生物炭
吸附
催化作用
热解
金属
掺杂剂
材料科学
无机化学
活性炭
化学
化学工程
有机化学
兴奋剂
光电子学
工程类
作者
Dahu Ding,Liang Zhou,Fuxing Kang,Shengjiong Yang,Rongzhi Chen,Tianming Cai,Xiaoguang Duan,Shaobin Wang
标识
DOI:10.1021/acsami.0c15861
摘要
Biochar is a promising candidate for the adsorptive removal of organic/inorganic pollutants, yet its role in metal-free catalyzed advanced oxidation processes still remains ambiguous. In this work, five biochar samples (PPBKx, where x represents the pyrolysis temperature) were prepared by using metal-enriched phytoremediation plant residue as the feedstock. Notably, PPBK exhibited a high specific surface area (as high as 1090.7 m2 g-1) and outstanding adsorption capacity toward ciprofloxacin (CIP, as much as 1.51 ± 0.19 mmol g-1). By introducing peroxymonosulfate (PMS, 5 mM) as the chemical oxidant, over 2 mmol g-1 CIP was synergistically adsorbed and oxidized within 30 min although PMS itself could not oxidize CIP efficiently, suggesting the formation of reactive oxidative species. Theoretical calculations revealed that PMS anions preferentially adsorbed on the activated C atoms adjacent to the graphitic N dopant, where the carbon matrix served as the electron donor, instead of as an electron mediator. The adsorbed PMS possessed a smaller molecular orbital energy gap, indicating that it was much easier to be activated than free PMS anions. Surface-bound reactive species were elucidated to be the dominant contributor through chemical quenching experiments and electrochemical characterizations. The catalytic activity of PPBK700 could be greatly retained in repeated oxidations because of the stable N species, which serve as the active catalytic sites, while the CIP adsorption was greatly deteriorated because of the diminishing active adsorption sites (carbon matrix edge) caused by the partial oxidation of PMS. This work not only provides a facile and low-cost approach for the synthesis of functional biochar toward environmental remediation but also deepens the understanding of biochar-catalyzed PMS activation and nonradical oxidation.
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