Production of cellulose nanocrystals from pineapple crown fibers through alkaline pretreatment and acid hydrolysis under different conditions

In the growing search for sustainability, nanocellulose has stood out, since it is obtained from natural fibers, a renewable and biodegradable source, being able to promote the reuse of agricultural waste. Due to their high availability and low cost, residues from pineapple consumption become a viable alternative for the nanocellulose production process, which has not been explored so far. In this sense, the work aimed to produce nanocellulose from pineapple crowns, via acid hydrolysis, promoting the study of different process conditions, to define which methods obtained better results. The fibers were pretreated by mercerizing with sodium hydroxide and bleaching with hydrogen peroxide and sodium hydroxide. This was followed by hydrolysis with sulfuric acid to obtain the nanoparticles. Chemical characterization and scanning electron microscopy were performed on the crude and bleached fibers, and transmission electron microscopy on the produced nanocellulose. The treatments were effective in reducing lignin and hemicellulose in the fiber, and microscopy proved the production of cellulose nanoparticles, with an average width equal to 10.38 nm. Therefore, the results confirmed the potential of the process used to obtain nanocellulose from the pineapple crowns.