Decomposição do Reactive Black B via reação Fenton usando resíduo de ferro de mineração como catalisador

Abstract

Mining generates large amounts of waste associated with environmental pollution. In gold mining, there is the generation of iron waste, mainly during ore crushing and grinding processes. The application of new technologies to reuse mineral waste, thereby reducing environmental impacts, has been under study. Iron waste can be used in various applications, such as battery production, construction materials, concrete, and also as catalysts in environmental decontamination processes. A promising application for these iron mineral wastes is their use as a catalyst in advanced oxidative processes (AOP) for environmental decontamination. AOP, such as the Fenton process, is highlighted as efficient in removing contaminants, especially textile dyes. Water contamination by organic, inorganic, and pathogenic pollutants, with synthetic dyes being significant contributors, is a concern. Synthetic dyes widely used in various industries are resistant to photolytic and biological degradation, posing carcinogenic risks. Azo dyes, such as Reactive Black B (RBB), are of concern due to their prevalence in the textile industry and the associated risks in wastewater. Conventional wastewater treatment methods based on biological approaches may be ineffective due to the recalcitrant nature of dyes. Advanced oxidation processes, such as the Fenton method, provide a promising alternative for treating wastewater containing dyes. The objective is to evaluate the capacity of the iron waste generated in the mining process as a catalyst in the Fenton-type advanced oxidation process for degrading RBB dye, offering an alternative in removing these compounds from textile effluents. pH parameters (2, 3, 4, and 5) and H2O2 concentration (0.10%, 0.25%, 0.5%, and 1%) were evaluated. The residual concentration of RBB was determined by UV-Vis spectrophotometry (Hach DR6000). It was concluded that the mining iron waste showed efficiency in degrading RBB under conditions of 20 mgL-1 RBB, pH 2; 1 gL-1 iron waste, 1% H2O2 at 25 °C.