Effect of chemical activating agents on surface area and methylene blue uptake capacity of activated carbons

Abstract

Activated carbon from Acacia asak (Fabaceae) tree branches was prepared utilizing three-steps- process and H3PO4, ZnCl2, H2SO4, K2CO3, NaOH and KOH as chemical activating agents. In addition to the elemental analysis of precursor materials, produced activated carbon (ATB-AC) was also analyzed for moisture content, ash content, pH value, bulk density, volatile matter, hardness, specific surface area (SBET), iodine number and pore volume. Results revealed that the quality of ATB-AC is well comparable to the available commercial activated carbon (CAC). The SBET was found to be in the order of ATB-AC1> ATB- AC2> ATB-AC4> ATB-AC6> ATB-AC3> ATB-AC5. All the produced ATB-AC demonstrated good MB (methylene blue) removal efficiency, whereas ATB-AC1 and ATB-AC2 (produced from H3PO4, and ZnCl2) showed higher efficiency. It is concluded that the chemical activating agent has significant effect on produced AC keeping all other production parameters constant. Among the six studied chemicals, H3PO4 and ZnCl2 produced AC exhibited high SBET surface area and MB uptake capacity.