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    Mesoporous silica aerogels for sunflower oil refining and investigation of their adsorption performance
    (Springer, 2025) Soylu, Tulay Merve; Ozel, Cem; Ikizler, Burcu Karakuzu; Ozarslan, Ali Can; Terzioglu, Pinar; Elalmis, Yeliz Basaran; Yucel, Sevil
    Involving a succession of oil refining stages for edible oil production, a notable constraint lies in the necessity to employ diverse adsorbents at various steps within these processes. This study investigates the synthesis of mesoporous silica aerogels from rice husk ash, comparing their efficacy in physical sunflower oil refining with earth clay (Bentonite) and commercial silica (Trisyl). Tetraethyl orthosilicate (TEOS) impact during aging was analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and N2 adsorption-desorption analyzer to examine alterations in the structure of silica aerogels. The surface areas of TEOS-doped silica aerogel (TSA) and non-TEOS-doped silica aerogel (NTSA) were 296.18 and 267.06 m(2)/g. Mesoporous silica aerogels were evaluated for their ability to reduce free fatty acids (FFA), peroxide value (PV), phosphorus, and color pigments in sunflower oil. TSA and NTSA demonstrated significant FFA removal, with TSA at 3 wt.% achieving the highest performance of 32.2%. TSA also effectively reduced PV and phosphorus compared to NTSA, Bentonite and Trisyl, exhibiting performance similar to Bentonite in the bleaching process. TEOS-doped silica aerogels have shown promise as adsorbents for impurity removal in sunflower oil and has emerged as the potential adsorbent that can comprehensively and effectively meet the requirements of many edible oil physical refining applications in a singular step. Mesoporous silica aerogel synthesis from rice husk ash with/without TEOS-doping. Mesoporous silica aerogels were compared to commercial adsorbents. For the first time mesoporous silica aerogels were used for oil adsorption with promising results. TEOS-doped silica aerogel was used to remove acids and peroxide in oil purification effectively. TEOS-doped silica aerogel performed effective color and phosphorus removal in oil purification.
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    The effect of process variables on the properties of nanoporous silica aerogels: an approach to prepare silica aerogels from biosilica
    (Springer, 2017) Temel, Tulay Merve; Ikizler, Burcu Karakuzu; Terzioğlu, Pınar; Yucel, Sevil; Elalmis, Yeliz Basaran
    Silica aerogel, a nanoporous material, was produced by using rice husk ash via sol-gel method. The aim of the study is to examine effects of the acid type (acetic, hydrochloric, nitric, oxalic and sulfuric acid), dryer type (air, freeze, oven and vacuum) and the addition of tetraethyl orthosilicate on the structural and physical properties of aerogels produced from rice husk ash. In addition, this is the first study investigating the effect of vacuum oven drying on the structure of rice husk based silica aerogel. Specific surface area and pore size of obtained silica aerogels have been analyzed by the N-2 adsorption and desorption measurements at 77 K via Brunauer-Emmett-Teller (BET) and Barrett-Joiner-Halenda (BJH) methods, respectively. Surface functional groups were determined with fourier transform infrared spectroscopy (FTIR). Surface morphology was examined with scanning electron microscopy (SEM). Moreover, density was calculated by tapping method. The results showed that all of the variables had remarkable effects on the final properties of the silica aerogel. The BET specific surface area of the silica aerogels increased with the addition of tetraethyl orthosilicate, while the tapping density decreased. The BET specific surface area and pore size of silica aerogels varied between 140.7-322.5 m(2) g(-1), and 5.38-12.05 nm, respectively. Silica aerogel which was obtained by using oxalic acid, tetraethyl orthosilicate addition and air dryer had the highest BET specific surface area (322.5 m(2) g(-1)).