Effect of cellulose nanoparticles from garlic waste on the structural, mechanical, thermal, and dye removal properties of chitosan/alginate aerogels

Aerogels with cellulose nanoparticles (CNP) from garlic waste in a chitosan/alginate matrix via a freezing process were prepared. Physicochemical, structural, thermal, and mechanical characterization were performed in aerogels revealing an enhancement in the water solubility, degree of swelling, mechanical and thermal properties, and dye removal when CNP were added. Scanning electron and confocal microscopy images showed an organized structure in a multilayer shape when CNP were added compared to aerogel without CNP. Since CNP act as a filler and mechanical reinforcement for the aerogel, improvements in their polymer matrix were evidenced using spectroscopy (FTIR, XPS, and XRD) and microscopic techniques, as well as their thermal and mechanical properties, degree of swelling, and dye removal capacity of methylene blue (MB). Aerogels with CNP provided better removal of MB (62%) in contrast with aerogels without CNP (45%), providing a material with better capacity to remove dye in water. The novelty of this work was revealing the role of the CNP addition into the aerogels’ structure using electron and confocal microscopy by detailed image analysis and staining selective with conventional fluorochromes, respectively.