Thermal stabilization effect and oxygen replacement reaction together regulate N/S co-doped microporous carbon synthesis

Abstract

AbstractPotassium thiocyanate (KSCN) activation showed great potential to prepare N/S co-doped microporous carbon for environmental remediation, however, predictable preparation for targeted application was a challenge. This study suggested that thermal stabilization effect and oxygen replacement reaction during KSCN activation could together regulate pore formation and N/S co-doping. Results showed that carbonaceous precursor with high thermal stability (expressed by high R50 index) could support stable carbon matrix for KSCN pore-forming. Meanwhile, carbonaceous precursor with high polarity (expressed by high O/C) was more prone to occur oxygen replacement reaction, promoting N/S co-doping. N/S co-doped microporous carbon with high micropore surface area can promote BPA adsorption via the pore-filling mechanism. However, reaction induced by S contained groups can enhance heavy metal (Pb2+) adsorption while prepared material with S doping. In summary, a carbonaceous precursor with high R50 index was conducive to preparing carbon material for organic pollutant adsorption, while the carbonaceous precursor with high O/C was suit to fabricate carbon material with high adsorption capacity for Pb2+ immobilization. This study provided important insights into the directional synthesis of optimized N/S doped microporous carbon. Graphical Abstract