OICC Press International Journal of Nano Dimension 2228-5059 17 1 2026 01 02 A Novel Hazelnut Shell/Magnetite Bio-Nano adsorbents for Enhanced Oil Removal From Oil-Contaminated Waters 10.57647/j.ijnd.2026.1701.05 EN Ulkar Nuru Naghiyeva Baku State University, Department Ecological Chemistry, AZ1148, Z.Khalilov 23, Baku, Azerbaijan Sevinc Rafik Hajiyeva Baku State University, Department Ecological Chemistry, AZ1148, Z.Khalilov 23, Baku, Azerbaijan Flora Vidadi Hajiyeva Baku State University, Department Chemical Physics of Nanomaterials, AZ1148, Z. Khalilov 23, Baku, Azerbaijan; Baku State University, Nano Research Center, AZ1148, Z. Khalilov 23, Baku, Azerbaijan https://orcid.org/0000-0003-1686-3401 Luca di Palma Sapienza Universita` di Roma, Dipartimento di Ingegneria Chimica Materiali Ambiente, Via Eudossiana 18, 00184 Rome, Italy Irene Bavasso Maria Paola Bracciale Sapienza Universita` di Roma, Dipartimento di Ingegneria Chimica Materiali Ambiente, Via Eudossiana 18, 00184 Rome, Italy Journal Article 2026 01 02 The primary objective of this study is to evaluate the feasibility of using hazelnut shells as a biosorbent for the cleanup of oil and petroleum product spills in water bodies. The effects bioadsorbent, nanoparticle concentrations, oil concentration, temperature (10-4000C), and pH on oil adsorption were investigated to determine the optimal conditions for maximum purification efficiency. The highest oil removal efficiency achieved with the biosorbent was 61.25% at a pH of 7.5. To enhance the sorption capacity of the biosorbents were synthesized by incorporating Fe₃O₄ superparamagnetic nanoparticles at concentrations of 1%, 3%, 5%, and 10%. Characterization of both the biosorbents was conducted using SEM, TGA, and FTIR analyses to assess the interaction between Fe₃O₄ nanoparticles and the plant-derived surface of the biosorbent. For an adsorbent such as hazelnut shell+Fe₃O₄ bio-nanoadsorbent, the pHzpc indicates the point at which the surface of the bio-nanoadsorbent changes from negatively charged to positively charged as the pH of the solution increases or decreases. The zero-charge pH point of the bio-nanoasorbent was determined to be pH=8 by Boehm titration. The optimal adsorption conditions for the bio-nanosorbent, composed of hazelnut shell and 10% Fe₃O₄ nanoparticles, were found to be 92.5% oil removal within 12 minutes at a pH of 7.5.