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Öğe Comparison performances of hybrid sonocatalysis and sonophotocatalysis on the elimination of 2,4-dichlorophenoxyacetic acid in water: Mineralization and economic analysis(Hard, 2022) Dikmen, Emre; Doğdu, Gamze; Yalçuk, ArdaThis study compares the removal performances of sonocatalysis (SC) coupled with commercially available titanium dioxide ( TiO2, P25) and combined sonophotocatalysis (SPC) with H2O2 of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in aqueous media in batch experiments. A SC process (US/TiO2) with 75 mg/L 2,4-D obtained 65.58 +/- 0.42% degradation, 7.84 +/- 1.3% mineralization, and 15.86 +/- 0.39% oxidation at a pH of 2, and a temperature of 35 +/- 1 degrees C under optimum conditions after 360 minutes, whereas 82.24 +/- 2.91% degradation, 44.50 +/- 0.11% mineralization, and 55.11 +/- 0.35% oxidation were obtained after 360 minutes with SPC (US/ UVA/TiO2-H2O2), with the addition of an optimum 250 mg/ L of H2O2. The synergistic index was calculated as 1.77 that indicated the positive effect of the combined system on degradation efficiency when compared with the individual processes. Total costs were obtained as 5072 USD/ kg for SC and 4135 USD/kg for SPC, showing the cost efficiency of the hybrid SPC process in comparison to the SC process. The obtained results confirmed that the hybrid SPC process was more effective than the SC process in degrading and mineralizing 2,4-D for removal. Operation time was shorter, energy consumption was lower, and operation cost was lower when compared to the SC process.Öğe Links between airborne microbiome, meteorology, and chemical composition in northwestern Turkey(Elsevier, 2020) Lang-Yona, Naama; Öztürk, Fatma; Gat, Daniella; Aktürk, Merve; Dikmen, Emre; Zarmpas, Pavlos; Tsagkaraki, MariaThe composition of atmospheric aerosols is dynamic and influenced by their emission sources, organic and inorganic composition, transport pathways, chemical and physical processes, microorganisms' content and more. Characterization of such factors can improve the ability to evaluate air quality and health risks under different atmospheric scenarios. Here we investigate the microbial composition of the atmospheric particulate matter (<10 mu m; PM10), sampled in Bolu, Turkey, and the linkage to the chemical composition changes, and different environmental factors. We showdistinct differences between aerosol composition of different sources and air-mass transport patterns, sampled in July-August 2017 and in February 2018. The summer samples had a typical northern component air mass trajectories and higher local wind speed. They were characterized by high PM10 levels, marine and mineral dust tracers and high relative abundance of Ascomycota, suggesting long-range transport of the particles from remote sources. In contrast, samples collected in February were characterized by a dominant contribution of southern air masses, and low wind speed. They had low PM10 values, higher relative abundance of antibiotic resistance genes and anthropogenic ions related to local industries and farming, suggesting a dominance of local sources. With the microbiome analyses reported here for the first time for this region, we show good agreement between airborne microbial composition, aerosol mass load, chemistry, and meteorology. These results allow better air quality evaluation and prediction capabilities. (C) 2020 Elsevier B.V. All rights reserved.Öğe Photocatalytic degradation of yellow 2G dye using titanium dioxide/ultraviolet A light through a Box-Behnken experimental design: Optimization and kinetic study(Taylor & Francis Inc, 2019) Okçu, Gamze Doğdu; Tunacan, Tuğba; Dikmen, EmreYellow 2G (Y2G), a type of anionic, synthetic monoazo dye that is widely used in household applications, textiles, and food industries, has been found to have cardiovascular and neurological effects on all living beings. In the present study, heterogeneous photocatalytic degradation of commercial Y2G was conducted using pure titanium dioxide (TiO2) in a batch reactor system under ultraviolet A (UVA) light for 180 min. TiO2 dosage, pH, and initial Y2G concentration were the three experimental parameters selected and studied to obtain preliminary information about the photocatalytic activities within a specified range. The Box-Behnken design method (BBD) was used to determine optimal values of the results using the above parameters of Y2G photocatalysis under response surface methodology (RSM). The optimum conditions were 0.914 g L-1 TiO2, pH 3.45, and an initial Y2G concentration of 20 mg L-1. The Y2G degradation efficiency was 96.19% using a second-order polynomial equation with R-2 approximate to 0.999. The experimental results also showed that the photocatalytic process could be successfully explained using the modified Langmuir-Hinshelwood model, where k(c) and K-LH were 0.787 mg L-1 min and 0.010 L mg(-1), respectively.Öğe Removal of indigo dye by photocatalysis process using Taguchi experimental design(2019) Okçu, Gamze Doğdu; Tunacan, Tuğba; Dikmen, EmreThe major concern of the present research is degradation of hazardous and stable Indigo dye used in industrial denim dying process. For this purpose, a heterogeneous photocatalysis process was carried out to treat aqueous solution of Indigo dye using pure titanium dioxide ($TiO_2$) in a batch reactor system under ultraviolet A (UVA) light for 210 min. In the study, individual and synergistic effects of factors such as $TiO_2$ dosage, pH, and initial dye concentration were scrutinized. Moreover, Taguchi statistical method was performed to optimize influential parameters. The results obtained from the study that $TiO_2$ concentration had the most effective factor on the Indigo dye degradation. The optimal conditions for dye removal were A (pH) at level 2 (4), B (initial dye concentration) at level 1 (10 mg $L^{-1}$) and C ($TiO_2$ concentration) at level 4 (1.5 g $L^{-1}$). The results presented that the theoretically predicted value for degradation efficiency (100%) was confirmed by the experimental value (100%).Öğe Sulardan 2,4-Diklorofenoksi asetik asit (2,4-D) herbisitinin sonokataliz ve sonofotokataliz yöntemleriyle arıtılması(Bolu Abant İzzet Baysal Üniversitesi, 2020) Dikmen, Emre; Yalçuk, Arda; Okçu, Gamze DoğduYapılan bu çalışmada, 2,4-Diklorofenoksi asetik asit (2,4-D) herbisitinin hibrid sonokataliz ve sonofotokataliz arıtma sistemleri kullanılarak sulu çözeltiden giderilmesi çalışılmıştır. Proseslerde ticari formdaki Amin EXT 500 SL® 2,4-D amin tuzu herbisitinin laboratuvar koşullarında kesikli parçalanma ve mineralizasyon performansı incelenmiştir. Proseslerin optimizasyonu için Taguchi Deneysel Dizaynı kullanılmıştır. Sonokataliz prosesi için optimum olarak pH 2, TiO2 konsantrasyonu 0.5 g/L, başlangıç 2,4-D konsantasyonu 75 mg/L ve 60 dakika proses süresi elde edilirken, sonofotokataliz prosesi için ise pH 3, başlangıç 2,4-D konsantasyonu 50 mg/L, TiO2 konsantrasyonu 1 g/L, H2O2 konsantrasyonu 250 mg/L ve 60 dakika proses süresi elde edilmiştir. Deneyler UV-A ışıması altında (365 nm/36 Wm-2) ve 35±1°C sıcaklıkta gerçekleştirilmiştir. Optimum koşullar elde edildikten sonra yapılan 6 saatlik mineralizasyon deneyi sonucunda sonokataliz için %65,58?±?0.42 parçalanma, %7,84?±?1.3 mineralizasyon, %15,86?±?0.39 oksidasyon ve %57,05 AOX giderim verimi elde edilirken, sonofotokataliz için ise %82,25±?2.91 parçalanma, %44,50?±?0.11 mineralizasyon, %55,13?±?0.35 oksidasyon ve %72,03 AOX giderim verimi elde edilmiştir. Bu çalışmayla sulardan birleşik sonokataliz ve sonofotokataliz prosesleri kullanılarak 2,4-D herbisitinin parçalanması ve mineralizasyonu başarıyla gerçekleştirilmiştir.
