Preparation and characterization of mesoporous activated carbons from waste watermelon rind by using the chemical activation method with zinc chloride

Waste watermelon rind was analyzed as a precursor for preparing activated carbons by using a one-step chemical activation process by zinc chloride. The effects of activation parameters, i.e., carbonization temperature, impregnation ratio, and impregnation time on the properties of the final products were tested in detail. The resultant activated carbons were characterized using elemental analysis, the Brunauer–Emmet–Teller method, pore property analysis, N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, the point of zero charge, Boehm titration method and scanning electron microscopy. The maximal Brunauer–Emmett–Teller surface area of the resultant activated carbon, produced by using the impregnation (ZnCl2/dried watermelon rind) ratio of 2/1 at the carbonization temperature of 700 °C with the residence time of 60 min, was 1156 m2/g. Upon using the impregnation ratio of 3/1 at the carbonization temperature of 600 °C with the residence time of 60 min, the maximal total pore volume, which also contains the highest mesopore volume, was 1.41 cm3/g.