the fresh CCAN-
80 looks more fluffy and porous compared to CaO, and after
25 or 50 cycles, its micro-morphology is well maintained though
the grain size slightly increases. As distinct contrast, the morphology
of the CaO sorbent after multiple cycles is greatly modified,
showing much larger grain size and smoother surface with few
small pores, a clear indication of heavy sintering of CaO particles