Benzen Uçucu Organik Bileşiğinin Badem Kabuğundan Üretilen Char Üzerine Gaz Fazı Adsorpsiyonu: Kinetik, Denge ve Termodinamik

Abstract

Uçucu Organik Bileşikler (UOB), soluduğumuz açık ve kapalı ortam hava kirleticilerinin yaygın bileşenleridir. Bu çalışmanın temel amacı, en önemli UOB’ler biri olan benzenin badem kabuklarından üretilen char adsorbenti üzerine gaz fazı adsorpsiyon prosesini incelemektir. Bu bağlamda, gaz-fazı benzen taşıyıcı olarak azot akış hızı (60-150 mL/min), adsorpsiyon sıcaklığı (20-40℃), adsorbent miktarı (40-120 mg) ve giriş akımındaki gaz-fazı benzen konsantrasyonu (9-18 ppm) gibi adsorpsiyon koşullarının hem adsorpsiyon kapasitesi hem de adsorpsiyon verimi üzerindeki etkileri gaz kromatografi yöntemi kullanılarak incelenmiştir. Bunun yanı sıra, farklı sıcaklıklarda, adsorpsiyon prosesinin kinetiği, izotermi ve termodinamiği araştırılmıştır. Char adsorbentinin karakterizasyonu BET yüzey alanı ve FTIR ölçümleri ile gerçekleştirilmiştir. Sonuçlar, Langmuir izotermi ve sözde-ikinci dereceden modellerin diğer modeller ile kıyaslandığında deneysel verileri daha iyi tanımladığını göstermiştir. Char adsorbentinin maksimum tek katmanlı adsorpsiyon kapasitesi (q_max) 25℃ için 10.56 mg g^-1 olarak bulunmuştur. Termodinamik analizler (ΔG° = -19.460 kJ mol^-1, ΔH° = -26.65 kJ mol^-1, ΔS° = -0.024 kJ mol^-1 K^-1) adsorpsiyon prosesinin kendiliğinden, ekzotermik ve fiziksel olduğunu göstermiştir. Elde edilen sonuçlar ışığında, badem kabuğundan üretilen char adsorbentinin, çevre ve insan sağlığına ilişkin riskleri nedeniyle gaz-fazı benzenin adsorpsiyon yöntemiyle çevresel kontrolünü sağlamak için önemli bir potansiyele sahip olduğu söylenebilir. 

Keywords

• Badem kabukları,Benzen,Gaz fazı adsorpsiyon,Kinetik,İzoterm,Termodinamik

Gas Phase Adsorption of Benzene Volatile Organic Compound onto Char Produced from Almond Shells: Kinetics, Equilibrium and Thermodynamics

Abstract

Volatile Organic Compounds (VOCs) are prevalent components of indoor and outdoor air pollutants that we breathe. The main purpose of this study is to investigate gas phase adsorption process of benzene, which is one of the most important VOCs, onto char adsorbent produced from almond shells. In this context, the effects of the adsorption conditions such as nitrogen (N₂) gas flow rate (60-150 mL min^-1) as the gas phase benzene carrier, adsorbent amount (40-120 mg), concentration of gas phase benzene at the inlet (9-18 ppm) and the adsorption temperature (20-40℃) on both the adsorption capacity and the adsorption efficiency were investigated using gas chromatography method. In addition, the kinetics, isotherms and thermodynamics of the adsorption process were investigated at different temperatures. The characterization of the char adsorbent was performed by BET surface area and FTIR measurements. The results showed that the Langmuir isotherm and pseudo-second-order models described the experimental data better when compared to the other models. The maximum monolayer adsorption capacity (q_max) of char adsorbent was found to be 10.56 mg g^-1 for 25℃. Thermodynamic analysis (ΔG° = -19.460 kJ mol^-1, ΔH° = -26.65 kJ mol^-1, ΔS° = -0.024 kJ mol^-1 K^-1) showed that the adsorption process was spontaneous, exothermic and physical. In the light of the results obtained, it can be said that char adsorbent produced from almond shell has an important potential for environmental control by the adsorption method of gas-phase benzene due to the risks related to the environment and human health. 

Keywords

• Almond shells,Benzene,Gas phase Adsorption,Kinetics; Isotherms,Thermodynamics

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