The widespread presence of endocrine-disrupting emerging contaminants, such as ethylparaben (EtP), in aquatic environments presents mounting ecological and public health challenges. This study introduces an optimized Fenton–CaO₂ system enhanced with condensed tannins (DHB-type ligands) derived from pine bark and regulated through polymeric pH-control materials. Among these, a commercial resin proved most effective at maintaining stable pH, facilitating consistent hydroxyl radical (•OH) generation under mild conditions. A quaternized biopolymer also showed strong buffering potential, demonstrating the system’s potential for more sustainable biopolymer-based designs.
A systematic experimental design identified optimal removal conditions: 400–600 mg/L tannins, 200 μM Fe(III), and ≥2 mM CaO₂, achieving up to 98% EtP degradation (below the detection limits). The predictive model exhibited high reliability (R² ≈ 0.92), and residual by-products were minimal, as shown by HS‑SPME‑GC/MS analysis. These results confirm that combining pine bark–derived ligands with polymeric pH-control materials significantly enhances both efficiency and sustainability of Fenton–CaO₂ processes. This work presents a practical, environmentally friendly, and effective strategy for minimizing persistent contaminants in wastewater, emphasizing the importance of polymer integration as a crucial step toward future scale-up and deployment.