The novel SiO2-decorated highly robust waste-derived activated carbon with homogeneous fluidity for the CO2 capture process

Abstract

Biomass-derived activated carbon (AC) is considered auspicious for alleviating various environmental pollutants. We reported the usage of a developed biomass-based AC as a potential adsorbent for CO2 uptake applications to overcome global warming. In this paper, AC was successfully synthesized from a highly-used fruit in the middle east, date seeds, and chemically activated by KOH to boost CO2 uptake activity. The fluidization behavior was tested and improved through a dry-mixing route with fluidizable nanopowder. To assess the impact of utilizing the chemical activator and easily-fluidizable compound, CO2 capture efficiency and fluidity of the raw and promoted adsorbent were evaluated and compared with commercial and other date-derived ACs. The original and modified ACs were characterized via SEM, EDS, BET, FTIR, and TG analysis; the KOH-promoted AC possessed a more fluffy-like configuration and a higher surface area of about 595.94 m2/g. Based on the TG analyses, 94% and 67% higher average CO2 capture capacity was recorded for KOH-promoted ACs compared to the original and commercial adsorbents. The KOH-promoted ACs and SiO2-covered counterparts fluidization's performance was assessed under 15 vol% CO2 balanced with N2 gas. Fluidization experiments proved the positive effect of employing hydrophobic silica nanoparticles (NPs) to develop the fluidity of the synthesized activated carbon. After mixing with 2.5 wt% SiO2 NPs, the SiO2-decorated modified ACs presented a 45% higher bed expansion ratio associated with a homogeneous and bubbleless fluidized regime.