As shown in Fig. 2a, the RHA800 exhibited an aggregation of numerous
nanoparticles and Fig. 2b showed that the calcined eggshell was
well distributed on the RHA800.
The EDS curves of the RHA and 30% RHA800-800 catalyst were also
acquired and several typical points on the surface of samples were selected
in order to determine the elemental contents of Ca, Si and O.
The results were shown in Table 1. It was observed that on the surface
of the RHA (Fig. 2a), the primary elements were Si and O, while on the
surface of the 30% RHA800-800 catalyst (Fig. 2b), the Ca content of the
three points (A, B and C) ranged from 20.7% to 27.4%. Apart from Ca
and Si, several metals namely potassium (K), aluminum (Al) and phosphorus
(P) were observed as the major components of the solids. They
were mostly present in the form of oxides due to the high oxygen
content.