Bagasse modification of red mud for efficient photocatalytic degradation of real dye wastewater: An utilization attempt for massive waste

The high concentration of metal compounds found in red mud (RM) can serve as cost-effective raw materials for photo Fenton catalysts in the treatment of organic dye wastewater. In this study, RM was modified with bagasse using a hydrothermal method to prepare a photo-Fenton catalyst. The degradation efficiency of Rhodamine (RhB) solution under different conditions was evaluated. In a reactive system with a catalyst concentration of 1 g/L, RhB concentration of 20 mg/L, reaction pH of 6.1 and H2O2 concentration of 0.0485 mol/L, the degradation rate of RhB reached 86.88% after 110 min of reaction. RhB exhibited a consistently high degradation rate across 6 experimental cycles. Toxicity experiments confirmed that the concentration of heavy metal ions in the liquid phase fell within national standards. Real dye wastewater was tested under natural sunlight, with results indicating a 64.31% reduction in COD(Chemical Oxygen Demand) and a 47.63% decrease in TOC(Total Organic Carbon) after 220 min of treatment. The biodegradability of dye wastewater had also been significantly improved. These findings strongly support the green and sustainable development of the printing and dyeing industry, which also offer important solutions for the utilization of massive industrial solid waste and agricultural solid waste. [Display omitted] •Industrial and agricultural solid waste of red mud and bagasse are used to prepare photo-Fenton catalyst (M-RM).•M-RM exhibits excellent stability and recovery.•M-RM is effective for degrading real dye wastewater under solarlight.••OH, O2●−, 1O2, and h+ are responsible for dye wastewater degradation.