Hence, XGB also confirms the overarching trend that Initial Concentration and Surface Area are pivotal to predicting Kd, with pHpzc, pH, and other chemical descriptors playing smaller but nonnegligible roles. pHpzc and pH are also significant, especially in Random Forest, implying that surface charge conditions strongly influence PFAS binding. Molecular descriptors like pKa, Log Kow, and Molecular Weight provide mid-range importance, indicating that hydrophobicity, ionization, and molecular size can further modulate adsorption.