Ironstone Powder as a Novel, Effective, and Low-Cost Catalyst for Organic Compound Oxidation in Water by Photo-Fenton Route

Abstract Ironstone is a decorative stone widely used in landscaping projects. Due to the presence of iron in its structure, it presents itself as a potential material to be used as a catalyst in Fenton reactions. In this work, ironstone powder was first used as a photo-Fenton catalyst for the abatement of organic pollutants in water. Characterization techniques indicated that the material has a significant iron content (20 wt.%), being well distributed over the surface of the particles. The material was employed in the decomposition reaction of amaranth dye in water, reaching 95.38% removal in 70 min under visible light. Central composite rotational design (2 3 ) (CCRD) was employed to optimize the reaction process. Kinetic studies were developed in order to elucidate the behavior of the reaction. The material presented high catalytic efficiency after six reuse cycles. In summary, ironstone constitutes an alternative and promising catalyst for the abatement of dye molecules in an aqueous system.