Coupled Kinetics of Ferrihydrite Transformation and As(V) Sequestration under the Effect of Humic Acids: A Mechanistic and Quantitative Study
Abstract
In natural environments, kinetics of As(V) sequestration/release is usually coupled with dynamic Fe mineral transformation, which is further influenced by the presence of natural organic matter (NOM). Previous work mainly focused on the interactions between As(V) and Fe minerals. However, there is a lack of both mechanistic and quantitative understanding on the coupled kinetic processes in the As(V)–Fe mineral–NOM system. In this study, we investigated the effect of humic acids (HA) on the coupled kinetics of ferrihydrite transformation into hematite/goethite and sequestration of As(V) on Fe minerals. Time-resolved As(V) and HA interactions with Fe minerals during the kinetic processes were studied using aberration-corrected scanning transmission electron microscopy, chemical extractions, stirred-flow kinetic experiments, and X-ray absorption spectroscopy. Based on the experimental results, we developed a mechanistic kinetics model for As(V) fate during Fe mineral transformation. Our results demonstrated that the rates of As(V) speciation changes within Fe minerals were coupled with ferrihydrite transformation rates, and the overall reactions were slowed down by the presence of HA that sorbed on Fe minerals. In conclusion, our kinetics model is able to account for variations of Fe mineral compositions, solution chemistry, and As(V) speciation, which has significant environmental implications for predicting As(V) behavior inmore »
- Authors:
-
- South China Univ. of Technology, Guangdong (People's Republic of China)
- Univ. of Wyoming, Laramie, WY (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Stanford Univ., Menlo Park, CA (United States)
- Publication Date:
- Research Org.:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1490874
- Grant/Contract Number:
- AC02-76SF00515; 41573090; 2016ZT06N569
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Environmental Science and Technology
- Additional Journal Information:
- Journal Volume: 52; Journal Issue: 20; Journal ID: ISSN 0013-936X
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES
Citation Formats
Hu, Shiwen, Lu, Yang, Peng, Lanfang, Wang, Pei, Zhu, Mengqiang, Dohnalkova, Alice C., Chen, Hong, Lin, Zhang, Dang, Zhi, and Shi, Zhenqing. Coupled Kinetics of Ferrihydrite Transformation and As(V) Sequestration under the Effect of Humic Acids: A Mechanistic and Quantitative Study. United States: N. p., 2018.
Web. doi:10.1021/acs.est.8b03492.
Hu, Shiwen, Lu, Yang, Peng, Lanfang, Wang, Pei, Zhu, Mengqiang, Dohnalkova, Alice C., Chen, Hong, Lin, Zhang, Dang, Zhi, & Shi, Zhenqing. Coupled Kinetics of Ferrihydrite Transformation and As(V) Sequestration under the Effect of Humic Acids: A Mechanistic and Quantitative Study. United States. https://doi.org/10.1021/acs.est.8b03492
Hu, Shiwen, Lu, Yang, Peng, Lanfang, Wang, Pei, Zhu, Mengqiang, Dohnalkova, Alice C., Chen, Hong, Lin, Zhang, Dang, Zhi, and Shi, Zhenqing. Wed .
"Coupled Kinetics of Ferrihydrite Transformation and As(V) Sequestration under the Effect of Humic Acids: A Mechanistic and Quantitative Study". United States. https://doi.org/10.1021/acs.est.8b03492. https://www.osti.gov/servlets/purl/1490874.
@article{osti_1490874,
title = {Coupled Kinetics of Ferrihydrite Transformation and As(V) Sequestration under the Effect of Humic Acids: A Mechanistic and Quantitative Study},
author = {Hu, Shiwen and Lu, Yang and Peng, Lanfang and Wang, Pei and Zhu, Mengqiang and Dohnalkova, Alice C. and Chen, Hong and Lin, Zhang and Dang, Zhi and Shi, Zhenqing},
abstractNote = {In natural environments, kinetics of As(V) sequestration/release is usually coupled with dynamic Fe mineral transformation, which is further influenced by the presence of natural organic matter (NOM). Previous work mainly focused on the interactions between As(V) and Fe minerals. However, there is a lack of both mechanistic and quantitative understanding on the coupled kinetic processes in the As(V)–Fe mineral–NOM system. In this study, we investigated the effect of humic acids (HA) on the coupled kinetics of ferrihydrite transformation into hematite/goethite and sequestration of As(V) on Fe minerals. Time-resolved As(V) and HA interactions with Fe minerals during the kinetic processes were studied using aberration-corrected scanning transmission electron microscopy, chemical extractions, stirred-flow kinetic experiments, and X-ray absorption spectroscopy. Based on the experimental results, we developed a mechanistic kinetics model for As(V) fate during Fe mineral transformation. Our results demonstrated that the rates of As(V) speciation changes within Fe minerals were coupled with ferrihydrite transformation rates, and the overall reactions were slowed down by the presence of HA that sorbed on Fe minerals. In conclusion, our kinetics model is able to account for variations of Fe mineral compositions, solution chemistry, and As(V) speciation, which has significant environmental implications for predicting As(V) behavior in the environment.},
doi = {10.1021/acs.est.8b03492},
journal = {Environmental Science and Technology},
number = 20,
volume = 52,
place = {United States},
year = {2018},
month = {9}
}
Web of Science
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