Microstructural and CO2 chemisorption analyses of Li4SiO4: Effect of surface modification by the ball milling process

Abstract

The ball milling process was used to modify microstructurally the Li4SiO4, and different structural and microstructural analyses were performed, followed by an analysis of the CO2 chemisorption process. In comparison to previous reports, the Li4SiO4 modified sample exhibited very important differences and improvements during the dynamic CO2 chemisorption process. Additionally, an analysis of the Li4SiO4–CO2 chemisorption products showed that the Li2CO3–Li2SiO3 external shell exhibits a degree of mesoporosity at T<500°C, which is favorable for diffusion processes. Finally, the CO2 chemisorption–desorption process was analyzed at 550°C during 10 cycles. The ball milled Li4SiO4 sample showed a stable performance during the CO2 chemisorption–desorption test and presented better efficiencies than the solid-state sample. The mechanical milling technique proved to be an effective method for modifying the microstructural properties of the ceramic absorbent by enhancing the CO2 chemisorption–desorption process without further sintering effects.