 Characterization  Determination  Results and remarks  References 
 Elemental analysis  C, H, O, S, and N associated ratios  H/C, O/C, and N associated ratios are used to determine the degree of aromaticity and maturation  [56, 60, 61]  BET  Surface area, pore structures, average pore diameter, pore volume, and average pores of BC  1057 m^{2}g^{−1}; macroporosity and microporosity; 5.2 nm; 0.24 mLg^{−1}; 3.3 nm  [63, 125]  Boehm titration  Acidic and basic functional groups  Functional groups determined include carboxylic, lactonic, and phenolic  [45, 65]  FTIR/FTIS  Changes that occur in BC preparations as well as chemical functional groups present on the original BC  Changes include dehydration, pyrolysis, graphene nucleation, and finally carbonization; O–H (3600–3100 cm^{−1}), C=C and C=O stretching (1740–1600 cm^{−1}), C–O–C symmetric stretching (1097 cm^{−1}), –COOMe (1400–1500 cm^{−1}), and so on  [66–68]  CEC  Measure of the surface charge in soil or BC  At aging 278 to 518 mmol_{c}kg^{−1}, 10.2 to 69.2 mmol_{c}kg^{−1}, at neutral pH and 16.2 ± 6.0 and 21.0 ± 17.2 mmol_{c}kg^{−1 }for BC produced at 400 and 600°C  [19, 69] 

