Effect of biomass pretreatment conditions on the glucose and biodegradable film production from lignocellulosic wastes

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: ERİNÇ BAHÇEGÜL

Danışman: NECATİ ÖZKAN

Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu

Özet:

Process parameters during the conversion of lignocellulosic agricultural wastes including corn cobs and cotton stalk into glucose and biodegradable polymeric materials were investigated. The investigated parameters were pretreatment type, pretreatment temperature, lignocellulosic biomass particle size prior to pretreatment, hemicellulose extraction temperature, salt type, salt concentration and polymer processing technique. Pretreatments applied to corn cobs including dilute acid, alkaline and ionic liquid pretreatments gave similar glucose yields (73 – 84%) upon enzymatic hydrolysis where the lowest and highest glucose yields were obtained for dilute acid and ionic liquid pretreatments, respectively. The ionic liquid pretreatment efficiency was shown to depend on the lignocellulosic biomass particle. 1-ethyl-3-methylimidazolium chloride functioned more efficiently at smaller biomass particle sizes (<0.15 mm and 0.15 – 0.5 mm) compared to larger ones (0.5 – 1.0 mm and 1.0 – 2.0 mm), while opposite was true for the ionic liquid 1-ethyl-3-methylimidazolium acetate in terms of glucose production. During the co-production of glucose and hemicellulose based films, the hemicellulosic part of the process, which is related to the film production, was shown to be much more sensitive to the changes in the alkaline pretreatment temperature compared to the cellulosic part of the process that considers glucose production. It was also shown that the salt potassium acetate, which can be found together with hemicelluloses, was beneficial for the films. Finally extrusion was used as a new processing technique for the hemicellulose based polymers where the produced materials showed an ultimate tensile strength of 76 MPa and an elongation at break of 35%.