Thermocatalytic degradation of industrial waste lignin to prepare activated carbon

Abstract

Activated carbons were prepared from industrial waste lignin by thermocatalytic degradation using various activating agents. The degradation was carried out in presence of chemical activating reagents such as ZnCl2, K2CO3, Na2CO3, KOH and NaOH. All the degradations were carried out at the temperature 500°C and the impregnation ratio of lignin and activating reagent was maintained as 1:1. The maximum yield of activated carbon was obtained with ZnCl2 activation which is 58% of the lignin charged. The proximate and elemental analysis of all the activated carbons showed high carbon content of activated carbon as compared to lignin. The comparative study of FTIR showed almost flattening of maximum peaks in activated carbon. The SEM analysis reveals that the lignin particles has been softened, melted and diffused into the mass of matrix with number of pores on its surface after thermal degradation. The maximum BET surface area 819.82 m2/g was achieved by the activated carbon prepared by ZnCl2 activation which is comparable to commercially available activated carbon. ZnCl2 works as effective dehydration reagent and restricted the formation of tar and promoted the charring and aromatization of carbon upto carbonization temperature 500°C.