Production and characterization of lignocellulosic biomass-derived activated carbon

摘要

The goal of this work is to establish the technical feasibility of producing activated carbonnfrom pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials,ntwo sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigatednexperimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activationntemperature (400–6008C) and activation time (1 to 2 h) on the development of porosity.nThe activation products were characterized for their physical and chemical properties usingna surface area analyzer, scanning electron microscopy and Fourier transform infrarednspectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosicnbiomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organicnmolecules. The results show that the activated carbon are highly porous with specific surfacenarea greater than 500m2/g. The yield of activated carbon was greater than the percent ofnfixed carbon in the dry sludge, suggesting that the activation process was able to capture ansubstantial amount of carbon from the organic matter in the sludge. While 4008C was too low,n6008C was high enough to sustain a substantial rate of activation for linerboard sludge.nThe KOH/biomass ratio, activation temperature and time all play important roles in porendevelopment and yield control, allowing optimization of the activation process. MB adsorptionnfollowed a Langmuir isotherm for all four activated carbon, although the adsorption capacitynof NK-primary sludge-derived activated carbon was considerably lower than the rest,nconsistent with its lower specific surface area.