Transforming waste red mud into sustainable cementitious materials for self-cleaning applications

The development of novel catalysts and photocatalytic materials is an active area of study in the field of remediation of air pollution. The aim of this study is to investigate the potential of red mud-based cement mortars for photocatalytic abatement of nitrogen oxides (NO and NOx) under solar irradiation. Red mud is an industrial by-product generated during the Bayer process for refining bauxite into alumina. It poses significant environmental challenges due to its highly alkaline nature and presence of toxic heavy metals. Typically, hematite (α-Fe2O3) and goethite (α-FeOOH) are the compounds or iron oxide phases which are found in abundance in red mud. Interestingly, hematite is a nontoxic and stable compound, which possesses a visible light active band gap and can be a potential catalyst for photocatalytic activity.