Among the linear terms, the Surface Area (1.366, p = 0.002) shows a positive and statistically significant effect on Kd, suggesting that a larger surface area enhances adsorption capacity. Similarly, pHpzc (302.180, p = 0.031) has a positive effect, indicating that materials with a higher point of zero charge (pHpzc) tend to favor PFAS adsorption, likely due to stronger electrostatic interactions. pKa (14.909, p = 0.040) also exhibits a positive and significant influence, implying that the acid dissociation constant of PFAS compounds plays a key role in their adsorption behavior. The pH (-1315.724, p = 0.022) term is negative, indicating that increasing pH reduces Kd, which aligns with expectations since higher pH values can increase electrostatic repulsion between PFAS and the adsorbent surface.