Preparation and characterization of porous carbon material from post-extracted algal residue by a thermogravimetric system

Post-extracted algal residue (AR), a processing by-product from a Chlorella production enterprise, was evaluated as a novel feedstock for preparing porous carbon material. Using a thermogravimetric system at the heating rate of 10 °C/min in this work, a combined carbonization-activation process using nitrogen-carbon dioxide (N2-CO2) gases was used to prepare the carbon products at the activation temperature of 900 °C and different holding times from 0 to 60 min. The pore properties of the resulting activated products were investigated by means of nitrogen adsorption-desorption isotherms and scanning electron microscopy (SEM). Based on the pore properties, activation temperature at around 900 °C with longer holding time seemed to be preferred for the production of highly microporous carbon material, where its optimal BET surface area and t-plot micropore area were around 800 and 640 m2/g, respectively. This micropore characterization was also shown in the analyses of nitrogen isotherms and pore size distribution. More consistently, the pore volume of the resulting activated products increased with holding time ranging from 0 to 60 min. On the other hand, we clearly observed the porous structures of the resulting carbon products by SEM as compared to its precursor (i.e., AR).