Performance and mechanism of modified red mud for the toluene adsorption

The adsorption process is important for the gas-solid catalytic reactions. Therefore, it's of great significance to investigate material adsorption performance for the gas-solid catalysis. In this paper, toluene adsorption was investigated through the adsorption penetration curves of RM, MRM and 0.3Pd-MRM at different temperatures. The results showed that 0.3 wt% Pd-MRM had the best toluene adsorption performance, which was attributed to the optimization of the pore structure of the red mud by acid modification, and the loading of metal to increase the toluene adsorption sites. The pseudo-first order model (PFO) could be fitted the adsorption rate curves well, indicating that the toluene adsorption process on red mud particles was primarily driven by the physical adsorption. The Boyd's film-diffusion model and mass transfer model collectively indicated that internal diffusion played a pivotal role in the toluene adsorption process of MRM and 0.3Pd-MRM. In addition, 0.3Pd-MRM exhibited stronger resistance to internal diffusion that was attributed to the presence of Pd, which led to the stronger toluene force on red mud surface.