A systematic review on the uses of red mud as feedstock to make catalysts, coagulants and conditioners for treatment of contaminated water

Abstract

For the past decades, great efforts have been made to beneficially utilize red mud, a hazardous waste material from alumina refining. These include recovery of valuable metals, use as feedstock for making construction materials, and various environmental applications. There have been numerous review articles that evaluated and analyzed the published literature on the adsorption application of red mud for treating contaminated water. However, little effort has been made to synthesize the existing knowledge on red mud application as the feedstock for making coagulants, catalysts, and conditioners despite that there has been increasing published reports on these aspects. To fill this knowledge gap, a systematic review was conducted by initially screening relevant journal articles published within the last 10 years (2015-2025) and subsequently critically analyzing and evaluating the selected articles. The results showed that there was a clear trend that the published work on catalyst application increased over time, especially in the recent 5 years while the published work on coagulation and conditioner applications fluctuated. Red mud-derived catalysts were applied in different types of advanced oxidation processes, mainly including photocatalysis, conventional Fenton oxidation, photo-Fenton oxidation, electro-Fenton oxidation and persulfate oxidation. Through this systematic review, the challenges for red mud applications in making catalysts, coagulants and conditioners were identified and recommendations for further research are made accordingly.

Keywords: Catalyst; Circular economy; Coagulant; Conditioner; Red mud; Wastewater.