Wei Ren, Gang Nie, Peng Zhou, Hui Zhang*, Xiaoguang Duan*, Shaobin Wang
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引用次数: 383
Abstract
Persulfates activation by carbon nanotubes (CNT) has been evidenced as nonradical systems for oxidation of organic pollutants. Peroxymonosulfate (PMS) and peroxydisulfate (PDS) possess discrepant atomic structures and redox potentials, while the nature of their distinct behaviors in carbocatalytic activation has not been investigated. Herein, we illustrated that the roles of nitrogen species in CNT-based persulfate systems are intrinsically different. In PMS activation mediated by nitrogen-doped CNT (N-CNT), surface chemical modification (N-doping) can profoundly promote the adsorption quantity of PMS, consequently elevate potential of derived nonradical N-CNT–PMS* complexes, and boost organic oxidation efficiency via an electron-transfer regime. In contrast, PDS adsorption was not enhanced upon incorporating N into CNT due to the limited equilibrium adsorption quantity of PDS, leading to a relatively lower oxidative potential of PDS/N-CNT system and a mediocre degradation rate. However, with equivalent persulfate adsorption on N-CNT at a low quantity, PDS/N-CNT exhibited a stronger oxidizing capacity than PMS/N-CNT because of the intrinsic higher redox potential of PDS than PMS. The oxidation rates of the two systems were in great linearity with the potentials of carbon–persulfate* complexes, suggesting N-CNT activation of PMS and PDS shared the similar electron-transfer oxidation mechanism. Therefore, this study provides new insights into the intrinsic roles of heteroatom doping in nanocarbons for persulfates activation and unveils the principles for a rational design of reaction-oriented carbocatalysts for persulfate-based advanced oxidation processes.
过硫酸盐被碳纳米管(CNT)活化已被证明是有机污染物氧化的非自由基系统。过氧单硫酸盐(PMS)和过氧二硫酸盐(PDS)具有不同的原子结构和氧化还原电位,而它们在碳催化活化中的不同行为的性质尚未被研究。在此,我们说明了氮种在碳纳米管基过硫酸盐系统中的作用本质上是不同的。在氮掺杂碳纳米管(N-CNT)介导的PMS活化中,表面化学修饰(n-掺杂)可以显著提高PMS的吸附量,从而提高衍生的非自由基N-CNT - PMS*配合物的电位,并通过电子转移机制提高有机氧化效率。相比之下,由于PDS的平衡吸附量有限,PDS/N-CNT体系的氧化电位相对较低,降解率一般,因此加入N后PDS的吸附并没有增强。然而,当过硫酸盐在n -碳纳米管上的吸附量较低时,PDS/ n -碳纳米管表现出比PMS/ n -碳纳米管更强的氧化能力,这是因为PDS比PMS具有更高的氧化还原电位。两种体系的氧化速率与过硫酸碳*络合物电位呈线性关系,表明N-CNT活化PMS和PDS具有相似的电子转移氧化机制。因此,本研究为杂原子掺杂纳米碳在过硫酸盐活化中的内在作用提供了新的见解,并揭示了合理设计反应导向碳催化剂用于过硫酸盐高级氧化工艺的原则。
期刊介绍:
Environmental Science & Technology (ES&T) is a co-sponsored academic and technical magazine by the Hubei Provincial Environmental Protection Bureau and the Hubei Provincial Academy of Environmental Sciences.
Environmental Science & Technology (ES&T) holds the status of Chinese core journals, scientific papers source journals of China, Chinese Science Citation Database source journals, and Chinese Academic Journal Comprehensive Evaluation Database source journals. This publication focuses on the academic field of environmental protection, featuring articles related to environmental protection and technical advancements.