摘要
采用微波等离子化学气相沉积技术,以铌片作为基底,制备了6种不同硼掺杂量的掺硼金刚石(Nb/BDD)电极,探究了不同硼掺杂量对Nb/BDD电极电化学性能及氧化全氟辛酸(PFOA)的影响,并将其应用于不同全氟及多氟烷基类化合物(PFASs)的电化学去除.结果表明,随着硼掺杂量的增加,Nb/BDD薄膜的晶粒尺寸逐渐减小,电极表面的电子转移速率逐渐增加,但薄膜质量下降,导致其脱落率增加.以Na_(2)SO_(4)作为电解质,在30 mA/cm^(2)电流密度下,以Nb/BDD电极为阳极在120 min内使PFOA的降解率达到78.3%,矿化率在240 min内达到78.1%.在6种不同硼掺杂量的Nb/BDD电极中,中低掺杂的Nb/BDD电极对PFOA具有更高的降解和矿化能力,说明通过调控BDD的硼掺杂量可实现PFAS的高效电化学去除.对降解产物进行分析的结果表明,PFOA的电化学降解遵循碳链逐级去除的规律,其中,阳极与污染物之间的直接电子转移是降解的关键起始步骤.通过对不同链长全氟磺酸(PFSA)和全氟羧酸(PFCA)的电化学降解发现,碳链长度与PFAS的降解率和矿化率呈正比,因此,降解产生的短链产物是限制PFAS彻底矿化的主要原因.未来需要更加关注短链和超短链PFAS的高效去除,以满足通过电化学技术实现PFAS完全无害化处理的需求.
In this study,six boron-doped diamond(Nb/BDD)electrodes with different boron doping levels were prepared using niobium flakes as the substrate by microwave plasma chemical vapor deposition,and the effects of different boron doping levels on the electrochemical performance of Nb/BDD electrodes and their oxidation of perfluorooctanoic acid(PFOA)were investigated and applied to the electrochemical removal of different perfluorosul⁃fonic acids(PFASs).The results showed that with the increase of boron doping level,the grain size of the Nb/BDD film gradually decreased and the electron transfer rate on the electrode surface gradually increased,but the decrease of film quality leads to the increase of its exfoliation rate.Na_(2)SO_(4) was used as the electrolyte,and the Nb/BDD electrode as the anode was able to oxidize PFOA within 120 min at a current density of 30 mA/cm^(2).PFOA degradation rate to 78.3%and mineralization rate to 78.1%within 240 min.Among the six Nb/BDD electrodes prepared with different boron doping levels,the medium and low-doped Nb/BDD electrodes have higher degradation and mineralization ability for PFOA,indicating that the efficient electrochemical removal of PFAS can be achieved by regulating the boron doping level of BDD.The analysis of the degradation products indicated that the electrochemical degradation of PFOA follows the law of carbon chain step-by-step removal,in which the direct electron transfer between the anode and the pollutant is the key initiation step of degradation.The electrochemical degradation of PFSA and perfluorocarboxylic acid(PFCA)with different chain lengths reveals that the length of the carbon chain is positively proportional with the degradation rate and mineralization rate of PFAS,and thus the short-chain products generated by the degradation are the main reason for limiting the complete mineralization of PFAS.In the future,more attention needs to be paid to the efficient removal of short-chain and ultrashort-chain PFAS in order to meet the demand for the complete detoxification of PFAS through electrochemical technologies.
作者
张森崇
吕继涛
王森
吕继磊
王少龙
王亚韡
ZHANG Senchong;LYU Jitao;WANG Sen;LYU Jilei;WANG Shaolong;WANG Yawei(College of Urban and Environmental Sciences,Northwest University,Xi’an 710127,China;State Key Laboratory of Environmental Chemistry and Ecotoxicology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Hubei Carbon Six Technology Co.Ltd.,Yichang 443000,China;Tubular Goods Research Institute of China National Petroleum Corporation,Xi’an 710072,China;School of Environment,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China)
出处
《高等学校化学学报》
北大核心
2025年第8期84-94,共11页
Chemical Journal of Chinese Universities
基金
中国科学院战略性先导科技专项B类(批准号:XDB0750000)
国科大杭州高等研究院专项资金(批准号:2024HIAS-P001)资助.
关键词
全氟化合物
掺硼金刚石电极
电化学氧化
新污染物
Perfluorooctanoic compound
Boron-doped diamond electrode
Electrochemical oxidation
New pollution
作者简介
联系人:王森,女,博士,副教授,主要从事新污染物的分析方法、界面迁移和转化过程、生物代谢吸收和毒性效应等方面的研究.E-mail:wangsen@nwu.edu.cn。
