An Immobilized Amine with Improved Cyclic Performance Prepared from Carboxyl Modified Mesoporous Silica for CO2 Capture

Abstract

AbstractImmobilized amines adsorbents have excellent CO2 adsorption capacity and low regeneration energy consumption, which have broad application prospect, but poor reusability. To improve the cyclic adsorption performance of immobolized amines for CO2 capture, the mesoporous silica A‐MSU‐J with carboxyl groups on the surface was synthesized, and immobilized amine A‐MSU‐J‐TEPA was prepared by introducing tetraethylenepentamine (TEPA) by impregnation method. The introduction of carboxyl groups onto the carrier surface can form stronger hydrogen bonds with TEPA than the initial hydroxyl groups, thus achieving stable loading of TEPA. When the TEPA load was 50 wt %, the adsorption capacity of 4A‐65MSU‐J‐50TEPA declined by only 13.7 % (from 2.58 to 2.23 mmol ⋅ g−1, at 70 °C, 0.1 Mpa) after 10 cycles, while the adsorption capacity of 65MSU‐J‐50TEPA decreased by 23.6 % (from 2 to 1.53 mmol ⋅ g−1). Furthermore, carrier pore size also affects the adsorption capacity of immobilized amines for CO2. The adsorption capacity of 4A‐65MSU‐J‐50TEPA with larger pore size (2.95 mmol ⋅ g−1, at 55 °C) is much higher than that of 4A‐25MSU‐J‐50TEPA with smaller pore size (2.17 mmol ⋅ g−1). In conclusion, improving the interaction between organic amines and the carrier surface and using carriers with larger pore size can enhance the adsorption capacity and reusability of immobolized amines adsorbents.