Bitkisel yağların çeşitli küller üzerinde adsorpsiyonla ağartılması
Küçük Resim Yok
Tarih
2004
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Trakya Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
II ÖZET Ham ayçiçek yağının içerisinde bulunan trigliserid olmayan bileşiklerin (safsızlıklann) uzaklaştırılması için endüstride genellikle asidle aktive edilmiş ağartma topraklan kullanılmaktadır. Bu çalışmada, ağartma toprağı yerine antep fıstığı, fındık ve pirinç kabuklarının küllerindeki karbon ve oksijenli bileşikler sayesinde uygulanabilirliğini araştırmak amacıyla kullanıldı. Bu kabukların adsorpsiyon kapasiteleri belirlenerek ham ayçiçek yağımn ağartma kinetiği ve adsorpsiyon izotermi incelendi. 200, 300, 400, 500, 600, 700, 800, 900, 1000°C sıcaklıklarda bu kabukların küllendirilmesi ile elde edilen küller, ağartma verimindeki (%AV) artışın renk verici maddelerin ve safsızlıklann uzaklaştırılması ile gerçekleştiğini gösterdi. Antep fıstığı kabuğu için 600°C küllendirme sıcaklığında, pirinç ve fındık kabuğu küllerine nazaran optimum bir absorbans değeri elde edildi. Böylece ham yağın koyu renginin absorbans değerleri azaldıkça açık renge dönüştüğü görüldü. Buradaki A r ağartma prosesinin hızı şu denkleme uymaktadır: log - = -kvt A0 Ağartma prosesine en uygun optimum değere sahip 600°C de küllendirilen antep fıstığı kabuğu ile 30, 40, 50, 60, 70, 80 ve 90°C deney sıcaklıklannda ayçiçek yağımn ağartılması için absorbans ölçümleri yapıldı. Bu proses için adsorpsiyon ısısı -4.7653 kJ mol-1 olarak bulundu, burada eksi işareti ısı açığa çıktığım gösterir ve bu değer 20 kJ mol^'den daha az olduğu için, adsorbant ve adsorbat arasındaki kuvvetlerin Van der Waals kuvvetleri olduğu anlaşıldı. Bu nedenle bu tip adsorpsiyon çeşidi fiziksel veya Van der Waals adsorpsiyonu olarak kabul edilebilir. Diğer taraftan, çeşitli küller üzerinde ayçiçek yağının ağartılması için adsorpsiyon izotermleri incelendiğinde Freundlich denkleminin Langmuir denklemine göre daha uygun olduğu anlaşıldı. Sonuç olarak antep fıstığı kabuğu külünün ağartma kapasitesi (%57.8) endüstride kullanılan Bentonit EY-09'a (%67.4) yakın olduğu için, bu külün bitkisel yağlann ağartılmasında kullanılması düşünülebilir.
ABSTRACT Bleaching earths activated with acid are usually used to be removed non- triglyceride compounds (impurities) present in crude sunflower oil in industry. In this study the ashes of the pistachio, hazelnut and rice hulls instead of bleaching earth were used for the purpose of study their applicability by means of carbon and oxygen compounds in them. Bleaching kinetics and the adsorption isotherm were studied by determining the adsorption capacities of these hulls. The ashes obtained by the carbonization of these hulls at the temperatures of 200, 300, 400, 500, 600, 700, 800, 900 and 1000°C showed that the increment of in the bleaching efficiency (BE%) was due to leaching of colorizing matters and impurities. An optimum absorbance value was obtained for pistachio hull at the carbonization temperature of 600°C rather than the ashes of rice and hazelnut hulls. Thus it was shown that the dark color of crude oil converted to light color as the absorbance values decreased. Here the rate of the bleaching process obeys to that A r equation: log- - = -kvt A0 The absorbance measurements were carried out for bleaching of sunflower oil at the experimental temperatures of 30, 40, 50, 60, 70, 80 and 90°C with pistachio ash carbonized at 600°C. The adsorption heat was found as -4.7653 kJ mol-1 where the minus sign shows that the heat evolves, and it was seen that the forces between the adsorbent and adsorbate seem to be Van der Waals forces since this vlaue was less than 20 kJ mol-1. Therefore this type of adsorption may be recognized as the physical or Van der Waals adsorption. On the other hand, it was seen that the Freundlich equation was more applicable than the Langmuir equation to when the adsorption isotherms for the bleaching of sunflower oil were studied on the various ashes. As a result pistachio hull ash may be considered for the bleaching of the vegetable oils since its bleaching efficiency (57.8%) is close to Bentonite EY-09 (67.4%).
ABSTRACT Bleaching earths activated with acid are usually used to be removed non- triglyceride compounds (impurities) present in crude sunflower oil in industry. In this study the ashes of the pistachio, hazelnut and rice hulls instead of bleaching earth were used for the purpose of study their applicability by means of carbon and oxygen compounds in them. Bleaching kinetics and the adsorption isotherm were studied by determining the adsorption capacities of these hulls. The ashes obtained by the carbonization of these hulls at the temperatures of 200, 300, 400, 500, 600, 700, 800, 900 and 1000°C showed that the increment of in the bleaching efficiency (BE%) was due to leaching of colorizing matters and impurities. An optimum absorbance value was obtained for pistachio hull at the carbonization temperature of 600°C rather than the ashes of rice and hazelnut hulls. Thus it was shown that the dark color of crude oil converted to light color as the absorbance values decreased. Here the rate of the bleaching process obeys to that A r equation: log- - = -kvt A0 The absorbance measurements were carried out for bleaching of sunflower oil at the experimental temperatures of 30, 40, 50, 60, 70, 80 and 90°C with pistachio ash carbonized at 600°C. The adsorption heat was found as -4.7653 kJ mol-1 where the minus sign shows that the heat evolves, and it was seen that the forces between the adsorbent and adsorbate seem to be Van der Waals forces since this vlaue was less than 20 kJ mol-1. Therefore this type of adsorption may be recognized as the physical or Van der Waals adsorption. On the other hand, it was seen that the Freundlich equation was more applicable than the Langmuir equation to when the adsorption isotherms for the bleaching of sunflower oil were studied on the various ashes. As a result pistachio hull ash may be considered for the bleaching of the vegetable oils since its bleaching efficiency (57.8%) is close to Bentonite EY-09 (67.4%).
Açıklama
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Yüksek Lisans
Yüksek Lisans
Anahtar Kelimeler
Kimya, Chemistry
