Optimization of preparation of cellulose nanocrystals from peanut shells using response surface methodology

Abstract

The value of peanut shells as agricultural wastes can be increased by recycling and utilizing these waste shells for the production of nanomaterials. To achieve this purpose, this study prepared cellulose nanocrystals from peanut shells by sulfuric acid hydrolysis. The central composite design based on the response surface methodology was applied to study the effects of sulfuric acid concentration, reaction temperature and reaction time on the yield of cellulose nanocrystals and the regression model was established between the yield and three factors. The results showed that the yield of the cellulose nanocrystals was 44.94%, under the optimum conditions of 64.6% of sulfuric acid concentration, 49.5°C of reaction temperature and 28.5 min of reaction time. The morphology and crystallinity index of cellulose nanocrystals were examined by transmission electron microscopy and X-ray diffraction. Transmission electron microscopy showed that cellulose nanocrystals presented a rod-shaped nature with the diameter ranging from 5 to 25 nm. X-ray diffraction indicated that cellulose nanocrystals were the type of cellulose I pattern, with a crystallinity of 74.71%.