Coconut shell biochar (CSB) based catalyst samples were prepared via concentrated sulfuric acid. The
biochar were sulfonated according to the method of Toda et al. [2005]. 100 mL of concentrated sulfuric
acid was added to 5 g of biochar in a 500 mL round bottom flask. The mixture was heated to 150o
C for 12
hours. After heating, the slurry was placed in cool distilled water and filtered. The biochar catalyst was
washed with 80o
C distilled water until the wash water was neutral and free from sulfate ions. Then, the
biochar was dried in an oven at 70o
C for approximately 1 h. BET surface area, average pore diameter and
total pore volume of the catalysts were determined by nitrogen adsorption–desorption isotherm at 77.35 K
using the BET method. FT-IR spectra of various samples were employed to identify the functional groups
in the catalysts. The total acid site density was measured via back titration method. The elements
composition were analyzed by XRF.