Abstract: The world is currently facing the challenges of global warming and climate change. Numerous efforts have been taken to mitigate CO₂ emission, among which is the use of solid sorbents for CO₂ capture. In this work, Li₄SiO₄ was synthesised via a sol-gel method using lithium nitrate (LiNO₃) and tetraethylorthosilicate (SiC₈H₂₀O₄) as precursors. A parametric study of Li:Si molar ratio (1-5), calcination temperature (600-800℃) and calcination time (1-8 h) were conducted during sorbent synthesis. Calcination temperature (700-800℃) and carbonation temperature (500-700℃) during CO₂ sorption activity were also varied to confirm the optimum operating temperature. Sorbent with the highest CO₂ sorption capacity was finally introduced to several cyclic tests to study the durability of the sorbent through 10 cycles of CO₂ sorption-desorption test. The results showed that the calcination temperature of 800℃ and carbonation temperature of 700℃ were the best operating temperatures, with CO₂ sorption capacity of 7.95 mmol CO₂·(g sorbent)^-1 (93% of the theoretical yield). Throughout the ten cyclic processes, CO₂ sorption capacity of the sorbent had dropped approximately 16.2% from the first to the tenth cycle, which was a reasonable decline. Thus, it was concluded that Li₄SiO₄ is a potential CO₂ solid sorbent for high temperature CO₂ capture activity.

Key words: CO₂ capture, Adsorption, Carbon dioxide, Lithium orthosilicate, Sol-gel, Sorption-desorption

摘要： The world is currently facing the challenges of global warming and climate change. Numerous efforts have been taken to mitigate CO₂ emission, among which is the use of solid sorbents for CO₂ capture. In this work, Li₄SiO₄ was synthesised via a sol-gel method using lithium nitrate (LiNO₃) and tetraethylorthosilicate (SiC₈H₂₀O₄) as precursors. A parametric study of Li:Si molar ratio (1-5), calcination temperature (600-800℃) and calcination time (1-8 h) were conducted during sorbent synthesis. Calcination temperature (700-800℃) and carbonation temperature (500-700℃) during CO₂ sorption activity were also varied to confirm the optimum operating temperature. Sorbent with the highest CO₂ sorption capacity was finally introduced to several cyclic tests to study the durability of the sorbent through 10 cycles of CO₂ sorption-desorption test. The results showed that the calcination temperature of 800℃ and carbonation temperature of 700℃ were the best operating temperatures, with CO₂ sorption capacity of 7.95 mmol CO₂·(g sorbent)^-1 (93% of the theoretical yield). Throughout the ten cyclic processes, CO₂ sorption capacity of the sorbent had dropped approximately 16.2% from the first to the tenth cycle, which was a reasonable decline. Thus, it was concluded that Li₄SiO₄ is a potential CO₂ solid sorbent for high temperature CO₂ capture activity.

关键词: CO₂ capture, Adsorption, Carbon dioxide, Lithium orthosilicate, Sol-gel, Sorption-desorption