sorbed Cd(II) by kaolin. The highest Cd(II) desorption efficiency by rhamnolipid biosurfactant from kaolin was obtained at pH 6.8, at an initial Cd(II) ion concentration of 0.87 mM (4.42 mmol Cd(II)/kg kaolin) and at a rhamnolipid concentration of 80 mM and found to be 71.9% of the sorbed Cd(II).

Journal of Hazardous Materials, 2008

Recent research has demonstrated that biosurfactants, especially rhamnolipids, can enhance recove... more Recent research has demonstrated that biosurfactants, especially rhamnolipids, can enhance recovery of soil-bound metals. To propose the success of remediation process of soils by rhamnolipids, both sorption and desorption characteristics of soils having different clay mineralogy should be known exactly. To assess sorption of Cd(II), batch equilibrium experiments were performed using three soils characterized with different proportions of clay minerals from Eskişehir region of Turkey. Soil pH, initial metal concentration and clay mineralogy affected the sorption process. For comparisons between soils, the sorption process was characterized using the Langmuir, Freundlich, Redlich-Peterson, Koble-Corrigan sorption models. The Freundlich model showed the best fit for the Cd(II) sorption data by the soils, while the Langmuir-type models generally failed to describe the sorption data. Soils with higher clay content characterized by having smectite as a dominant component had the greatest sorption capacity and intensity estimated by the K F and n parameters of the Freundlich model. The soil C has the highest sorption efficiency of 83.9%, followed by soils B and A with sorption efficiencies of 76.7% and 57.9%, respectively. After the soils were loaded by different doses of Cd(II), batch washing experiments were used to evaluate the feasibility of using rhamnolipid biosurfactant for the recovery of Cd(II) from the soils. The Cd(II) recovery of the soils were investigated as a function of pH, amount of Cd(II) loaded to the soils, and rhamnolipid concentration. Cd(II) recovery efficiencies from the soils using rhamnolipid biosurfactant decreased in the order of soil A > soil B > soil C. This order was the reverse of the Cd(II) sorption efficiency order on the soils. When 80 mM rhamnolipid was used, the recovery efficiencies of Cd(II) from the soils A, B, and C was found to be 52.9%, 47.7%, 45.5% of the sorbed Cd(II), respectively. Rhamnolipid sorption capacity of the soils in the presence of Cd(II) ions decreased in the order of soil A > soil B > soil C.

Journal of Environmental Management, 2010

In the present study, the sorption characteristics of Cd(II) and Zn(II) ions on quartz, a represe... more In the present study, the sorption characteristics of Cd(II) and Zn(II) ions on quartz, a representative soilcomponent, and the desorption of these metal ions from quartz using rhamnolipid biosurfactant were investigated. In the first part of the studies, the effects of initial metal ion concentration and pH on sorption of Cd(II) and Zn(II) ions by a fixed amount of quartz (1.5 g) were studied in laboratory batch mode. The equilibrium sorption capacity for Cd(II) and Zn(II) ions was measured and the best correlation between experimental and model predicted equilibrium uptake was obtained using the Freundlich model. Although investigations on the desorption of heavy metal ions from the main soil-components are crucial to better understand the mobility and bioavailability of metals in the environment, studies on the description of desorption equilibrium were performed rarely. In the second part, the desorption of Cd(II) and Zn(II) from quartz using rhamnolipid biosurfactant was investigated as a function of pH, rhamnolipid concentration, and the amounts of sorbed Cd(II) and Zn(II) ions by quartz. The Freundlich model was also well fitted to the obtained desorption isotherms. Several indexes were calculated based on the differences of the quantity of Cd-Zn sorbed and desorbed. A desorption hysteresis (irreversibility) index based on the Freundlich exponent, concentration-dependent metal distribution coefficients, and the irreversibility index based on the metal distribution coefficient were used to quantify hysteretic behavior observed in the systems.

Journal of Environmental Management, 2008

This study investigated the sorption characteristics and recovery of selected heavy metal Cd(II) ... more This study investigated the sorption characteristics and recovery of selected heavy metal Cd(II) from K-feldspar and sepiolite, representative soil components, using rhamnolipid biosurfactant. Although the proposed technique was classified as a soil bioremediation process, it can also be applied to treatment of waste waters containing Cd(II) ions with minor modifications. The effect of initial Cd(II) concentration on sorption capacity was characterized by determining the sorption isotherms. Of the four models examined, the Freundlich model showed the best fit for the sorption of Cd(II) on K-feldspar, whereas the Langmuir-model was used successfully to characterize the sorption of Cd(II) on sepiolite. Although a high Cd(II) uptake of 7.49 mmol/kg by K-feldspar was obtained, sepiolite was a superior Cd(II) accumulater, with a maximum Cd(II) uptake of 24.66 mmol Cd(II)/kg. The presence of Cd(II) in the sepiolite or K-feldspar prior to addition of the rhamnolipid generally resulted in less rhamnolipid sorption to sepiolite or K-feldspar. The maximum Cd(II) desorption efficiency by rhamnolipid from K-feldspar was substantially higher than that of sepiolite and determined to be 96% of the sorbed Cd(II), whereas only 10.1% of the sorbed Cd(II) from sepiolite was recovered by rhamnolipid solution.