The effect of pKa on Kd is also significant. At low pKa values (~ -4 to 0), Kd remains low, suggesting weaker adsorption due to the adsorbate being in a highly ionized state. As pKa increases, Ka rises, indicating stronger hydrophobic or π-π interactions. The curvature of the surface plot highlights the interactive effect of surface area and pKa, suggesting that adsorption efficiency depends on achieving an optimal balance between these two factors. Simply increasing surface area does not guarantee higher adsorption, emphasizing the need to optimize both adsorbent properties and chemical interactions for effective contaminant removal. At moderate surface area (~1000-1500 m²/g) and temperature (~30-40°C), Kd reaches its maximum, suggesting that an optimal combination of surface properties and thermal conditions enhances adsorption. However, beyond ~1500 m²/g surface area and above ~40°C, adsorption efficiency declines, likely due to desorption effects, decreased adsorbate-adsorbent interactions, or structural changes in the adsorbent material. The surface plot highlights the interactive nature of surface area and temperature, reinforcing that excessively high temperatures may weaken adsorption forces, while extreme surface area values may not always improve adsorption due to diffusion limitations or reduced active site accessibility.