Superheated steam for regeneration of biomass-derived activated carbon: comparative evaluation of performance, life cycle impacts and net CO2 offset potential.

Coconut-shell derived activated carbon (AC); GCN has been used extensively in water treatment as an efficient adsorbent material. However, ACs progressively saturate with contaminants over time and require periodic regeneration to regain adsorption efficiency. This study presents an advanced superheated steam (SPH) (at 600 °C) method to regenerate saturated AC. This steam drives adsorbed contaminants to break down and detach from the carbon pores. With a regeneration efficiency of 95 %, SPH regeneration outperforms conventional chemical regeneration methods. The study also involves a comprehensive life cycle assessment comparing different regeneration routes where SPH regeneration produced 10 % and 31 % less global warming emission compared to thermal and chemical regeneration respectively. Moreover, the magnitude of CO2 mitigation increased over subsequent cycles with SPH regeneration emissions reduced to half when compared to chemical regeneration at end of 5th cycle. Collectively, the study demonstrates that SPH regeneration provides both high adsorption performance and lower environmental burdens.