The multiple sorptive sites on illitic clays (e.g., frayed edge [FES], type II [TS], and planar sites [PS]) are related to variable 137Cs immobilization in subsurface environments. This study investigated the diverse Cs+ sorption using 10 illitic clays under various competing K+ (distilled water−10−1 mol L−1) and Cs+ concentrations (10−7−10−3 mol L−1). In addition, the multisite cation exchange model was simulated the best-fit sorption models compared to experimental datasets, and subsequently, optimized the sorption capacities of multiple sorptive sites on the illitic clays. The best-fit sorption model exhibited that diverse Cs+ sorption of 10 illitic clays was closely linked to the individual sorption capacities at the FES (1.76 × 10−5 to 1.12 × 10−4 eq kg−1), TS (1.59 × 10−3 to 9.76 × 10−3 eq kg−1), and PS (2.14 × 10−2 to 1.51 × 10−1 eq kg−1). The FES predominantly sorbed Cs+ at low aqueous-phase concentrations, whereas the TS and PS contributed to Cs+ sorption at relatively high concentrations. These sorption capabilities were correlated to illite contents and crystallinity of 10 illitic clays so that such parameters could be significant factors to predict the Cs+ sorption for illitic clays. Finally, the 1-D transport simulations showed significantly diverse Cs+ retardation (Rd ≈ 20–100) at low dissolved Cs+, implying that the various FES capacities of illitic clays could play an important role on Cs+ distribution in actual radioactive contamination sites.
|Journal||Journal of Hazardous Materials|
|Publication status||Published - 2023 Jan 5|
Bibliographical noteFunding Information:
This research was supported by the Subsurface Environmental Management (SEM) project through the Korea Environmental Industry and Technology Institute (KEITI), funded by the Ministry of Environment (Grant Number: 2018002440003 ); by the Nuclear Research and Development project through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT ( NRF-2021M2E1A1085187 ). The analytical and experimental works of this study were supported by Korea Basic Science Institute ( C230120, C280100 ) and NRF ( NRF-2019R1A2C1004891 ). The authors also thank PhreeqcUsers Forum ( https://phreeqcusers.org ) for comments that helped set up and calculate the cation exchange model.
© 2022 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Health, Toxicology and Mutagenesis