Selenium and nitrogen co-doped biochar as a new metal-free catalyst for adsorption of phenol and activation of peroxymonosulfate: Elucidating the enhanced catalytic performance and stability

• Published in: Journal of hazardous materials Vol. 413; p. 125294
• Main Authors: Zhang, Kejing, Min, Xiaoye, Zhang, Tingzheng, Xie, Mingbo, Si, Mengying, Chai, Liyuan, Shi, Yan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.07.2021
• Subjects: Advanced oxidation process; Biochar; Electron transfer; Nitrogen; Selenium; Electron transfer; Selenium; Biochar; Nitrogen; Advanced oxidation process
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.125294

Coupling of adsorption and advanced oxidation processes triggered by metal-free carbocatalysts is an appealing wastewater purification scheme. However, its practical application is challenging due to the unsatisfactory stability of conventional heteroatom-doped systems. Herein, we innovatively developed a simple and scalable biochemical strategy to synthesize selenium and nitrogen co-doped biochar (Se/N-BC) as a bifunctional catalyst of adsorption-oxidation. The Se/N-BC displays the highest efficiency of phenol (PE) degradation (99.2% of PE was removed within 5 min) with the lowest dosage of catalyst (0.1 g L−1) and peroxymonosulfate (PMS, 0.4 g L−1). More importantly, the Se/N-BC is not only universal in a wide pH range of 3.0–11.0 and complex ionic environment, but also possesses an excellent cycling stability. The Se/N co-doping induces a rapid cycle of adsorption-degradation for PE. The Se/N-BC acts as an "electron transfer bridge", guiding rapid electron transfer from PE to PMS to achieve high-efficient degradation. The Se/N co-doping facilitates the formation of graphitic N and unlocks the potential of adjacent C sites for PMS activation, consequently boost oxidation efficiency. In addition, the oxidation of catalyst is prevented due to the antioxidant properties of Se, which has been a primary concern either to regenerate adsorbate or to enhance degradation performance. [Display omitted] •Se/N-BC was fabricated using the bacterial cells contained bio-reduced Se0.•The Se/N co-doping triggered a rapid cycle of adsorption-degradation for PE.•Se/N-BC activated the peroxymonosulfate through a nonradical mechanism.•The activated Se/N-BC-PMS* complex dominated the degradation reaction.•The Se-C-N sites were identified as the primary catalytic sites.