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Öğe Acute Toxicity of Organophosphorus Pesticides and Their Degradation By-products to Daphnia magna, Lepidium sativum and Vibrio fischeri(INTECH EUROPE, 2011) Aydin, Mehmet Emin; Ozcan, Senar; Beduk, Fatma[Abstract not Available]Öğe CHEMICAL OXIDATION OF DIAZINON IN AQUEOUS SOLUTION BY OZONATION(PARLAR SCIENTIFIC PUBLICATIONS (P S P), 2011) Beduk, Fatma; Aydin, Mehmet Emin; Ozcan, SenarIn the present study, the decomposition of diazinon by O-3, O-3/UV, and O-3/UV/H2O2 processes was studied. Diazinon and its oxidation by-product, diazoxon, were identified using gas chromatography/mass spectrometry (GC-MS). Chemical oxidation of diazinon in aqueous solution by ozonation was studied under various solution pH values and 03 concentrations. Acidic and alkaline solutions accelerated diazinon degradation, and complete mineralization of diazinon was achieved in 30 min at pH 9.0. Diazinon removal increased with ozone dosage, however, 2.0 mg L-1 of ozone with 30 min oxidation time was more economical and efficient. O-3/UV/H2O2 combination enhanced decomposition of both diazinon and diazoxon due to the reaction between analytes and hydroxyl radicals. Toxicity measurements of the treated solutions were carried out in order to evaluate the efficiency of the treatment methods. The present study validated that O-3/UV/H2O2 combination is a feasible process for the removal of the tested pesticide from aqueous solutions.Öğe Degradation of Malathion and Parathion by Ozonation, Photolytic Ozonation, and Heterogeneous Catalytic Ozonation Processes(WILEY-BLACKWELL, 2012) Beduk, Fatma; Aydin, Mehmet Emin; Ozcan, SenarThe oxidation of organophosphorus pesticides (OPPs), such as malathion and parathion, in aqueous solution was studied using conventional ozonation (O3), photolytic ozonation (O3/UV, O3/UV/H2O2), and heterogeneous catalytic ozonation (O3/TiO2/UV) processes. Experiments were performed in batch mode at laboratory scale and processes were compared in terms of disappearance kinetics. The best results of pesticide mineralization were obtained when TiO2 particles in combination with ozone (O3) and UV photolysis (??=?254?nm) were applied. Decomposition of 99% of parent compounds were achieved in 10?min and oxon derivatives were completely removed in 30?min. The initial reaction rate increases linearly with increasing catalyst amount. Toxicity measurements of the treated solutions were carried out in order to evaluate the efficiency of the treatment methods. No detoxification was achieved for O3 and O3/UV applications. Heterogeneous photocatalytic ozonation was shown to be feasible for achieving complete decomposition of OPPs and their oxon intermediates.Öğe THE EVALUATION OF GLOBAL WARMING'S EFFECTS ON SOIL TEMPERATURE OF TURKEY BY 3.5D GEOGRAPHICAL INFORMATION SYSTEM MODELS(INT SCIENTIFIC CONFERENCE SGEM, 2010) Corumluoglu, Ozsen; Aydin, Mehmet Emin; Asri, Ibrahim; Ozcan, Senar; Beduk, FatmaIn this study, global warming's effects on soil temperature of Turkey was evaluated by analysis of the spatial and temporal variations of the soil temperature data with the help of 3.5D Geographical Information System (GIS) Models. Soil temperature data in 5 cm, 10 cm, 20 cm, 50 cm and 100 cm depths in 74 city centers since 1975 were used. These data were compared with 34 years mean temperature of each city and deviations were shown by using GIS on the map. It is determined that soil temperature values in Turkey have risen about +4 degrees C in all months since 1998 except November, December and January. In deeper soil parts, temperature changes are not evident in the models. Data of 5 cm depth soil temperature in the periods of February and November 1977, April 1989, March 2001, January, March, April, July and August 2008 show an upward trend up to 5 degrees C in whole country. Semi-arid lands of Turkey are quite susceptible to temperature increases. As a result of global warming, higher temperature and lower precipitation cause higher soil temperatures in the region and this trouble results with reduction in crop quantity and quality.Öğe REMOVAL OF LINDANE AND DIELDRIN FROM AQUEOUS SOLUTIONS BY MONTMORILLONITE AND BENTONITE AND OPTIMIZATION OF PARAMETERS(PARLAR SCIENTIFIC PUBLICATIONS (P S P), 2009) Aydin, Mehmet E.; Ozcan, Senar; Beduk, FatmaDifferent pesticides are widely applied in agricultural activities. To remove these toxic compounds from the aquatic environment and to reduce the dispersion of pollutants, different clays can effectively be used as alternative adsorbents to commonly used activated carbon. In this study montmorillonite and bentonite clays were used to adsorb lindane (gamma-HCH) and dieldrin, by a batch equilibration technique. The study was carried out as functions of contact time, pH, initial lindane and dieldrin concentrations, amount of montmorillonite and bentonite and adsorption isotherms were obtained as Freundlich Isotherm. Clays were activated by calcination and acid treatment. Adsorption was improved after acid treatment of used clays, however calcinations of the clays up to 500 degrees C did not reveal any discernible effect on the adsorption.Öğe Removal of lindane from an aqueous solution by using aminopropyl silica gel-immobilized calix[6]arene(ELSEVIER SCIENCE BV, 2013) Tor, Ali; Aydin, Mehmet Emin; Aydin, Senar; Tabakci, Mustafa; Beduk, FatmaAn aminopropyl silica gel-immobilized calix[6]arene (C[6]APS) has been used for the removal of lindane from an aqueous solution in batch sorption technique. The C[6]APS was synthesized with p-tert-butylcalix[6]arene hexacarboxylate derivative and aminopropyl silica gel in the presence of N,N'-diisopropyl carbodiimide coupling reagent. The sorption study was carried out as functions of solution pH, contact time, initial lindane concentration, C[6]APS dosage and ionic strength of solution. The matrix effect of natural water samples on the sorption efficiency of C[6]APS was also investigated. Maximum lindane removal was obtained at a wide pH range of 2-8 and sorption equilibrium was achieved in 2 h. The isotherm analysis indicated that the sorption data can be represented by both Langmuir and Freundlich isotherm models. Increasing ionic strength of the solutions increased the sorption efficiency and matrix of natural water samples had no effect on the sorption of lindane. By using multilinear regression model, regression equation was also developed to explain the effects of the experimental variables. (C) 2013 Elsevier B.V. All rights reserved.
