Özdemir, Kadir

Article | 2016 | Fresenius Environmental Bulletin25 ( 12 ) , pp.6202 - 6214

In recent years, carbon nanomaterials have been used widely in water treatment technology. This study investigates to the removal of THMs from chlorinated drinking water sources by combined coagulation process using single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Terkos Lake water (TLW), Buyukçekmece Lake water (BLW) and Ulutan Lake water (ULW) were used as drinking water source in this study. Conventional coagulation using aluminum sulfate (alum) and ferric chloride (FeCl3) was also conducted using TLW, BLW and ULW samples. Also, the chlorination of raw water samples within a reaction time of 168 . . . hours was conducted in accordance with Standard Methods 5710 B. The maximum removal percentages of TTHMs (92%) was observed with combined SWCNTs and FeCl3 in chlorinated TLW, followed by BLW (82%) and ULW (78%). In BLW and ULW, TTHMs removal (86% and 83%) was highest when using FeCl3 +MWCNTs. The TTHMs removal was lowest in ULW (39% for Alum and 45% for FeCl3). On the other hand, the removal of TTHMs increases in the acidic pH levels whereas decreases alkaline pH levels. In the meantime increases the ionic strength result in decreasing the TTHMs removal for chlorinated three water sources. The results reveal that combined coagulation using carbon nanomaterials is effective for the removal of THMs from various types of chlorinated water source waters. © 2016 by PSP Daha fazlası Daha az

Altın, Süreyya | Altın, Ahmet | Kahraman, Bekir Fatih | Alemdar, Sonay | Alaydın, Elif

Article | 2015 | Fresenius Environmental Bulletin24 ( 1B ) , pp.302 - 310

In this study, the utilization of dried activated sludge for removal of Cd2+ from aqueous solution in a batch system was investigated. Initial pH, biosorbent dosage, contact time, and initial metal concentration parameters were selected to determine optimal process conditions. The bi-osorption mechanism was examined by SEM, FTIR and EDX results. The optimum conditions for Cd2+ biosorption were found to be 6.0, 120 min., 1.2 g. L-1 and 80 mg. L-1, respectively for initial pH, contact time, biosorbent dosage and initial Cd2+ concentration. Langmuir and Freundlich isotherms were used to model the biosorption equilibrium data, and it wa . . .s determined that the system followed the Langmuir isotherm, and the sorption capacity of the biosorbent was found to be 15.43 mg.g-1. Biosorption followed a pseudo-second-order rate model. Two main mechanisms of Cd2+ biosorption onto the dried activated sludge were adsorption to the C-H bonds and ion exchange with Na+, K+ and Ca2+ ions Daha fazlası Daha az

Yıldırım, Yılmaz | Bayramoğlu, Mahmut | Hasıloğlu, Samet

Article | 2003 | Fresenius Environmental Bulletin12 ( 10 ) , pp.1173 - 1179

Air pollution continues to be a major problem in many countries. Mathematical models are useful in relating emissions to air quality under a variety of meteorological conditions and source emission concentrations over an urban area. Meanwhile, the forecasting capability of sophisticated models is limited to very large and complex terrains. In this study, an adaptive neuro-fuzzy logic method has been developed to estimate the impact of meteorological factors on SO2 pollution levels. The model satisfactorily forecasts the trends of SO2 concentration levels with a performance between 78-90%.

Yıldırım, Yılmaz

Article | 2010 | Fresenius Environmental Bulletin19 ( 7 ) , pp.1320 - 1327

In this study, an adaptive neuro-fuzzy logic method has been proposed to estimate roadside NO2 concentration levels. In the analysis, data from summer and winter seasons were modeled separately and five statistical measures, namely, RMSE, IA, R2, NMSE and FB, were used for modeling evaluation. The available data (N=5797) for 2003 were divided into three categories: training, testing and checking, to set up the ANFIS model. The model was trained using 4923 data with 13 input variables consisting of air quality and meteorological data. Summer season data set (between July and August, N=361) and winter season data set (between December . . . and February, N=361) have been separately used for prediction (testing) purposes. In general, RMSE (4.78 and 4.53), NMSE (0.029 and 0.026) and FB (0.03 and 0.01) values are low but IA (0.96 and 0.98) and R2 (0.92 and 0.95) are reasonably high enough to predict the observed values for winter and summer season test data, respectively. In addition, the FOEX values show that the model slightly under-predicts for all input parameters. Overall, the statistical measures confirm the adequacy of the model for predicting NO2 levels in M25 Roadside for winter and summer season test data. © by PSP Daha fazlası Daha az

Altın, Süreyya | Özgüven, Melih

Article | 2011 | Fresenius Environmental Bulletin20 ( 3 ) , pp.631 - 638

This study analyzed the zinc transport in supported liquid membrane (SLM) systems in which different anionic (Aliquat336) and cationic (D2EHPA) carriers, different solvents (kerosene and toluene) and different feed (deionized water and HCl) / stripping solutions (H3PO4, HCl and H 2SO4) were used. The results were modeled according to steady state (Fick's first law) and non-steady state kinetics approaches and the concordance of the models was discussed. It was observed from the experimental studies that 80.4% zinc transport could be achieved when deionized water was used as feed solution, kerosene/ D2EHPA (0.01 M) as membrane soluti . . .on combination and H3PO4(0.5 M) as stripping solution. Whilst the zinc transport efficiency was found to be 86.5% when HCl (1.0 M) was used as feed solution, toluene-Aliquat336 (0.02 M) as membrane solution combination and HCl (0.5 M) as stripping solution. Modeling studies established that the nonsteady state approach better represented zinc transport. It was therefore concluded that the zinc transport mechanism was affected by interface reactions rather than diffusion. © by PSP Daha fazlası Daha az

Uyar, Güray | Ören, Muhammet | Yıldırım, Yılmaz | İnce, Mahir

Article | 2007 | Fresenius Environmental Bulletin16 ( 2 ) , pp.182 - 192

This study was carried out from May 2003 to October 2004 in the vicinity of Çatalagzi coal-fired power plant (CATES) located in Zonguldak, North-West Turkey, in order to investigate atmospheric heavy metal depositions by sampling and analysing Pleurocarp mosses as biomonitoring plants. Initially, ISC-ST (Industrial Source Complex-Short Term) dispersion models were used to determine theoretically the most polluted sites of CATES. After the modelling, sampling was performed in these theoretically determined grids. Samples were analyzed using graphite-furnace atomic absorption spectrometry (AAS) after wet digestion. In the region, the . . .general order of heavy metal content in samples of mosses was determined to be as follows: Fe>Pb>Ni>Cr>Cu>Co>As. Background mean levels of the metals studied, except Cu, were determined and found to be higher than that of European background. The results are also presented in the form of thematic maps using the Geographic Information System (GIS). © by PSP 2007 Daha fazlası Daha az

Altın, Ahmet | Özölçer, İsmail Hakkı | Yıldırım, Yılmaz

Article | 2009 | Fresenius Environmental Bulletin18 ( 11:00 AM ) , pp.2170 - 2180

In this study, water pollutions of the Black Sea in the Turkish costal region, particularly in the Zonguldak region, located in the western part of Turkey (southern part of the Black Sea), were investigated. Zonguldak province is a highly populated and industrialized region with two iron and steel factories, coal mining and a coal-powered energy plant. In this study; physical, chemical and bacteriological pollution of water, wastewater and surface water were conducted. The domestic and industrial wastewater discharges into 7 important surface water streams were investigated, and the effect of these discharges onto the water quality . . .of the streams and the Black Sea were discussed. This work is the first study evaluating water quality and pollution in detail in the northwest coastal region of Turkey Daha fazlası Daha az

Yıldırım, Yılmaz | Alkan, Mehmet | Oruç, Murat

Article | 2009 | Fresenius Environmental Bulletin18 ( 11 ) , pp.2072 - 2078

Power production using fossil fuels can bring significant adverse effects on the surrounding environment. In this study, detection of industrial ash turbidity from a coal-fueled power plant in marine water and its interaction with marine environment were evaluated using 3 satellite imageries. To this aim, e-Cognition v.4.0.6 software was utilized to perform detection, classification and comparison of the polluted area in the aquatic marine environment using Landsat-5 TM satellite imageries and Landsat-7 ETM + satellite imagery. Total polluted area, obtained from Landsat satellite imageries, was classified into 3 regions: highly poll . . .uted, moderately polluted and less polluted region, and their polluted field dimensions were evaluated to be 10.19 km2and 7.50 km2 for Landsat TM imageries as well as 37.73 km2 for Landsat ETM+ imagery. Total suspended solids (TSS) levels were determined as 2380±213 mg.L-1, 361±118 mg.L-1 and 57±24 mg.L-1for the highly, moderately and less polluted regions, respectively. This study may serve as a database for future comparisons to identify the trend of improvement or deterioration of coastal environment of Zonguldak Daha fazlası Daha az