Efficient CF4 adsorption on porous carbon derived from polyaniline

Abstract

BackgroundAs a significant greenhouse gas emitted in large quantities from the electrolytic aluminum and semiconductor industries, tetrafluoromethane (CF4) has an extremely high global warming potential (GWP) and a fairly long atmospheric lifetime. MethodsIn this study, porous carbon was prepared via a thermochemical process involving the carbonization and K2CO3 activation of precursor polyaniline (PANI). The activation temperature (600–800 ℃) and K2CO3/carbonized PANI mass ratio (1–4) had significant influences on the porous structure and CF4 uptake of the PANI-derived porous carbon (PDC). Significant findingsThe prepared PDC-3-800 adsorbent exhibited the largest specific surface area (2268 m2 g−1) and highest pore volume (1.48 cm3 g−1), whereas PDC-2-700 adsorbent demonstrated the highest CF4 uptake of up to 2.16 mmol g−1 at 25 ℃ and 1 bar. Notably, CF4 uptake was predominantly dependent on the presence of narrow micropores with diameters below 0.9 nm at atmospheric pressure. The CF4 adsorption isotherms were well fitted by the dual-site Langmuir (DSL) model. Moreover, the isosteric heat of adsorption and CF4/N2 selectivity of PDCs were investigated. These experimental results demonstrate that PDCs with high CF4 adsorption capacity, excellent CF4/N2 selectivity, and good recyclability, have immense potential for practical CF4 capture applications.