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标题：Adsorption of perfluorooctanoic acid from water by pH-modulated Brönsted acid and base sites in mesoporous hafnium oxide ceramics
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作者：Fatima A. Hussain ; Samuel E. Janisse ; Marie C. Heffern 等
期刊名称：iScience
印刷版ISSN：2589-0042
出版年度：2022
卷号：25
期号：4
页码：1-17
DOI：10.1016/j.isci.2022.104138
语种：English
出版社：Elsevier
摘要：SummaryPer- and polyfluoroalkyl substances (PFAS) are increasingly appearing in drinking water sources globally. Our work focuses specifically on the adsorption of the legacy perfluorooctanoic acid (PFOA) using mesoporous hafnium oxide (MHO) ceramic synthesized via a sol-gel process. Experiments were performed at varying pH to determine the effect of surface charge on adsorption capacity of PFOA by MHO, and to postulate adsorption behavior. At pH 2.3, the adsorption capacity of PFOA on MHO was 20.9 mg/g, whereas at a higher pH of 6.3, it was much lower at 9.2 mg/g. This was due to increased coulombic attractions at lower pH between the positively charged conjugate acid active sites on MHO surface and negatively charged deprotonated PFOA anion in solution. After adsorption, the solid MHO was regenerated via calcination, reducing the amount of toxic solid waste to be disposed since the adsorbent is regenerated, and the PFOA is completely removed.Graphical abstractDisplay OmittedHighlights•The adsorption capacity of PFOA by MHO was determined to be 20.9 mg/g at pH 2.3•As pH increased, the adsorption capacity of MHO decreased due to Coulombic repulsions•MHO could be regenerated via calcination to limit the amount of toxic waste producedEnvironmental Chemistry; Chemical Engineering; Materials science; Materials chemistry