Development of a new type of phosphoric acid based geopolymer/activated carbon composite for selective CO2 capture

Herein, a phosphoric acid based geopolymer/activated carbon (PAG/AC) composite adsorbent was prepared for selective CO2/N-2 capture. The adsorbents exhibited hierarchical pore structures with ultra-micropores (approximately 0.58 nm) and mesopores (approximately 3.83 nm). The composite with 30 wt% of AC showed a much higher CO2 adsorption capacity (17.6 cm(3)/g) than that of phosphoric acid-based geopolymer (6.8 cm(3)/g). Additionally, it had a high CO2/N-2 IAST selectivity of 12.7, which was greater than that of phosphoric acid-based geopolymer (3.9) and activated carbon (9.5). Spectral results confirmed that this was attributed to the AC ultra-micropores effect and the large interaction between phosphoric acid and AC during geo-polymerization.

Automated summary

A phosphoric acid based geopolymer/activated carbon (PAG/AC) composite adsorbent was prepared for selective CO2/N-2 capture. The composite showed hierarchical pore structures and demonstrated higher CO2 adsorption capacity and selectivity compared to phosphoric acid-based geopolymer and activated carbon, primarily due to the AC ultra-micropores effect and the interaction between phosphoric acid and AC during geo-polymerization.