A Review on Preparation and Characterization of Activated Bio-Char

Activated charcoal (AC) is a carbonaceous material with high surface area due to high degree of micro-porosity which makes it a very versatile adsorbent for utilization in industrial, medicinal, environmental and other fields. Ligno-cellulosic biomass (eg. pine needles, paddy stubbles, other waste agricultural residue) can be a prominent raw material for activated bio-char due to its abundance, slow decomposition (which lead to fire/ air pollution). The main factors which affect the AC characteristics (surface area, micropore volume, mesopore volume) are biomass properties, impregnation ratio, impregnation time, activation temperature and activation time. The specific surface area, micropore, mesopore decreases after optimum value with continually increase in impregnation ratio and impregnation time. The activation temperature and impregnation ratio also affect the AC yield significantly. Sorption capacity get affected by adsorbent doses, contact time, agitation speed, adsorption temperature due to availability of active binding sites, adsorptive forces/ bonds.