The enhanced peroxydisulfate activation performance of nitrogen doped biochar encapsulating cobalt in three-dimensional electrochemical system for sulfadiazine removal and mechanism

Abstract

To boost the peroxydisulfate (PDS) activation performance of biochar (BC) encapsulating cobalt (Co@RBC) in the three-dimensional (3D) electrochemical system, serials N-doped BC encapsulating cobalt (Co@RBC-xN) was prepared using urea as N sourcing and rose petals as biomaterials in this work. Results revealed that N doping can largely promote the PDS activation performance of Co@RBC toward sulfadiazine (SD) degradation in the 3D electrochemical system. The structure-activity relationship analysis revealed that Co0 and sp2-C/sp3-C in catalysts promoted by the doped pyridinic N benefited in strengthening PDS utilization on catalysts surface, thus largely boosting PDS activation efficiency for SD degradation in the system even with a low PDS dosage (0.5 mM). And pyridine N and Co0 were main active sites for PDS activation. Integrating with reactive species trapping experiments and electron paramagnetic resonance (EPR), it revealed that singlet oxygen (1O2), superoxide radical (•O2−) and surface-bounded radicals made main contribution to SD degradation. In addition, the as-prepared Co@RBC-3 N exhibited excellent and stable catalytic activity, good anti-interference of natural water matrices, and easily magnetic separation from solution. This study developed an effective, stable and easily recovery catalysts for PDS activation in 3D electrochemical system and promoted the application possibility of this system for antibiotics removal from wastewater.