Biorefinery of lignocellulosic materials: novel products, methods and applications of forest and agricultural feedstocks

• Ano de defesa: 2015
• Autor(a) principal: Silva, Juliana Cristina da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Milho - Aplicações industriais; Biomassa vegetal; Papel - Avaliação; Celuloses; Hemiceluloses; Biofilme; Tecnologia e Utilização de Produtos Florestais
• Link de acesso: http://www.locus.ufv.br/handle/123456789/21924

Currently, the diversification in product portfolio and optimization of techniques and processes have become a concern formany industries that are seeking raw materials from renewable and biodegradable sources. Biorefineries of forest and agricultural products stand out as templates that allow obtaining greater value for products from lignocellulosic biomass. Thus, within the concepts of biorefinery, this thesis aimed toexplore the lignocellulosic biomass from forest and agriculture to improve quality and technology of widely used products, such as paper. In addition, it sought to produce materials that can replace oil-based products such as plastics, with the production of biofilms. Furthermore, the production and characterization of aerogels was performed, and into the wide range of their applications, their potential was evaluated for water treatment to remove heavy metals. Nanocelluloses, microfibrillated cellulose (MFC), nanofibrilada cellulose (NFC) and cellulose nanocrystal (CNC), along with the xylan- rich in hemicelluloses have been exploited and employed to achieve the objectives of this study, presented in the form of chapters. In the first chapter, xylan -rich hemicelluloses were extracted from corn cobs and added in cellulosic pulps. The increased concentration of hemicellulose led to an increase in drain resistance and in paper properties directly affected by the inter-fiber bonds. The paper bulk was inversely proportional to the addition of hemicelluloses. In the second chapter, hemicelluloses extracted in the same way as in Chapter 1 were used for the production of biofilms. The hemicelluloses were subjected or not to acetylation processes. The biofilms were reinforced with agents as nanofibrillated cellulose (NFC), polyamine- epichlorohydrin resin (PAE) and some plasticizers. The results showed that it is possible to produce films from hemicelluloses and that when these carbohydrates were acetylated, the films showed higher tensile index and greater strain. Another important feature was the hydrophobicity of the films after acetylation. All films showed high air resistance. In the third chapter, the nanocelluloses were added to unbleached pulp from Pinus, refined at different intensities. The results showed that the handsheet properties related to increased inter-fiber bonds increased with the incorporation of nanoceluloses, and the incorporation of the MFC demonstrated greater increases compared to the reference pulp. In Chapter 4, aerogels formed from NFC reinforced with xylan -rich hemicelluloses were characterized. The results showed that NFC:xylan ratio affects the shape, strength, surface area and water absorption capacity of aerogels. Finally, the aerogels described in Chapter 4 were assessed for the ability to remove heavy metals from aqueous solutions. The results showed that the aerogels exhibit high adsorption capacity for metal ions Zn 2+ , Pb 2+ and Cd 2+ . Aspects such as formulation, pH, initial concentration and contact time influenced the adsorption capacity of the aerogels.