The adsorption of U(VI) on chlorite: batch, modeling and XPS study

IF 1.4 3区 化学 Q4 CHEMISTRY, INORGANIC & NUCLEAR
Qiang Jin, Yuxiong Wang, Xin Zhao, Ye Fan, Xinya Diao, Zongyuan Chen, Zhijun Guo
{"title":"The adsorption of U(VI) on chlorite: batch, modeling and XPS study","authors":"Qiang Jin, Yuxiong Wang, Xin Zhao, Ye Fan, Xinya Diao, Zongyuan Chen, Zhijun Guo","doi":"10.1515/ract-2024-0278","DOIUrl":null,"url":null,"abstract":"A mechanistic modelling of the adsorption processes onto individual minerals presenting in the near- and far-fields can greatly enhance the credibility of long-term safety assessments of granite-based geological repositories. In this study, the titration and U(VI) adsorption characteristics of chlorite, one of the major minerals of rock fractures, have been studied. Potentiometric titration curves at two ionic strengths (0.1 and 0.4 mol/L NaCl) are successfully interpreted by considering protonation/deprotonation reactions on generic edge sites (≡SOH) in the framework of a non-electrostatic surface complexation model (SCM). The adsorption of U(VI) on chlorite was reached after 24 h, the adsorption kinetics can be described by a pseudo-second-order model. A non-electrostatic SCM with three surface complexes (≡SOUO<jats:sub>2</jats:sub> <jats:sup>+</jats:sup>, ≡SO(UO<jats:sub>2</jats:sub>)<jats:sub>3</jats:sub>(OH)<jats:sub>5</jats:sub> and ≡SO(UO<jats:sub>2</jats:sub>)<jats:sub>3</jats:sub>(OH)<jats:sub>7</jats:sub> <jats:sup>2−</jats:sup>) was set up based on pH edges of U(VI) at adsorption equilibrium in the absence of CO<jats:sub>2</jats:sub>. Additional, experimental data measured as a function of U(VI) concentration, solid-to-liquid ratio and carbonate concentration were well reproduced by the proposed model. Finally, parallel experiments were conducted using X-ray photoelectron spectroscopy (XPS) to analyze the variation of U(VI) surface species speciation at different pH values. The good agreement between SCM prediction and XPS analysis demonstrates the reliability of the model in predicting and quantifying the radionuclides retention by chlorite.","PeriodicalId":21167,"journal":{"name":"Radiochimica Acta","volume":"22 1","pages":""},"PeriodicalIF":1.4000,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Radiochimica Acta","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1515/ract-2024-0278","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0

Abstract

A mechanistic modelling of the adsorption processes onto individual minerals presenting in the near- and far-fields can greatly enhance the credibility of long-term safety assessments of granite-based geological repositories. In this study, the titration and U(VI) adsorption characteristics of chlorite, one of the major minerals of rock fractures, have been studied. Potentiometric titration curves at two ionic strengths (0.1 and 0.4 mol/L NaCl) are successfully interpreted by considering protonation/deprotonation reactions on generic edge sites (≡SOH) in the framework of a non-electrostatic surface complexation model (SCM). The adsorption of U(VI) on chlorite was reached after 24 h, the adsorption kinetics can be described by a pseudo-second-order model. A non-electrostatic SCM with three surface complexes (≡SOUO2 +, ≡SO(UO2)3(OH)5 and ≡SO(UO2)3(OH)7 2−) was set up based on pH edges of U(VI) at adsorption equilibrium in the absence of CO2. Additional, experimental data measured as a function of U(VI) concentration, solid-to-liquid ratio and carbonate concentration were well reproduced by the proposed model. Finally, parallel experiments were conducted using X-ray photoelectron spectroscopy (XPS) to analyze the variation of U(VI) surface species speciation at different pH values. The good agreement between SCM prediction and XPS analysis demonstrates the reliability of the model in predicting and quantifying the radionuclides retention by chlorite.
U(VI)在绿泥石上的吸附:批处理、建模和 XPS 研究
对个别矿物在近场和远场的吸附过程进行机理建模,可以大大提高对以花岗岩为基础的地质处置库进行长期安全评估的可信度。本研究对岩石裂缝的主要矿物之一绿泥石的滴定和 U(VI)吸附特性进行了研究。通过在非静电表面络合模型(SCM)框架内考虑一般边缘位点(≡SOH)上的质子化/去质子化反应,成功解释了两种离子强度(0.1 和 0.4 摩尔/升 NaCl)下的电位滴定曲线。24 小时后,U(VI) 在绿泥石上达到吸附,其吸附动力学可以用伪二阶模型来描述。在没有二氧化碳的情况下,根据吸附平衡时 U(VI)的 pH 值边缘,建立了具有三种表面络合物(≡SOUO2 +、≡SO(UO2)3(OH)5 和≡SO(UO2)3(OH)7 2-)的非静电 SCM。此外,根据 U(VI)浓度、固液比和碳酸盐浓度的函数测量的实验数据也很好地再现了所提出的模型。最后,还利用 X 射线光电子能谱(XPS)进行了平行实验,分析了不同 pH 值下 U(VI)表面物种标示的变化。单片机预测与 XPS 分析之间的良好一致性证明了该模型在预测和量化绿泥石对放射性核素的保留方面的可靠性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Radiochimica Acta
Radiochimica Acta 化学-核科学技术
CiteScore
2.90
自引率
16.70%
发文量
78
审稿时长
6 months
期刊介绍: Radiochimica Acta publishes manuscripts encompassing chemical aspects of nuclear science and technology.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信