Waste from an Amazon Mining Company Applied as a Catalyst in Photocatalysis Reactions for Environmental Remediation

The environmental problem caused by mining companies is known and has been studied by several authors. In this work, a sustainable solution was sought for iron-based waste collected from a mining company. This waste was purified and synthesized as a promising catalyst for degradation of polluting compounds, using methylene blue as a test. The sol–gel synthesis route was efficient for the removal of unwanted residues and for the formation of the α-Fe 2 O 3 product. The material after sol–gel reached about 95.6% of degradation of the methylene blue solution (20 mg L −1 ), this response that can be attributed to a more porous and less compacted morphology and the presence of a more organized phase. This work assigns a sustainable purpose for iron waste, accumulated in mining companies, and shows that these materials can be as efficient for environmental remediation, as those contained in the literature. Highlights Purification and sol–gel synthesis of mining waste. Use of mining waste as catalysts for advanced oxidative processes. A sustainable purpose for the environmental problem caused by mining companies. Graphical abstract