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Assessing effect of electrode configuration on the efficiency of electrokinetic remediation by sequential extraction analysis

Türer, Dilek | Genç, Ayten

Article | 2005 | JOURNAL OF HAZARDOUS MATERIALS119 ( 01.Mar ) , pp.167 - 174

The electroremediation experiments were conducted on artificially polluted soils by introducing a single metallic contaminant (Pb, Zn and Cu) and multiple metallic contaminants (Pb + Zn + Cu). Based on sequential extraction results, it was observed that the removal efficiencies of lead, zinc and copper vary depending on types of contamination. When the soil was contaminated only by lead, the removal efficiency was found to be 48%. However, the removal efficiency of lead decreased to 32% when the soil was contaminated by the combination of lead, zinc and copper. Similar results were observed for zinc and copper. The corresponding rem . . .oval efficiency values for zinc and copper were 92% and 37%, and 34% and 31%, respectively. Effects of electrode geometry on the removal efficiency of metals were investigated by constructing a multiple anode arrangement. In this arrangement, the electrokinetic unit consists of three cylinders, which lie one inside the other, and the soil was placed in the middle cylinder. The central cylinder was the cathode well and the outer cylinder was the anode well, where eight identical anode electrodes were placed in octagonal with respect to the cathode electrode. By using this electrode arrangement in removal of metals from the soil contaminated with the combination of three metals (Pb + Zn + Cu), the removal efficiencies of lead, zinc and copper were found to be 29%, 18% and 18%, respectively. As it can be seen, these numerical values are much lower than the values that were obtained when the traditional two-plate electrode arrangement used in the electroremediation experiments (32%, 37% and 31%). (c) 2004 Elsevier B.V. All rights reserved Daha fazlası Daha az

Treatment of emulsified oils by electrocoagulation: Pulsed voltage applications

Genç, Ayten | Bakırcı, Büşra

Article | 2015 | Water Science and Technology71 ( 8 ) , pp.1196 - 1202

The effect of pulsed voltage application on energy consumption during electrocoagulation was investigated. Three voltage profiles having the same arithmetic average with respect to time were applied to the electrodes. The specific energy consumption for these profiles were evaluated and analyzed together with oil removal efficiencies. The effects of applied voltages, electrode materials, electrode configurations, and pH on oil removal efficiency were determined. Electrocoagulation experiments were performed by using synthetic and real wastewater samples. The pulsed voltages saved energy during the electrocoagulation process. In cont . . .inuous operation, energy saving was as high as 48%. Aluminum electrodes used for the treatment of emulsified oils resulted in higher oil removal efficiencies in comparison with stainless steel and iron electrodes. When the electrodes gap was less than 1 cm, higher oil removal efficiencies were obtained. The highest oil removal efficiencies were 95% and 35% for the batch and continuous operating modes, respectively. © IWA Publishing 2015 Daha fazlası Daha az

Experimental studies on the effect of electrode configuration in electrofiltration

Genç, Ayten | Tosun, İbrahim

Article | 2002 | Separation Science and Technology37 ( 13 ) , pp.3053 - 3064

Results from the electrofiltration of anatase (TiO2) particles in a water suspension and using three different electrode configurations are presented. The three electrode configurations studied were spot, foil, and mesh. For the first two configurations, the electric field was perpendicular to the direction of flow while for the mesh configuration it was opposite to the direction of flow. The percent gain volume filtrate and power consumption were measured for each electrode configuration. For a given percent gain volume filtrate, it was observed that the foil electrode configuration consumes the least power.

Membrane potentials for linearly varying fixed charges

Genç, Ayten

Article | 2009 | Turkish Journal of Engineering and Environmental Sciences33 ( 1 ) , pp.73 - 81

The membrane potentials for asymmetric membranes where fixed charges varied linearly with position were evaluated from the numerical solutions of Nernst-Planck flux and Donnan potential equations. The evaluated membrane potentials were compared with the results obtained from the conventional TMS theory where the fixed charge concentration in the membrane was assumed to be uniform. In the comparison, the number of fixed charges was kept constant by defining an average for the fixed charge concentration. The numerical results showed that the membrane potential increased in magnitude when the distributions of fixed charges at the membr . . .ane-solution interfaces were unequal. In addition, the deviation from TMS theory increased more as the charge difference at the interfaces increased. © TÜBİTAK Daha fazlası Daha az

Analysis of the electrofiltration mechanism based on multiphase filtration theory

Genç, Ayten | Tosun, İsmail

Article | 2004 | Chemical Engineering Communications191 ( 1 ) , pp.125 - 136

A mathematical model based on multiphase filtration theory is developed to describe the electrofiltration process. The model takes both electrophoretic and electroosmotic effects into account. The electrophoretic migration velocity of solid particles is predicted from the model using the filtrate volume time data obtained from electrofiltration experiments.

Destabilization and treatment of emulsified oils in wastewaters by electrocoagulation

Genç, Ayten | Bakırcı, Büşra

Article | 2016 | Water Environment Research88 ( 11 ) , pp.2008 - 2014

In this study, the optimum operating conditions for the treatment of emulsified oils by electrocoagulation were determined depending on droplet stability analysis. Zeta potential measurements were used as the indication of oil droplet charges. In addition, the effects of pH and ionic conductivity on the droplet sizes and surface charges were investigated. The studied emulsified oil droplet sizes were more sensitive to changes in pH rather than salt concentration. The droplets became larger and unstable in alkaline conditions. As the initial pH of wastewaters increased, the oil removal efficiency increased during the electrocoagulati . . .on experiments as well. The use of iron or aluminum electrodes resulted in higher removal efficiencies in comparison to stainless steel electrodes. In addition, the energy consumption for aluminum electrodes was much lower than iron electrodes. To obtain 98% oil removal efficiency, distance between the electrodes was recommended to be less than or equal to 1 cm. © 2016, Water Environment Federation. All rights reserved Daha fazlası Daha az

Sorption of acid dyes from aqueous solution by using non-ground ash and slag

Genç, Ayten | Oğuz, Aşkın

Article | 2010 | Desalination264 ( 01.Feb ) , pp.78 - 83

The sorption of two acid dyes (Acid Yellow 99 and Acid Red 183) into locally available industrial waste materials, namely, Granulated Blast Furnace Slag (GBFS) and Furnace Bottom Ash (FBA), has been investigated by performing batch equilibrium experiments with pH, ionic conductivity, initial dye concentration and temperature as variables. The kinetic sorption data indicated that the sorption capacity of GBFS for these dyes was almost zero. On the other hand, the color removal efficiency for FBA could reach 50% depending on the initial dye concentration. It was also found that the kinetics of sorption of Acid Yellow 99 and Acid Red 1 . . .83 onto the surface of FBA at different operating conditions were best described by the Elovich kinetic model. In addition, the adsorption equilibrium data were analyzed using various adsorption isotherm models and the results have shown that the sorption behaviors of the studied dyes could be best described by the Langmuir model. © 2010 Elsevier B.V Daha fazlası Daha az

Transport of Lead (Pb2+) Ions through silty-clayey soils under acidic conditions

Genç, Ayten | Ulupınar, Elif

Article | 2010 | Transport in Porous Media84 ( 3 ) , pp.699 - 709

This study aimed to identify effects of pH on the transport of Pb2+ ions through a saturated silty-clayey soil layer by using advection-dispersion equation (ADE). The predictive accuracy of the solution of ADE depends on the proper determination of the retardation by adsorption and, therefore, the adsorption mechanism of lead onto silty-clayey soil was investigated first by performing batch equilibrium experiments. These results showed that the sorption mechanism of lead onto silty-clayey soil depended on pH and could be best described by the Langmuir isotherm. Based on the results of the sequential experiments, it was also conclude . . .d that the pH dependent charges in silty-clayey soil were mainly associated with the surfaces of carbonates and the specific adsorption of lead ions. The numerical solutions of the combined form of ADE with the Langmuir isotherm indicated that the migration profiles of lead in silty-clayey soil were a strong function of the parameters of the Langmuir isotherm rather than the infiltration velocity. © 2010 Springer Science+Business Media B.V Daha fazlası Daha az

Prediction of the bottom ash formed in a coal-fired power plant using artificial neural networks

Bekat, Tuğçe | Erdoğan, Muharrem | İnal, Fikret | Genç, Ayten

Article | 2012 | Energy45 ( 1 ) , pp.882 - 887

The amount of bottom ash formed in a pulverized coal-fired power plant was predicted by artificial neural network modeling using one-year operating data of the plant and the properties of the coals processed. The model output was defined as the ratio of amount of bottom ash produced to amount of coal burned (Bottom ash/Coal burned). The input parameters were the moisture contents, ash contents and lower heating values of the coals. The total 653 data were divided into two groups for the training (90% of the data) and the testing (10% of the data) of the network. A three-layer, feed-forward type network architecture with back-propaga . . .tion learning was used in the modeling study. The activation function was sigmoid function. The best prediction performance was obtained for a one hidden layer network with 29 neurons. The learning rate and the tolerance value were 0.2 and 0.05, respectively. R2 (coefficient of determination) values between the actual (Bottom ash/Coal burned) ratios and the model predictions were 0.988 for the training set and 0.984 for the testing set. In addition, the sensitivity analysis indicated that the ash content of coals was the most effective parameter for the prediction of the ratio of bottom ash to coal burned. © 2012 Elsevier Ltd Daha fazlası Daha az

Effects of coal properties on the production rate of combustion solid residue

Durgun D. | Genç, Ayten

Article | 2009 | Energy34 ( 11 ) , pp.1976 - 1979

The production rates of furnace bottom ash in a pulverized coal-fired power plant were monitored for a two-year period and its variations with respect to coal properties were analyzed. The power plant was originally designed to fire the coal sludge generated from a washing process; however, the coal sludge and its mixture with low-rank bituminous coal have been started to be used as the main fuel with time. The results of the hardgrove grindability measurements have shown that the grinding properties of sludge or its mixtures could not be predicted based on proximate analysis (moisture, ash, carbon and volatile contents); it could o . . .nly be determined by experiments. The production rate of bottom ash in this particular power plant remained relatively insensitive to the high ash and moisture contents and could be estimated almost only by knowing the calorific value of the source coal. The evaluated dependency was linear. © 2009 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Cost analysis of plastic solid waste recycling in an urban district in Turkey

Genç, Ayten | Zeydan, Özgür | Saraç, Selin

Article | 2019 | Waste Management and Research37 ( 9 ) , pp.906 - 913

The usage of plastics has exponentially increased in our daily lives over the past 50 years because of its durability, low costs and potential for diverse applications, such as widespread use as disposable items. In this study, first, the recycling cost of plastic wastes has been estimated by using actual data taken from a recycling centre, where plastic solid wastes were collected separately. The total amount of plastic wastes recycled at the centre was approximately 695 tonnes. The operating cost of plastics separation at the recycling centre, the transport of plastic wastes, labouring, maintenance, electricity, insurance and chem . . .ical costs were taken into consideration in the cost evaluation. Accordingly, the unit cost of recycling was calculated as US$0.40 kg-1 of plastic waste. This cost was compared with the predicted plastic recycling cost in the same region using statistical values. The predicted recycling cost was estimated based on assuming segregated collection by the municipalities of all PSW in municipal solid waste. Then the resulting unit cost of recycling was found to be US$0.25 kg-1 of plastic waste. In addition, the recycling costs were also evaluated including the revenue from the sales of recycled plastic granular. According to the evaluated total cost of plastic recycling, it can be concluded that mechanical recycling of plastics can only be an economical option if the recovery of plastics is improved. © The Author(s) 2019 Daha fazlası Daha az

Dependency of removal efficiency on electrode arrangements in the treatment of oily wastewaters by electrocoagulation

Genç, Ayten | Eryılmaz, Candan

Article | 2017 | Separation Science and Technology (Philadelphia)52 ( 9 ) , pp.1594 - 1601

Turbidity and chemical oxygen demand (COD) removal efficiencies were analyzed depending on electrode layouts by performing electrocoagulation experiments using horizontal and vertical electrochemical cells. Multiple aluminum plate electrodes were placed into different sections of the electrochemical cells. Removal efficiencies at the horizontal electrochemical cell were always higher than the one’s obtained from the vertical electrochemical cell. But the use of vertical electrochemical cell consumed less energy during the electrocoagulation tests. The highest COD removal efficiencies were 97% and 88% in the horizontal and vertical e . . .lectrochemical cells, respectively. However, the energy consumption for COD removal in the horizontal electrochemical cell was 47% higher than the energy consumed in the vertical electrochemical cell. © 2017 Taylor & Francis Daha fazlası Daha az

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