Abstract

The presence of synthetic dyes in industrial effluents, such as methylene blue, represents a significant environmental challenge due to their persistence and resistance to conventional treatment. This study evaluated a Fenton-like catalyst synthesized from iron recovered from acid mine drainage originating from the Quiulacocha tailings in Peru, with the aim of degrading methylene blue in a fixed-bed reactor. Iron was selectively precipitated (pH 2.5–4.0), converted into ferric hydroxide, thermally transformed into hematite (α-Fe₂O₃), and supported on liparite. The catalytic performance was evaluated using a Taguchi L8 experimental design considering pH (3.5–5.0), temperature (40–50 °C), hydrogen peroxide concentration (0.15–3.00 g/L), and flow rate (0.006–0.010 L/min). Results showed that the acid mine drainage, characterized by a high iron concentration, enabled the synthesis of a catalyst containing 46.84% to 52.83% iron, suitable for heterogeneous Fenton-like oxidation. Optimal degradation of methylene blue was achieved at pH 3.5, 50 °C, 3 g/L hydrogen peroxide, and a flow rate of 0.006 L/min, reaching removal efficiencies of up to 90.3%. Main-effect and interaction analyses confirmed that pH, temperature, and flow rate were the most influential factors. These findings demonstrate that materials derived from acid mine drainage constitute efficient, economical, and sustainable alternatives for the treatment of dye-contaminated industrial wastewater.