TEMPO-Oxidized Nanocellulose from Sargassum as a Sustainable Material for the Removal of Salicylic Acid in Water

This work presents the extraction of cellulose from Sargassum and its subsequent conversion into cellulose nanofibril (CNF) using the TEMPO oxidation method. Structural and surface characterizations (XRD, FTIR, FESEM, EDS, AFM, and XPS) confirmed the synthesis, purification, and functionalization of CNF. Compared to purified cellulose (CP), the CNF exhibited higher crystallinity and significantly higher functionalization, particularly with carboxy groups. These carboxy groups played a crucial role in the interaction between cellulose fibers and salicylic acid. UV-Vis and FTIR analyses confirmed the removal of salicylic acid (SA) from water, with only CNF demonstrating effective absorption. UV-Vis analysis showed increased absorption at wavelengths < 250 nm due to interactions between cellulose fragments and SA. To avoid this interference, the adsorption efficiency was determined following the band at 296 nm, where 90% removal of salicylic acid was achieved after 48 h. These findings suggest that NFC from waste biomass is a promising material for water remediation.