CTAB-modified Moroccan illite for sustainable removal of anionic and cationic dyes from simulated dye solutions: integrating experimental optimization and computational analysis

Synthetic dyes in wastewater pose significant environmental risks, necessitating innovative removal solutions. This study explores the adsorption of Acid Orange 7 (AO7) and Basic Yellow 87 (BY87) onto cetyltrimethylammonium bromide (CTAB)-modified Moroccan illite clay. The modified clay demonstrated enhanced adsorption properties, achieving maximum adsorption capacities of 152.19 mg/g for AO7 and 129.68 mg/g for BY87 under optimal conditions (pH 6.5, solid–liquid ratio of 3 g/L, and a contact time of 30 min). Characterization techniques, including CEC, XRD, XRF, SEM, Raman, and BET, confirmed the structural and surface modifications responsible for improved efficiency. Adsorption data were best fitted by the Langmuir isotherm model and pseudo-second-order kinetic model, indicating monolayer adsorption on homogeneous active sites. Thermodynamic analysis revealed exothermic and spontaneous processes, with ΔH° = − 23.50 kJ/mol (AO7) and ΔH° = − 24.59 kJ/mol (BY87). Response Surface Methodology (RSM) and Artificial Neural Network (ANN) models optimized the process, achieving high predictive accuracy (R² > 0.98). Quantum chemical calculations using Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations elucidated molecular interactions, such as electrostatic forces, hydrogen bonding, and π-π interactions between dyes and the modified clay surface. This comprehensive study bridges the potential of CTAB-modified illite clay as a high-performance adsorbent for industrial wastewater treatment, bridging theoretical insights and practical applications. By addressing synthetic dye pollution, the findings contribute to sustainable development goals (SDGs), including clean water and sanitation (SDG 6), responsible consumption and production (SDG 12), and climate action (SDG 13).