The catalytic effect of red mud on Vietnam anthracite’s combustion characteristics was investigated. The mineralogical composition of the red mud includes CaCO₃, Fe₂O₃, FeO(OH), FeTiO₃, and Al(OH)₃. This red mud is rich in Na, Ca, Al, Fe, and Ti. The combustion characteristics were analyzed by the thermogravimetry method. The combustion effectiveness was assessed by thermogravimetric analysis. The results were derived from a combination of several parameters, such as the ignition temperature, the burnout efficiency, and the amount of heat release. The combustion characteristics of pulverized coal were improved by the introduction of red mud, and the greatest catalytic performance was achieved when the content reached 6%. With the optimal addition, the ignition temperature of anthracite was reduced by 12 °C, and the burnout efficiencies were increased by 2.59% compared to raw anthracite. The amount of heat released by anthracite was increased to 6.93 kJ/g by adding red mud.

The mixture of three metal ions (Cs⁺, Sr²⁺, and Co²⁺) is commonly found in radioactive waste, which induces several negative health effects. The removal of multiple metal ions is a true challenge for researchers due to the competitive adsorption of ions onto adsorbents. In this study, three metal ions, namely Cs⁺, Sr²⁺, and Co²⁺, have been successfully removed simultaneously from water using zeolite@magnetic nanoparticles (Z@Fe₃O₄ NPs). The optimized condition for the adsorption of ternary metal ions was obtained at an adsorbent weight of 0.2, pH of 6.0~7.0, and contact time of 60 min. The adsorption mechanism of ternary metal ions onto the surface of Z@Fe₃O₄ NPs was studied using the Pseudo-first-order, Pseudo-second-order, Elovich, and Intra-particle diffusion models. The Dubinin–Radushkevich Temkin, Freundlich, and Langmuir isotherm models were used to study the isotherm adsorption. The ternary metal ion adsorption (Cs⁺, Sr²⁺, and Co²⁺) on Z@Fe₃O₄ NPs was followed by the Pseudo-second-order model (PSO) with correlation coefficient (R²) range of 0.9826–0.9997. Meanwhile, the adsorption isotherms of ternary metal ions on Z@Fe₃O₄ NPs were in line with the Langmuir model with R² values higher than 0.9206, suggesting monolayer chemisorption with maximum adsorption capacities of 48.31, 15.02, and 10.41 mg/g for Cs⁺, Sr²⁺, and Co²⁺, respectively. Thus, the selectivity trend in the ternary metal ions system towards the Z@Fe₃O₄ NPs is observed to be Cs⁺ > Sr²⁺ > Co²⁺, which indicates that the competitive effect of Cs⁺ is the strongest compared to Sr²⁺ and Co²⁺ions.