Effective enhancement of CO2 capture performance of solid amine adsorbents prepared from diethylenetriamine-modified mesoporous silica: optimisation experiments and kinetic calculations

In this study, four DETA-SiO2 solid amine adsorbents were prepared by an impregnation method using diethylenetriamine (DETA) as the amine source and four types of silica with different pore structures as the carrier, and the effects of varying amine concentrations, temperatures and pressures on the CO2 adsorption performance were investigated. The results showed that the prepared N-MCM-48-C material reached a maximum CO2 adsorption of 417.45 mg g−1 at 25°C and 0.5 MPa. The effect of pressure on the adsorption performance was verified by kinetic calculations using the intraparticle diffusion model and the Thomas dynamic adsorption model. The presence of surfactant (CTAB) inside the carrier diluted the amine concentration, which improved the homogenisation of the amine on the carrier and increased the CO2 mass transfer efficiency and adsorption capacity. Multiple pressure swing adsorption (PSA) experiments have shown that N-MCM-48-C material has stable adsorption performance during the PSA process and the adsorption capacity can reach 300 mg g−1.