(253h) Studies on the Self-Activation Mechanism of Lithium-Based Sorbent for Enhancing Its Sorption Capacity

Authors: 
Zhang, S., East China University of Science and Technology
Zhang, Q., East China University of Science and Technology
Shen, C., East China University of Science and Technology
Zhu, Z., East China University of Science and Technology
Peng, D., East China University of Science and Technology

In this work, the self-activation behaviours of the lithium-based sorbent were studied. It is found that compared with that of Li4SiO4, the capacity of K-doped Li4SiO4 sorbent was largely improved after several absorption-desorption cycles. A series of characterization methods were performed and the results showed that the pore widening occurred on the K-doped Li4SiO4 sorbent during cycling. This phenomenon that the sorption capacity increases with cycling was defined as self-activation. It was also found that the key point of this self-activation process was the existence of the eutectic compound, because during cycling, the eutectic compound enhances the CO2 diffusion and large pores were formed. The pore widening during activation process was proved to be beneficial to the sorption ability by reducing the CO2 diffusion resistance, for the capacity of 20-40 mesh activated K-doped Li4SiO4 sorbent (c.a. 5.0 mmolCO2/g sorbent) is quite similar with that of the fine powder sorbent (c.a. 5.2mmol/g). Furthermore, the activated sorbent showed superior sorption ability under critical conditions, nearly 20 times that of the untreated one at 450°C under 10vol% CO2 atmosphere. Finally, the activated K-doped Li4SiO4 sorbent present excellent cyclic performance, indicating its good application prospect.