Cellulose is an abundant renewable natural material with good properties, being soft, ecofriendly, machinable, cheap, and remarkably hydrophilic, making it an attractive support for nanoparticles. Cellulosic biomaterials have good adsorption potential due to the presence of hydroxyl functional groups. Based on the dimension and morphology, nanocellulose is grouped as cellulose nanocrystals (CNC), cellulose nanofibers, (nanofibrillated cellulose) and bacterial cellulose. Cellulose nanofibers can be obtained from various cellulosic sources, such as oil palm biomass, wood pulp, bamboo, rice straw and many more. Sugar palm fiber and palm kernel shell are one of the prospective fibers that had been explored for its capability to reinforce composites with other polymers. Usually, sugar palm fiber has no commercial potential since it is considered as an agricultural waste.

Sugar Palm fiber has the potential to be synthesized into nanofiber because it contains high enough cellulose, about 40-60%. The synthesis of nanofibers was carried out by chemo-mechanical methods. Chemical processes included delignification by alkali, acid hydrolysis, and bleaching. Meanwhile, the mechanical process consisted of grinding. Modifications were also made to the formed nanofibers, namely nano oxide coating.

Palm fiber waste has been successfully utilized as a nanofiber adsorbent. It was indicated by the presence of functional groups forming cellulose, namely OH groups, C-O groups, and C-H groups in the three synthesis products. In addition, the coating of iron oxide (Fe3O4) on nanofibers has also been successful, as revealed by the presence of Fe-O functional groups in the range of 700 cm-1, namely at the peaks of 529.48 cm-1 and 445.58 cm-1. In addition, the mean size of the resulting nanofiber was 33.902 nm, and the best degree of crystallinity for the nanofiber without coating was 74.933.

Moreover, the addition of an iron oxide (Fe3O4) coating could increase the adsorption capacity. However, this adsorbent was more optimal for absorbing basic dyes (MB) than acid dyes (CR). Due to the acidic conditions, it would allow the release of Fe residues into the solution. It is because if the acidity is high, H+ ions will react with Fe3O4 and cause the release of Fe ions into the solution