Taguchi-based process optimization for activation of agro-food waste biochar and performance test for dye adsorption

The optimization of process parameters for biochar activation is crucial for enhancing its surface area and adsorptive potentials. This work attempts to investigate the influence of activating agent (e.g., steam and KOH), temperature (700-900 degrees C) and activation time (60-120 min) using Taguchi L-18 (2(1) x 3(2)) experimental design for the activation of biochar derived from food waste and agricultural crop residues such as canola hull and oat hull. Among all the factors, activating agent and temperature influenced surface area considerably. KOH-assisted chemical activation of biochar at 800 degrees C for 90 min was found to be optimal with higher specific surface areas of 1760, 1718 and 1334 m(2)/g for food waste, canola hull and oat hull derived biochar, respectively. Finally, the comparative evaluation of the performances of biochar and activated carbon samples was achieved through the adsorption of common dyes such as methylene blue, methyl violet and rhodamine B. Activated carbon samples derived from food waste biochar and canola hull biochar exhibited a complete removal of methylene blue and methyl violet from model aqueous solution within 1-2 h of contact time at room temper-ature, whereas in case of rhodamine B only 91-94% removal was achieved.

Automated summary

The optimization of process parameters for biochar activation is crucial for enhancing its surface area and adsorptive potentials. KOH-assisted chemical activation of biochar at 800 degrees C for 90 min was found to be optimal with higher specific surface areas. The performances of biochar and activated carbon samples were evaluated through the adsorption of common dyes, showing promising results for activated biochar derived from food waste and agricultural crop residues.