Synthesis, characterization and application of iron-supported activated carbon derived from Aloe vera leaves to improve anaerobic digestion of food waste: An optimization approach

Abstract

The study evaluated the effect of iron-supported activated carbon derived from Aloe vera leaves (Fe/AV-AC) as an additive for anaerobic digestion (AD) of food waste (FW). The modelling of the AD system and optimization of the process parameters were performed using response surface methodology (RSM). Cumulative biogas production (CBP), methane content (CH4%), and removal of chemical oxygen demand (COD%) of 7861.59 mL, 65.67%, and 63.65%, respectively, were obtained at optimum conditions (total solids of FW (TS%): 11.81%, Fe ratio loaded on AV-AC: 9.15 wt%, and Fe/AV-AC amount: 986.18 mg/L). The addition of Fe/AV-AC allowed higher biogas production and faster volatile fatty acids (VFAs) consumption. Biogas yield from FW-AD improved by 60.27% with Fe/AV-AC compared to without the additive, while theoretical methane increased by 44.33%. From the results, Fe/AV-AC improved AD and RSM is a suitable approach to optimize the AD of FW.