Research on Synchronous Synthesis of Schwertmannite for Removal of Pb2+ from Acidic Wastewater

Schwertmannite (Fe8O8(OH)8−2x(SO4)x), an iron oxyhydroxysulfate mineral prevalent in acidic mining environments, demonstrates exceptional heavy metal adsorption capacity owing to its high surface area and abundant functional groups. This study developed a novel one-step synthesis method that simultaneously generates schwertmannite and removes Pb2+ from aqueous solutions, contrasting with conventional two-step approaches. Systematic investigation of operational parameters revealed that Pb2+ removal efficiency exceeded 98% across concentrations of 0~300 mg·L−1, with optimal performance at nSch:nPb ratios ≥ 2, pH 3.0~6.0, and 35 °C. Characterization studies identified four primary removal mechanisms: electrostatic adsorption, ion exchange, coordination complexation, and coprecipitation. The in situ method demonstrated significant advantages in processing efficiency, removal stability, and environmental sustainability compared to traditional approaches.