Mild-temperature regenerable modified activated carbon fiber felt loaded with epoxide-modified aminating agents for efficient CO2 capture from simulated indoor air

Abstract

Aminated adsorbents are efficient for CO2 capture from indoor air, but mild-temperature regeneration is challenging. In this study, the epoxide-modified pentaethylenehexamine (PEHA) was loaded in the modified activated carbon fiber felt (ACF), and the formed hydroxyl groups after the reaction of 1,2-epoxybutane (EB) with PEHA made the adsorbent stable and efficient for CO2 adsorption and desorption. The optimized adsorbent, denoted as EB-PEHA-ACF, had the CO2 adsorbed amount of 60 mg/g in the simulated indoor air with 1000 ppm CO2 and 50% relative humidity. The adsorbent exhibited fast desorption kinetics, and nearly 100% of adsorbed CO2 could be desorbed within 25 min even at 60 ℃. Especially, this spent EB-PEHA-ACF could be successfully regenerated at 50 ℃, and the adsorbent showed almost stable adsorption capacity in ten adsorption and regeneration cycles. Fourier Transform Infrared (FTIR) analysis showed that the functional group peaks of EB-PEHA-ACF were unchanged before and after the ten CO2 adsorption-desorption cycles.