However, the appearance of the second peak seems to be the only visible difference between the FT-IR spectra of BC0 and the rest of the BC samples. The appearance of peaks in this region commonly indicates the presence of a double bond. Although pure BC does not contain any C=O or C=C groups, SSGO contains a definite carboxylic group (Khan & Park, 2008). Accordingly, this peak might appear due to entrapment of certain molecules of SSGO in the BC.