Preparation and characterization of activated carbon from a low rank coal Original Research Article

Powdered activated carbon has been prepared from lignitic coal of Lakhra (Pakistan) by a chemical activation method using ZnCl2 as an activating agent. Different process variables have been established after a series of experiments and an impregnation ratio of 1:2, an activation temperature of 650 °C and a duration of 1 hour have been found to be appropriate for its preparation. It has been found that the char is obtained in high yield with iodine and methylene blue numbers of 990 and 205, respectively. Different parameters based on adsorption of benzene at 293 K under reduced pressure have been calculated using DR equation with micropore volume W0 = 0.46 cm3/g, an average pore width L = 0.98 nm and a microporous surface area Smi = 942 m2/g. The nonporous surface area Se calculated by the tF method is 142 m2/g. FTIR spectra of this sample show the presence of acidic functional carboxylic groups developed on its surface after activation. Their predominance is further confirmed by neutralization with different alkalis.