Enhanced Cyclic Stability and CO2 Capture Performance of MgO-Al2O3 Sorbent Decorated with Eutectic Mixture

Abstract

Recently, alkali nitrate activated MgO has been proposed as an alternative solid sorbent for high temperature CO2 capture due to the facile solvation of MgO in the activation step. However, it tends to be unstable under multi-cyclic sorption-regeneration process due to continuous deformation. In this work, it is demonstrated that MgO-Al2O3 composite sorbent decorated with eutectic mixture (KNO3-LiNO3) can be a feasible candidate for high temperature CO2 capture without losing cyclic performance. It is noteworthy that the eutectic mixture could activate both MgO and MgO-Al2O3 composite, while NaNO3 can only activate MgO. Also, the inactive MgO-Al2O3 is activated at high temperature sorption with the help of the eutectic mixture. Further, it is demonstrated that the EM-MgO-Al2O3 could overcome aggregation and shows stable CO2 sorption performance for 10 cycles corresponding to ∼8.7 wt.%.