12 Producing Fuels and Fine Chemicals from Biomass Using Nanomaterials
was a mixture of Al, Fe, Si, Ca, and Mg oxides. Ethylene was used as carbon source
for the CNT growth through a CVD process. CNFs grown on the red soil were found
to exhibit a broad diameter distribution. The quality of the CNFs was comparable to
that produced using lava rock as catalyst/support [20].
Endo and his group used garnet sand pulverized from natural garnet stones (Ube
Sand Kogyo, 1.4 USD/kg) as a catalyst and cheap urban household gas ($1.1 m
−3
) as
a carbon source for the CVD process [23]. After CVD, the 200-mm-sized granulates
of garnet powder (Figure 2.3a) were coarsened to about 400 mm (Figure 2.3b) and
were covered with CNTs (Figure 2.3c and d). About 25%