Iron‐modified natural sand as a heterogeneous Fenton catalyst for methylene blue and textile wastewater treatment

BACKGROUND The continuous discharge of organic dyes into freshwater poses long‐term environmental risks. Heterogeneous Fenton‐like processes using iron (Fe)‐modified silica (SiO 2 ) supports are promising for dye removal; however, catalysts derived from natural sand and operating under near‐neutral conditions remain relatively underexplored. This study investigates Fe‐modified Tunisian natural sand (Si‐Fe) as a potentially low‐cost catalyst for methylene blue (MB) removal and textile wastewater treatment. RESULTS The Fenton‐like process was optimized using response surface methodology based on a four‐factor Box–Behnken design. The optimal conditions were initial MB concentration 5 mg L −1 , Si–Fe dose 0.745 g L −1 , pH 7.9 and H 2 O 2 dose 5 mL L −1 , yielding a predicted MB removal efficiency of 95.31%. The catalyst maintained a removal efficiency >83% over five reuse cycles. In real textile wastewater treatment, the process achieved >99% color removal, ≈70% COD reduction and >84% turbidity reduction. CONCLUSION The results demonstrate the potential of Si–Fe, prepared from naturally abundant Tunisian sand, as a durable and potentially low‐cost heterogeneous Fenton‐like catalyst for MB removal and textile wastewater treatment, including under near‐neutral conditions.