Silika aerojel sentezinde farklı katalizör kullanımının etkisi ve adsorbsiyon kapasitesinin belirlenmesi

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Thesis Type: Postgraduate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, -, Turkey

Approval Date: 2019

Thesis Language: Turkish

Student: AYŞE ENES

Supervisor: HABİBE CANAN CABBAR

Open Archive Collection: AVESIS Open Access Collection

Abstract:

Porous materials are used in many fields today. Aerogels, a type of porous material, are generally transparent solids in which the liquid in the pores is replaced with air. Aerogels, although there are species such as organic aerogel and inorganic aerogel, silica aerogel, which is included in the inorganic group, is the most widely used aerogel type due to its many qualified properties. In this study, the effect of different catalyst usage on hydrophobic silica airgel synthesis was investigated. In the experimental study, in the first stage of hydrophobic silica aerogel synthesis by sol-gel method, tetraethylorthosilicate (TEOS) was used as the precursor of silica source. NH4OH, KOH, NaOH were used. In this part of the experimental step, the highest surface area was obtained as HCl-KOH acid base pair. In the other study, composite silica aerogel was obtained by adding expanded graphite in different ratios to the synthesized hydrophobic silica aerogels. The obtained silica was adsorbed to aerogels in methylene blue; pH, initial methylene blue concentration, temperature effects were investigated. Experimental results; Langmuir, Freundlich and Temkin adsorption isotherms. The isotherms were found to confirm to Langmuire. Isotherm data obtained at different temperatures were applied to thermodynamic equations and thermodynamic parameters such as (ΔH, ΔS and ΔG); 25.4 kj / mol, 78.3 j / mol N, -1.89, -0.37 and -0.36 kj / mol for ΔG (30,40,50 0C) respectively.