Performance, life cycle assessment, and economic comparison between date palm waste biochar and activated carbon derived from woody biomass

Abstract

Currently, comparisons between biochar and activated carbon in terms of performance, environmental impacts as well as financial implications are limited. In this study, biochar sourced from date palm waste were analysed using gate-to-grave life cycle assessment approach and results were compared to activated carbon derived from woody biomass. Simapro 8.5 software was used to quantitatively simulate the environmental impacts of both adsorbents. Date palm waste biochar and activated carbon global warming potentials (GWPs) were found to be 1.53 and 8.96 kg CO_2eq/kg respectively. The cumulative energy demand (CED) for producing date palm waste biochar was found to be 20.3 MJ/kg, whereas, activated carbon resulted in 119.5 MJ/kg. Both adsorbents' performance in terms of adsorption capacity were compared, and it was found that biochar is comparable with activated carbon. The economic performance demonstrated that the average cost of production of date palm waste biochar and activated carbon were $1.06/kg and $1.34/kg, respectively. Sensitivity analysis showed that when the source of energy was changed to renewable energy, a CED dropped to 105.2 MJ/kg and 7.68 MJ/kg, a GWP dropped to 7.29 kg CO₂ eq. and 0.665 kg CO₂ eq. and production costs dropped to $1.30 and to $1.04 for producing activated carbon and biochar respectively. Based on the results of the study, date palm waste biochar is more cost-effective, shows less environmental impact, and has comparable adsorption efficiency as compared to activated carbon.

Keywords: Adsorption capacity; Cost efficiency; Disposal; Environmental impact; Sensitivity analysis.