valeric acid concentration, there was a higher adsorption of
amphiphilic molecules onto particles, the hydrophobicity of
particles to adsorb to air–water interfaces was enhanced,
resulting in stable wet foams and an increasing foaming
capacity up to 2.93. Accordingly, the bulk density of porous
ceramics decreased almost linearly from 4.16 g/cm3 to 1.80 g/
cm3 in the range of valeric acid concentration, indicating that
the density could be easily tailored in a broad range.