This study investigates the preparation and characterization of cellulose nanofibrils (CNF) derived from hardwood bleached kraft pulp (HWBK) through an oxidation and homogenization process. The HWBK was treated according to a Fenton process using ferrous sulfate (FeSO₄·7H₂O) to enable Fe²⁺ ions to adsorb and diffuse into the pulp fibers. Subsequently, hydrogen peroxide (H₂O₂) was introduced to initiate an oxidation reaction catalyzed by the embedded Fe²⁺ ions, facilitating the breakdown of the fiber structure. The oxidized fibers were then thoroughly washed and subjected to PFI mill refining to produce a uniform CNF dispersion. The properties of the CNF dispersion, including its viscosity, were assessed to determine the extent of nanofibrillation. Characterization techniques such as polarized optical microscopy and charge density test were employed to analyze the morphological and chemical features of the resulting CNF. The findings demonstrate a successful preparation of CNF from HWBK, with potential applications in various nanocomposite and biodegradable materials. The project is still ongoing and other characteristic test such as energy-dispersive X-ray spectroscopy (EDS) and AFM are in the target. Results will be discussed in relation to other CNFs, especially those using Fenton chemistry.