Mesoporous TiO2 as the support of tetraethylenepentamine for CO2 capture from simulated flue gas

Abstract

Mesoporous TiO₂ (MT) was prepared by a hydrothermal method and used as the supporting material for the immobilization of tetraethylenepentamine (TEPA) to develop a new type of adsorbent for CO₂ capture from flue gas. The CO₂ adsorption capacity increases with the increase of the TEPA loading amounts. With the maximum TEPA loading of 31 wt% onto the MT sorbent, the maximum CO₂ adsorption capacity reached 2.52 mmol of CO₂ g⁻¹ of sorbent. In the presence of an appropriate amount of water vapor, the formation of bicarbonate and hydroxylated surface on TiO₂ can improve CO₂ adsorption capacity from 2.64 to 2.91 mmol g⁻¹. However, an excess of water vapor leads to a decrease in the CO₂ adsorption capacity from 2.91 to 2.65 mmol g⁻¹, probably attributed to the adsorption competition between water and CO₂. The absorption/regeneration cycle was repeated and the CO₂ adsorption capacity decreased from 2.52 to 2.41 mmol g⁻¹ over 5 cycles, almost completely maintained its original CO₂ adsorption capacity. In addition, the effect of long-term storage on CO₂ adsorption capacity is studied. After approximately one year of storage, the CO₂ capacity of the MT–TEPA-31 decreased by 28% compared with the fresh sample.