Effects of modification and calcination conditions on the adsorption performance of red mud for low-concentration formaldehyde in air

The effects of modification and calcination conditions on the performance of red mud (RM) to absorb low-concentration formaldehyde in air were investigated using a fixed-bed flow reactor. The results show that the adsorption of RM for formaldehyde increases upon decreasing calcination temperature, with the optimum calcination temperature of 300 °C. H ₂O₂ modification can improve the adsorption performance, with the optimum modification concentration at 20 wt. %. Pore structure analysis indicated that low-temperature calcination improves the formation of micropores (0.9 nm to 2.7 nm), and maximizes the specific surface area and total pore volume thereby facilitating formaldehyde adsorption.