Synthesis protocols similar to those reported for activated carbons derived from garlic skin were used. The biomass precursor (e.g., garlic roots) was thoroughly rinsed, washed several times with DI water, dried in the oven at 100 o C overnight and sieved to less than or equal to 350 microns particle size. The powdered samples were carbonized in a tube furnace in N2 atmosphere. About 26 g of pulverized garlic roots were heated to 600 o C at a heating rate of 5.0 o C min -1 in a 100 x 45 x 20 mm alumina crucible. The sample was kept at 600 o C for 2 hours and then cooled slowly to room temperature. The yield of carbonization was around 30-35 % for all the samples. The carbonized garlic roots sample was mixed with KOH (mass KOH : mass carbon = 4:1) and ∼30 mL DI water to form a homogeneous slurry. The slurry was transferred to a custom-made nickel sample holder and heated to 800 o C at 5.0 o C min -1 under N2 in the tube furnace. The temperature was maintained at 800 o C for 2 h before the sample was cooled to room temperature. The obtained sample was dissolved in 100 mL DI water and washed with 1 M HCl (20-30 mL) around 3-4 times to remove the remaining impurities (K, K2O, KOH, and K2CO3). It was further washed with DI water until the pH reached 7. The resulting sample was dried in the oven at 120 o C overnight to obtain activated carbon powder. The final yield from garlic roots and garlic powder varied between 10-15 % while no significant yield was obtained from garlic skin. For garlic skin, the carbonization and activation time were therefore reduced to 1 h and activation temperature was reduced to 700 o C to obtain around 11 % yield from garlic skin. The activated carbon samples obtained from garlic roots, garlic powder, and garlic skin were named as GR-AC, GP-AC, and GS-AC, respectively. The remaining carbons were named as BPL-AC, S-AC, and Y-AC, respectively.