Sularda düşük derişimlerde bulunan uranyumun polimerik adsorbanla tutulmasının kinetik incelenmesi
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Date
2004
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Ankara Üniversitesi, Fen Bilimleri Enstitüsü
Abstract
Sulu ortamlardan uranyumun uzaklaştırılması amacıyla polietilen glikolün akrilonitril içindeki çözeltisinin (60)Co-γ kaynağı ile ışınlanmasından iç içe geçmiş ağ yapıları (IPN) elde edilmiştir. IPN’ler 65 (0)C de 3,5 saat amidoksimleştirildikten sonra 10(-2) M uranyum nitrat çözeltisinde 17, 25, 35 ve 45 (0)C sıcaklıklarda adsorpsiyon dengesi kurulana dek bekletilmiştir. Adsorpsiyon ölçümleri, gama spektrometresi, gravimetri ve UV spektrofotometresi ile yapılmıştır. IPN’nin amidoksimleşme öncesi, sonrası ve uranyum tutunmasından sonraki yapı analizleri FTIR spektrometresi ile yorumlanmıştır. Sıcaklık yükseldikçe, uranyumun maksimum adsorplanma miktarının arttığı belirlenmiştir. 45 (0)C sıcaklıkta IPN’nin maksimum adsorpsiyon kapasitesi 602 mg U/g dir. Ayrıca, titreşimli ortamda yapılan bir çalışmada uranyum adsorpsiyonunun biraz arttığı belirlenmiştir.
Farklı sıcaklıklardaki adsorpsiyon kapasitesinin (Q) zamanla değişimi izlenerek adsorpsiyonun 240 dakikaya kadar 0. dereceden olduğu belirlenmiştir. Sıcaklık yükseldikçe adsorpsiyon hızının arttığı gözlenmiş ve aktivasyon enerjisi 34.6 kJ/mol olarak hesaplanmıştır.
Adsorpsiyon denge sabitinin sıcaklıkla değişiminden adsorpsiyon için ΔH, ΔS ve ΔG termodinamik nicelikleri hesaplanmıştır. Adsorpsiyon olayının endotermik olduğu belirlenmiştir. Olayın difüzyon kontrollü yani fiziksel adsorpsiyon olduğu kanısına varılmıştır.
Çözeltinin derişimi 5x10(-4)-1x10(-2) M arasında değiştirilerek 20, 25, 35 ve 45 (0)C sıcaklıklarda adsorpsiyon izotermleri bulunmuştur. İzotermlerin düşük sıcaklıkta Giles C tipi iken yükselen sıcaklıkla Freundlich tipine benzediği belirlenmiştir.
In order to remove the uranium from aqueous media, the solution of polyethylene glycol in acrylonitrile was irradiated using (60)Co γ-ray source and Interpenetrating Polymer Networks (IPNs) was formed. After IPNs were amidoximated at 65 (0)C for 3.5 hours, they were kept in 10(-2) M of uranil nitrat solution at 17, 25, 35, 45 (0)C temperatures until to establish the adsorption equilibrium. Adsorption analyses were measured by gamma spectrometer, gravimetry and UV spectrofotometer. Structure analysis of IPN, before and after amidoximation and after the adsorption of uranium, was interpreted by FTIR spectrometer. It was found that as the temperature increased the amount of max adsorption also increased. The amount of max adsorption capacity at 45 (0)C was 602 mg U/g IPN. In addition to, it was determined that the uranium adsorption increased a little in shaking media. The reaction was determined as ‘zeroth degree’ until 240 minutes due to the changing of adsorption capacity by the time at different temperatures. It was observed that as the temperature increased, the adsorption rate also increased and the activation energy was calculated as 34.6 kJ/mol. By using the changing of adsorption equilibrium coefficient by the temperature, thermodynamic quantities of ΔH, ΔS and ΔG were calculated consecutively. Adsorption reaction was determined as endothermic and it was interpreted that the adsorption was controlled by particule diffusion, namely it was a physical adsorption. Adsorption isotherms were found by changing the solution concentrations from 5x10(-4) to 1x10(-2) M at 20, 25, 35, 45 (0)C temperatures. The obtained data from this study was applied to different adsorption isotherms. It was observed that at lower temperatures, the adsorption isotherms were fitted to Giles C type, at higher temperatures, they were fitted to Freundlich type.
In order to remove the uranium from aqueous media, the solution of polyethylene glycol in acrylonitrile was irradiated using (60)Co γ-ray source and Interpenetrating Polymer Networks (IPNs) was formed. After IPNs were amidoximated at 65 (0)C for 3.5 hours, they were kept in 10(-2) M of uranil nitrat solution at 17, 25, 35, 45 (0)C temperatures until to establish the adsorption equilibrium. Adsorption analyses were measured by gamma spectrometer, gravimetry and UV spectrofotometer. Structure analysis of IPN, before and after amidoximation and after the adsorption of uranium, was interpreted by FTIR spectrometer. It was found that as the temperature increased the amount of max adsorption also increased. The amount of max adsorption capacity at 45 (0)C was 602 mg U/g IPN. In addition to, it was determined that the uranium adsorption increased a little in shaking media. The reaction was determined as ‘zeroth degree’ until 240 minutes due to the changing of adsorption capacity by the time at different temperatures. It was observed that as the temperature increased, the adsorption rate also increased and the activation energy was calculated as 34.6 kJ/mol. By using the changing of adsorption equilibrium coefficient by the temperature, thermodynamic quantities of ΔH, ΔS and ΔG were calculated consecutively. Adsorption reaction was determined as endothermic and it was interpreted that the adsorption was controlled by particule diffusion, namely it was a physical adsorption. Adsorption isotherms were found by changing the solution concentrations from 5x10(-4) to 1x10(-2) M at 20, 25, 35, 45 (0)C temperatures. The obtained data from this study was applied to different adsorption isotherms. It was observed that at lower temperatures, the adsorption isotherms were fitted to Giles C type, at higher temperatures, they were fitted to Freundlich type.
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Keywords
Water -- Analysis, Su -- Analiz, Water pollution, Su kirliliği, Uranyum adsorpsiyonu, Adsorpsiyon kinetiği, IPN, Adsorpsiyon izotermleri, Adsorpsiyon termodinamiği, Çözeltiden adsorpsiyon, Uranium adsorption, Adsorption kinetics, Adsorption isotherms, Adsorption termodinamics, Adsorption from solution
Citation
Gürellier, R. (2004) Sularda düşük derişimlerde bulunan uranyumun polimerik adsorbanla tutulmasının kinetik incelenmesi. (Yayımlanmamış yüksek lisans tezi). Ankara : Ankara Üniversitesi, Fen Bilimleri Enstitüsü.