Effect of doping K element on properties of lithium silicate as CO₂-absorbent

Using Li₂CO₃, SiO₂, and K₂CO₃ as the starting materials, potassium-doped lithium silicate absorbents were prepared by high-temperature solid-state reaction. The influence of doping potassium on the crystal structure of the prepared absorbents was studied by comparison of their XRD patterns. The microscopic morphologies of absorbents with different K₂CO₃ content were viewed by sanning electron microscopy. Their CO₂-absorption abilities were measured with a thermogravimetric analyzer. The experimental results showed that doping of potassium could improve appreciably the CO₂-absorption ability of lithium silicate. It was found that lithium silicate absorbed as much as about 48% (weight ratio) of CO₂ under CO₂ atmosphere at 700°C within 15 min.