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Öğe Adsorptive separation of adipic acid from aqueous solutions by perlite or its composites by manganese or copper(Techno-Press, 2014) Uslu, Hasan; Demir, Goksel; Bayat, Cuma; Wasewar, Kailas L.; Bamufleh, Hisham S.Adipic acid (hexane-1,6-dioic acid) is one of the most used chemical in industrial applications. This must be separated from any environmental contaminant. In this study, adipic acid separation from wastewater by adsorption method onto Perlite or Perlite + Mn or Perlite + Cu composites was investigated. Adsorption of Adipic acid was investigated in terms of equilibrium, and thermodynamic conditions. For thermodynamic investigations the experiments carried out at three different temperatures (298 K, 318 K, 328 K). In the equilibrium studies, 2 g of perlite and its composites were determined as the optimal adsorbent amount. Freundlich and Langmuir isotherms were applied to the experimental data. Freundlich isotherms for all temperatures used in this work gave some deviations with R square values under 0.98 where as Langmuir isotherm gave good results with R square values upper 0.99 at different temperatures. As a result of thermodynamic studies, adsorption enthalpy (Delta H), adsorption entropy (Delta S), and adsorption free energy (Delta G) have been calculated for each adsorbents.Öğe Comparative Evaluation of Various Advanced Oxidation Processes for the Treatment of Textile Industry Effluents(Beykent Üniversitesi, 2009) Yigit, Selda; Coban, Aslı; Demir, GokselTreatment of textile industry effluents is extremely difficult due to their high content of color and recalcitrant organic compounds. However, advanced oxidation is a reasonable treatment alternative for this type of wastewater. In this paper, applicability of advanced oxidation processes on textile industry effluents was discussed and it is based on five major types of advanced oxidation. These processes are Fenton-Photo Fenton, O3/H2O2, O3/UV, H2O2/UV and TiO2 photocatalysis (TiO2/UV). As a result of this literature review, Fenton - Photo Fenton process is concluded to be favorable than other advanced oxidation processes because of its efficiency and operation simplicity. Nonetheless, all of these processes are suitable for textile wastewater treatment with various advantages and disadvantages on the treatment.Öğe Extractive Separation of Pentanedioic Acid by Amberlite LA-2 in Various Solvents(Amer Chemical Soc, 2016) Uslu, Hasan; Bamufleh, Hisham S.; Keshav, Amit; Pal, Dharm; Demir, GokselReactive extraction of pentanedioic acid using Amberlite LA-2 in different diluents, such as hexane, methylbenzene, kerosene, 4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone, n-hexanone, 3-methyl-1-butanol, n-octanol, nnonanol, and n-decanol, respectively, was studied. At lower amine concentrations, K-D values of less than 1 were obtained but it improves as amine concentration was raised. Increase in amine concentration was found to increase the KD by 80-85% in inert diluents (hexane, methylbenzene and kerosene). In the chosen ketones, the extraction percentage follows the following trend 4-methyl-2-pentanone > DIBK > n-hexanone. Among the various diluents used, higher KD was obtained when alcohols were used as diluents. Mass action equilibria, linear solvation energy relationship modeling, and differential evolution (DE) was applied for estimating the model parameter and compare the model values with the experimental results of extraction equilibria.Öğe Heavy metal amounts in soil and sediments of surface water sources in the industrial regions of Istanbul(Destech Publications, Inc, 2007) Ozbas, Emine Elmaslar; Ozcan, H. Kurtulus; Balkaya, Nilgun; Demir, Goksel; Bayat, CumaToday, heavy metal-oriented soil pollution composes a substantial problem, especially in regions with dense industrial activities. Industrial wastes may also be introduced to superficial waters either directly or indirectly, forming a dense accumulation of heavy metal in aquatic sediments. Istanbul exhibits a high density of industrial activities. In this study, soil and sediment samples were taken from 4 superficial water resources in the dense industrial region that borders Istanbul. In the first section of the study, the heavy metal concentrations (Cu, Ni, Zn, Pb, Cd) in these samples were determined and compared with each other. In the second section of the study, after the comparison with similar studies in the literature, an assessment was made.Öğe Heavy metal concentrations of atmospheric ambient deposition dust in Istanbul-Bosphorus Bridge tollhouses(Destech Publications, Inc, 2007) Ozcan, H. Kurtulus; Demir, Goksel; Nemlioglu, Semih; Sezgin, Naim; Bayat, CumaAir Pollution emissions due to motor vehicle-related traffic on motorways are sent into the atmosphere. Along with many pollutants from motor vehicles because of fossile fuel usage, heavy metals are also emitted as particles with exhausted gas. Heavy metals are one of the important parameters among environmental pollution sources. Heavy metals from motor vehicles may be found as PM in motorway atmosphere and be involved in street dust by depositing on roads as atmospheric precipitates. Bridge tollhouses are one of the most closely encountered environments of human beings with this kind of dust. In this study, time-related changes of atmospheric precipitate depositing per unit area were determined on breathing height of tollhouse workers, as well as concentrations of lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), and nickel (Ni) were measured. The study area was Istanbul Bosphorus Bridge, which is one of the busiest points of the world (referred to as the junction point of Asia and Europe) after it was merged to international D-100 motorway. According to the results obtained from the samples collected in ten different times during thirteen months, average lead concentration was found to be 1454.65 mg/kg dry soil, where the concentrations of copper, zinc, cadmium, and nickel were 399.12, 2034.78, 24.37, and 140.92 mg/kg dry soil, respectively.Öğe Investigation of efficiency of amberlite XAD-16 on adsorption of 2,4,6-trinitrophenol (TNP)(Desalination Publ, 2012) Uslu, Hasan; Demir, Goksel2,4,6-trinitrophenol (picric acid or TNP) is toxic and hazardous material for the environment. It must be treated from any environmental contaminant. In this study, separation of TNP was aimed from aqueous solutions by Amberlite XAD-16 polymeric resin with adsorbtion method. Adsorption of TNP was investigated in terms of equilibrium, kinetics and thermodynamic conditions. For thermodynamic investigations the experiments carried out at three different temperatures (298 K, 308 K, 318 K). In the equilibrium studies, 1.5 g of Amberlite XAD-16 was determined as the optimal amount. The most used isotherms, Freundlich and Langmuir, were applied to the experimental data. The Langmuir isotherm gave good results with R square values about 0.99 at different temperatures. In the kinetic studies, pseudo-first, and pseudo-second order models were applied to the kinetic experiments. The pseudo second order was fitted to this adsorption system with an R square value of 0.987. In the thermodynamic studies, Delta H-ads(0) = -24.6 kJ/mol . Delta S-ads(0) = -209 J/molK and Delta G(ads)(0) for different temperatures were calculated.Öğe Modeling of Methane Distribution in a Landfill Using Genetic Algorithms(Mary Ann Liebert, Inc, 2009) Ozcan, H. Kurtulus; Balkaya, Nilgun; Bilgili, Erdem; Demir, Goksel; Ucan, O. Nuri; Bayat, CumaLandfill gas (LFG) results from the biologic decomposition of municipal waste and consists of mostly methane (CH4) and carbon dioxide (CO2), as well as trace amounts of a variety of other compounds. In this study, the major landfill gas emissions produced in Istanbul Hasdal landfill were investigated and modeled. In the investigated area, CH4, CO2, and O-2 measurements were made for 3.5 years in order to monitor long-term variations. In addition, a supervised algorithm for the evaluation of CH4 concentration using a genetic algorithm (GA) was developed and applied to real data. The model and the actual measurement results were compared and statistically evaluated. It was observed that the long term changes of the CH4 concentrations can be estimated effectively by the GA model structure. A correlation with 0.86 value was ascertained between the actual values and model results. The results of the study indicated that the GA can be used in modeling landfill gases generated in solid waste deposition areas.Öğe Prediction of Tropospheric Ozone Concentration by Employing Artificial Neural Networks(Mary Ann Liebert, Inc, 2008) Ozdemir, Huseyin; Demir, Goksel; Altay, Gokmen; Albayrak, Sefika; Bayat, CumaAir pollution modeling and prediction have great importance in preventing the occurrence of air pollution episodes and provide sufficient time to take the necessary precautions. Recently various algorithms such as artificial neural networks (ANNs) is applied to air quality modeling. The present work aims to predict tropospheric ozone concentration by the ANN with three pollutant parameters and eight meteorological factors in selected areas. We have preferred three-layer perceptron type of ANNs, which consists of input, hidden, and output layers, respectively. To evaluate the performance of the ANN model, selected statistical performance parameters are used. The overall system finds correlation parameter, r between 0.8 and 0.9 for the test data sets. Therefore, results show the successful follow of estimated ozone concentrations by the model with the observed values. Finally, it was seen that the ANN is one of the compromising methods in estimation of environmental complex air pollution problems.Öğe Removal of Ferrous Iron and Manganese From Water Using Oxidation and Filtration Technique(Beykent Üniversitesi, 2009) Tufekci, Nese; Balcioglu, Esra Billur; Demir, Goksel; Borat, MehmetIn oxygen-free aquatic environments, such as groundwaters and hypolimnetic waters of eutrophic lakes, iron and manganese exist predominantly in the ferrous state Fe(II) ions and manganese state Mn(II) ions. Even though iron and manganese removal processes used commonly nowadays were invented in the 19th century, there are still significant gaps in our knowledge. The basic process used for iron and manganese removal is to oxide soluble iron and manganese compounds so that they are converted to insoluble iron and manganese compounds, and these oxidation products are removed by either precipitation and/or filtering. For this reason, in this study the oxidation with air process and slow sand filters were used in decreasing iron and manganese concentrations increasing especially during summer to desired limits. Furthermore both of the processes were compared. The oxidation of Fe(II) ions or Mn(II) ions by aeration is analyzed in a reaction tank which consists of 2 L flask where pH and temperature is kept constant. The temperature of the reaction solution and the partial pressure of the oxygen are kept at 25°C and 0.25 atm, respectively. Model filter is made of 10 cm internal diameter and 50 cm height plexiglas material. Two reactors with a volume of 4 L are used. The feeding flow of the reactor is 50 ml/min. The aim of this study was to investigate the mechanisms of Mn(II) ions and Fe(II) ions removals in oxide-coated filters and the oxidation of Mn(II) ions and Fe(II) ions with atmospheric oxygen. In literature, even though it is stated that autocatalytic effects are highly clear when the initial concentration of Fe(II) ions and Mn(II) ions are over 5mg/L, the same effect has also been observed in low concentration values by this experiment. Generally the efficiency of Fe (II) ions removal rate with uncoated sand filter is about 85 %, with Fe-Mn coated sand filter it is about 99 %. The removal efficiency rates of Mn(II) ions are approximately 80% and 99% for uncoated filter and Fe-Mn coated sand filter, respectively. As a result, the oxidation rate in the filter is higher than that of in the aeration pool.
