Self-healing water-soluble styrene-acrylic emulsion for efficient tailings passivation

Acid mine drainage (AMD) from sulfide-rich tailings remains a pressing environmental issue, necessitating sustainable solutions to inhibit sulfide oxidation. This study introduces a novel green-synthesized water-soluble and self-healing phosphate ester-modified styrene acrylic emulsion (PESA/Ce(dbp) 3 ) for tailings passivation, synthesized without organic solvents via aqueous emulsion polymerization. The formulation incorporates 2-hydroxyethyl methacrylate phosphate (PAM-100) as a functional monomer and cerium dibutyl phosphate (Ce(dbp) 3 ) as a pH-responsive self-healing agent. Characterization (SEM, FT-IR, XPS) confirmed the formation of a hydrophobic, crosslinked passivation film on pyrite surfaces, stabilized by covalent P-O-Fe bonds. Electrochemical analysis revealed that the optimized PESA-0.5/Ce(dbp) 3 -0.15 formulation reduced corrosion current density by 96 % and achieved 85.3 % Fe 2+ and 73.1 % SO 4 2− passivation efficiencies over 24 h. The self-healing mechanism involves Ce(dbp) 3 decomposition at defect sites, generating CeO₂ nanoparticles and iron-phosphate complexes to repair film integrity. As a new type of tailings passivation agent, PESA-0.5/Ce(dbp) 3 -0.15 has the advantages of green synthesis (no organic solvent), room temperature film formation, high adhesion, high efficiency blocking oxidation, pH response self-healing, low cost, etc., which is suitable for the sustainable treatment of AMD at source.