Surface Adhesion of Atrazine onto MgO/Fe₃O₄: A Probabilistic and Topographic Study for Water and Soil Remediation

Using the grand canonical framework, we investigate the key physicochemical properties governing atrazine adsorption on MgO/Fe₃O₄-based porous carbon materials. Adhesion isotherms were modeled using theoretical frameworks aligned with experimental data through specific fitting metrics. Error metrics (R², RSS, R²_adj, and reduced χ²) support the monolayer, single-energy model as most representative of molecular-scale adsorption. The stereographic δ parameter (1.22-1.65 from 303-328 K) suggests atrazine adsorbs onto MgO/Fe₃O₄ in a non-horizontal molecular orientation. Retention energy, mainly from physical interactions (<40 kJ/mol), reaches 11.4 kJ/mol at 328 K. Disorder rises initially, marking void saturation, and then declines with higher atrazine levels, indicating increased surface organization. Fixation remains spontaneous and favorable at higher temperatures, as shown by a negative Gibbs energy and greater adsorption capacity. Our research also shows that the void diameter distribution curve presented a prominent peak centered around 2.1 × 10^-7 m, suggesting that mesopores played a major role in surface adhesion. As the temperature rises to 318 K (328 K), the void diameter peak shifts to smaller radii (∼1.95 × 10^-7 and ∼1.8 × 10^-7 m). At 303 K, binding energy peaks near 15 kJ/mol, indicating dominant adsorption energy. As the temperature rises to 318 and 328 K, the peak intensity of the binding energy distribution gradually decreases while remaining within the 15-17 kJ/mol range, supporting the predominance of physisorption as the underlying adsorption mechanism. Finally, a comparative table is provided to contextualize our findings within the existing literature, underscoring the high adsorption efficiency and promising applicability of MgO/Fe₃O₄ as a competitive support material for contaminant removal.