X-ray diffraction analyses of the materials were carried out using
a Philips Diffractometer model PW1710 with Cu Ka radiation
and crystal monochrome graphite with a wavelength of
l1 ¼ 1.5406 Å. Fig. 1 shows the X-ray diffraction patterns of the
materials used in this study. SCBA was observed to have characteristic
quartz diffraction peaks, indicating that a part of the residue
has a crystalline structure.