Conclusions
We have successfully prepared meshed hollow sphere CaO- based absorbents using carbon colloid
spheres as templates. By means of urea homogenous hydrolysis precipitation of Ca2 þ ions to the
colloidal carbon spheres templates, a cage-like spheres structure formed after calcination, which
consists of twisted strips with mesopores. The obtained absorbent has a good stability and high
capacity. The absorbent has a nearly 75% initial absorption capacity and an above 94% CaO
conversion at an absorption temperature of 600 1C with 50 vol% CO2 for 45 min. After 28
absorption/desorption cycles performed at 700 1C calcinations with N2 for 20 min, the capacity
uptake still maintains 63%, showing a considerable stability. By the comparison of CaO- based
meshed hollow spheres with the two other reference sorbent samples during the same
absorption/desorption process, its excellent performance especially, its cyclic absorption
capacity, could be attributed to meshed hollow sphere structure facilitating the formation of
uniform, disperse, and loose CaO particles after multi-cycles. The template of carbon spheres plays
a crucial role in