Enhanced remediation of naphthalene from aqueous solutions using synthesized organoclay: characterization, mechanisms, and isotherms.

Water contamination by polycyclic aromatic hydrocarbons (PAHs), particularly naphthalene, is a serious environmental concern due to its persistence, bioaccumulation, and toxicity. This study explores the adsorption behavior of naphthalene using organobentonite (OBt), synthesized by intercalating cetyltrimethylammonium bromide (CTAB) into sodium bentonite (SBt) with varying cation exchange capacities (CECs). The effectiveness of OBt in naphthalene adsorption was evaluated by analyzing key parameters, including CEC, contaminant concentration, and contact time. The morphological and structural properties of all adsorbents were characterized before and after the adsorption process. The results demonstrated a significant improvement in the adsorption capacity of OBt compared to SBt, with a maximum naphthalene adsorption capacity of 14.08 mg/g at 2.0 CEC, versus 5.22 mg/g for SBt. The Freundlich isotherm model provided the best fit for adsorption data (R > 0.97), indicating that the partitioning mechanism primarily governed the process. CTAB-modified OBt showed enhanced hydrophobicity, larger basal spacing, and faster adsorption kinetics, with most naphthalene removal occurring within the first 15 min. These findings indicated that OBt, due to its improved adsorption efficiency, rapid kinetics, and cost-effectiveness, is a promising adsorbent that can enhance the remediation of hydrophobic organic pollutants from contaminated water.