skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effects of Radiation and Temperature on Iodide Sorption by Surfactant-Modified Bentonite

Abstract

Bentonite, which is used as an engineered barrier in geological repositories, is ineffective for sorbing anionic radionuclides because of its negatively charged surface. This study modified raw bentonite using a cationic surfactant (i.e., hexadecyltrimethylammonium [HDTMA]-Br) to improve its sorption capability for radioactive iodide. The effects of temperature and radiation on the iodide sorption of surfactant-modified bentonite (SMB) were evaluated under alkaline pH condition similar to that found in repository environments. Different amounts of surfactant, equivalent to the 50, 100, and 200% cation-exchange capacity of the bentonite, were used to produce the HDTMA-SMB for iodide sorption. The sorption reaction of the SMB with iodide reached equilibrium rapidly within 10 min regardless of temperature and radiation conditions. The rate of iodide sorption increased as the amount of the added surfactant was increased and nonlinear sorption behavior was exhibited. However, high temperature and γ-irradiation (60Co) resulted in significantly (~2–10 times) lower iodide Kd values for the SMB. The results of Fourier transform infrared spectroscopy analysis suggested that the decrease in iodide sorption may be caused by weakened physical electrostatic force between the HDTMA and iodide, and by the surfactant becoming detached from the SMB during the heating and irradiation processes.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1170456
Report Number(s):
PNNL-SA-105973
600301020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science & Technology, 48(16):9684−9691
Country of Publication:
United States
Language:
English
Subject:
bentonite; surfactant; radioactive Co; repository; radiation

Citation Formats

Choung, Sungwook, Kim, Min Kyung, Yang, Jungseok, Kim, Min-Gyu, and Um, Wooyong. Effects of Radiation and Temperature on Iodide Sorption by Surfactant-Modified Bentonite. United States: N. p., 2014. Web. doi:10.1021/es501661z.
Choung, Sungwook, Kim, Min Kyung, Yang, Jungseok, Kim, Min-Gyu, & Um, Wooyong. Effects of Radiation and Temperature on Iodide Sorption by Surfactant-Modified Bentonite. United States. doi:10.1021/es501661z.
Choung, Sungwook, Kim, Min Kyung, Yang, Jungseok, Kim, Min-Gyu, and Um, Wooyong. Mon . "Effects of Radiation and Temperature on Iodide Sorption by Surfactant-Modified Bentonite". United States. doi:10.1021/es501661z.
@article{osti_1170456,
title = {Effects of Radiation and Temperature on Iodide Sorption by Surfactant-Modified Bentonite},
author = {Choung, Sungwook and Kim, Min Kyung and Yang, Jungseok and Kim, Min-Gyu and Um, Wooyong},
abstractNote = {Bentonite, which is used as an engineered barrier in geological repositories, is ineffective for sorbing anionic radionuclides because of its negatively charged surface. This study modified raw bentonite using a cationic surfactant (i.e., hexadecyltrimethylammonium [HDTMA]-Br) to improve its sorption capability for radioactive iodide. The effects of temperature and radiation on the iodide sorption of surfactant-modified bentonite (SMB) were evaluated under alkaline pH condition similar to that found in repository environments. Different amounts of surfactant, equivalent to the 50, 100, and 200% cation-exchange capacity of the bentonite, were used to produce the HDTMA-SMB for iodide sorption. The sorption reaction of the SMB with iodide reached equilibrium rapidly within 10 min regardless of temperature and radiation conditions. The rate of iodide sorption increased as the amount of the added surfactant was increased and nonlinear sorption behavior was exhibited. However, high temperature and γ-irradiation (60Co) resulted in significantly (~2–10 times) lower iodide Kd values for the SMB. The results of Fourier transform infrared spectroscopy analysis suggested that the decrease in iodide sorption may be caused by weakened physical electrostatic force between the HDTMA and iodide, and by the surfactant becoming detached from the SMB during the heating and irradiation processes.},
doi = {10.1021/es501661z},
journal = {Environmental Science & Technology, 48(16):9684−9691},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 04 00:00:00 EDT 2014},
month = {Mon Aug 04 00:00:00 EDT 2014}
}