Obtención de nanocelulosa a partir de la hoja de mazorca de maíz (Zea mays L.) mediante el proceso de hidrólisis ácida

Abstract

The aim of the present research was to obtain nanocellulose from corn cob leaves. First, cellulose was extracted through 6 experiments that consisted of subjecting the cob leaves to physical and chemical treatments (alkaline treatment and bleaching), two variables were used in the alkaline treatment step: sodium hydroxide concentration and extraction temperature, keeping the fiber / liquor ratio constant (1:20) and extraction time of 2 hours. Subsequently, the morphological and chemical characterization of the celluloses was carried out, as well as a statistical analysis of the quantitative results, identifying that the E5 experiment obtained better results, with a yield of 38.94% and an alpha cellulose content of 91.51%. To obtain the nanocellulose, 2 methods were used: in the first, acid hydrolysis was applied with concentrations of sulfuric acid at 60% and 65%, keeping the fiber / acid ratio constant at 1:20, at 45 ° C and for 45 minutes, which was combined with ultrasound treatments; while in the second method only ultrasound treatments were used. The samples obtained were dried in the environment and characterized, determining that the nanocellulose with the best characteristics was that obtained with 65% sulfuric acid, which presented a Transmittance value of 90.779%, optical microscopy and SEM analysis confirmed the presence of nanocellulose structures with diameters between 10 and 50 µm, and infrared spectroscopy confirmed the presence of cellulose's own functional groups. It is recommended in the extraction of cellulose to carry out experiments with higher concentrations of sodium hydroxide to corroborate the complete elimination of lignin and hemicellulose. Regarding nanocellulose for its characterization, it is recommended to use other drying methods such as lyophilization or spray drying to avoid fiber agglomeration to a certain extent.