Bimetallic and nitrogen co-doped biochar for peroxymonosulfate (PMS) activation to degrade emerging contaminants

In this study, the bimetallic and nitrogen co-doped biochar was prepared for peroxymonosulfate (PMS) activation to degrade emerging contaminants. Compared to single metal-doped biochar, bimetallic-doped biochar showed much higher catalytic activity. Iron and cobalt co-doped biochar (FeCo-BC) exhibited higher catalytic activity than iron and copper co-doped biochar (FeCu-BC). When FeCo-BC was used for PMS activation, sulfamethoxazole (SMX) could be completely removed within 10 min, with the degradation rate of 0.749 min−1, which was 2.3 and 69.4 times higher than that of Fe-BC (0.333 min−1) and Co-BC (0.0108 min−1), respectively, demonstraing the synergistic effect of bimetallic co-doping. Meanwhile, the SMX mineralization efficiency reached 57.1 %. In the system of FeCo-BC/PMS, multi reactive species produced, in which hydroxyl radicals, sulfate radicals and high-valent metal-oxo mainly contributed to SMX degradation. The superior catalytic activity of FeCo-BC was attributed to the configuration of FeNx-CoNx. In five consecutive experiments, FeCo-BC showed good catalytic activity and stability. This study provides a way to the rational design of high efficient and stable PMS catalyst, which could be used in Fenton-like reaction to remove the emerging organic contaminants.