OBTENÇÃO E CARACTERIZAÇÃO DE NANOCELULOSE COM O USO DE SAIS INORGÂNICOS COMO AGENTES CATALISADORES DA HIDRÓLISE ÁCIDA

Abstract

The search for new materials has been characterized by the development of more sustainable processes, such as the use of renewable raw materials and the production of non-aggressive composites to the environment, without loss of quality or performance. Obtaining nanocellulose from vegetable fibers and residues is an example of this new view that has been intensively investigated because of its high crystallinity and specific surface area properties. However, in order to obtain these cellulose nanocrystals, the amorphous regions present in the lignocellulosic material must be digested by the hydrolytic cleavage of the glucose bonds, thus leaving only the regions of high crystallinity. The most common process is acid hydrolysis consisting of the use of solvents such as sulfuric acid and hydrochloric acid, but the strength of the hydrolysis can lead to uncontrolled depolymerization of the cellulose resulting in undesirable products. The inorganic salts FeSO4, Fe2 (SO4)3, FeCl3, were used as a catalyst for the hydrolysis process, once they react with water and release the H3O hydronium, increasing the acidity of the solution. In this way, the influence of the parameters salt concentration and reaction time were evaluated and the conditions optimized to obtain nanocellulose with maximum yield or with high crystallinity were determined.Thus the nanocellulose was obtained by hydrolysis with inorganic salts and presented in the majority of crystallinity increase (91.73%) and yield (76.2%). Therefore, it is an alternative solution, since the use of inorganic salts presents less acidity and therefore are less corrosive and less severe, besides having less environmental impact.