Carbonized polyaniline activated peroxymonosulfate (PMS) for phenol degradation: Role of PMS adsorption and singlet oxygen generation

N-doped carbonaceous materials are promising efficient catalysts for peroxymonosulfate (PMS) activation. In this study, the high-efficient N-doped carbon materials were prepared by direct carbonization of polyaniline (PANI) at 700 degrees C-1000 degrees C. It was optimized that the CPANI-9 (carbonized polyaniline prepared at 900 degrees C) exhibited excellent catalytic performance to activate PMS for phenol degradation, which was efficient over a wide pH range (pH 3.5 similar to 9). In the CPANI-9/PMS system, the PMS adsorption/activation was identified as the key step determining the reaction rate. The quenching experiments and electron paramagnetic resonance demonstrated that the non-radical pathway was dominant in phenol degradation and singlet oxygen (O-1(2)) was the main active specie. Graphitic N, pyridinic N, defects and ketonic groups (C=O) were identified as catalytic sites. Interestingly, only the presence of PO43- greatly decreased the phenol degradation rate and PMS decomposition. The CPANI-9/PMS system could also degrade effectively various organic pollutants, indicating that it had potential practical application.

Automated summary

This study prepared high-efficient N-doped carbon materials by directly carbonizing polyaniline, which exhibited excellent catalytic performance in activating PMS for phenol degradation. In the CPANI-9/PMS system, PMS adsorption/activation was identified as the key step determining the reaction rate. The presence of different N species and functional groups on the carbon materials were found to be catalytic sites for the degradation reactions.