Solution combustion synthesis derived Li₄SiO₄ for post-combustion carbon capture

ABSTRACT

Lithium-based sorbents are considered as promising candidates for post-combustion carbon capture because of their superior stability compared to CaO. In the present study, Li₄SiO₄ powders were synthesized by Solution Combustion Synthesis (SCS) technique using LiNO₃ as lithium source, TEOS as silicon source and citric acid as the fuel. CO₂ sorption tests were carried out for the synthesized samples and, powder prepared at 650°C during 4 h, which has 17 µm of particle size, 5.2 m² g⁻¹ of specific surface area, 85.2% Li₄SiO₄ phase purity with 97 nm of crystallite size showed a sorption performance as 29.5 wt% CO₂ uptake value, in thermobalance test under 92 vol% CO₂ (N₂ balance) gas concentration at 600°C. The sample had a CO₂ uptake value of 21.4 wt% under 20 vol% CO₂ concentration which was chosen to simulate industrial off-gas conditions. Also, the same sample showed a good cyclic durability during the sorption/desorption tests. The sample maintained its cyclic CO₂ uptake capability range between 21 and 24 wt% for 15 cycles.

KEYWORDS:

• Solution combustion synthesis
• lithium orthosilicate
• solid sorbent
• CO₂ capture

Acknowledgement

Kagan Benzesik also acknowledges the TİNÇEL Foundation for the financial support for his research visit to Instituto de Carboquimica, Zaragoza, Spain.

Disclosure statement

No potential conflicts of interest was reported by the authors.

Statement of novelty

Li₄SiO₄ is a critical material for both CCS technologies and fusion reactors. Conventionally and commercially, Li₄SiO₄ is synthesized via solid-state synthesis. This technique requires very high energy consumption to heat up the reactant materials (Li₂CO₃ and SiO₂) resulting in synthesized powders having very large particle size and crystallite size. Combustion synthesis methods provide synthesized ceramic powders with low energy requirement and in nano-size. With this study, Li₄SiO₄ powders as solid sorbent for post-combustion carbon capture were synthesized via solution combustion technique and CO₂ uptake characteristics were fully investigated. The sorbent showed a sorption performance as 29.5 wt% CO₂ uptake value, in thermobalance test under 92 vol% CO₂ (N₂ balance) gas concentration at 600°C.

Additional information

Funding

This work is funded by the Scientific Research Projects Coordination Unit (BAP) at Istanbul Technical University [Project no: 42201].