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Leaching of immobilized cesium from NaOH-activated fly ash-based geopolymers
https://orcid.org/0000-0001-9909-1640
Abstract This study investigated the effects of cesium (Cs) dosage (2–20 wt.%) and curing time (7–180 days) on the leaching behavior and immobilization of Cs in NaOH-activated fly ash-based geopolymers (FA-GP). The Cs leaching behavior and leachability index (LX) were evaluated per ANS-16.1. FA-GP were characterized using XRD and N2 adsorption-desorption isotherms. The results revealed that Cs dosage affects the resulting phases and pore structure of FA-GP and influences the Cs immobilization. The higher Cs dosage (≥8 wt.%) provides conditions for in-situ pollucite crystallization within the FA-GP matrix (cured at 90 °C for 7 days) and significantly enhances Cs immobilization (LX values from 11.5 to 14.5). Cs leaching resistance of FA-GP cured at 22 °C improved with curing time. Diffusion was determined to be the primary leaching mechanism. The results advocate the use of FA-GP as an effective immobilization material, mainly containing a high concentration of Cs.
Graphical abstract Display Omitted
Highlights Cesium dosage and curing time affected cesium immobilization in fly ash geopolymers. High cesium dosage (≥8 wt.%) aided formation of in-situ pollucite in geopolymers. Leaching resistance of geopolymers cured at 22 °C improved with curing time. Diffusion was determined to be the primary leaching mechanism.
Leaching of immobilized cesium from NaOH-activated fly ash-based geopolymers
https://orcid.org/0000-0001-9909-1640
Abstract This study investigated the effects of cesium (Cs) dosage (2–20 wt.%) and curing time (7–180 days) on the leaching behavior and immobilization of Cs in NaOH-activated fly ash-based geopolymers (FA-GP). The Cs leaching behavior and leachability index (LX) were evaluated per ANS-16.1. FA-GP were characterized using XRD and N2 adsorption-desorption isotherms. The results revealed that Cs dosage affects the resulting phases and pore structure of FA-GP and influences the Cs immobilization. The higher Cs dosage (≥8 wt.%) provides conditions for in-situ pollucite crystallization within the FA-GP matrix (cured at 90 °C for 7 days) and significantly enhances Cs immobilization (LX values from 11.5 to 14.5). Cs leaching resistance of FA-GP cured at 22 °C improved with curing time. Diffusion was determined to be the primary leaching mechanism. The results advocate the use of FA-GP as an effective immobilization material, mainly containing a high concentration of Cs.
Graphical abstract Display Omitted
Highlights Cesium dosage and curing time affected cesium immobilization in fly ash geopolymers. High cesium dosage (≥8 wt.%) aided formation of in-situ pollucite in geopolymers. Leaching resistance of geopolymers cured at 22 °C improved with curing time. Diffusion was determined to be the primary leaching mechanism.
Leaching of immobilized cesium from NaOH-activated fly ash-based geopolymers
https://orcid.org/0000-0001-9909-1640
Abstract This study investigated the effects of cesium (Cs) dosage (2–20 wt.%) and curing time (7–180 days) on the leaching behavior and immobilization of Cs in NaOH-activated fly ash-based geopolymers (FA-GP). The Cs leaching behavior and leachability index (LX) were evaluated per ANS-16.1. FA-GP were characterized using XRD and N2 adsorption-desorption isotherms. The results revealed that Cs dosage affects the resulting phases and pore structure of FA-GP and influences the Cs immobilization. The higher Cs dosage (≥8 wt.%) provides conditions for in-situ pollucite crystallization within the FA-GP matrix (cured at 90 °C for 7 days) and significantly enhances Cs immobilization (LX values from 11.5 to 14.5). Cs leaching resistance of FA-GP cured at 22 °C improved with curing time. Diffusion was determined to be the primary leaching mechanism. The results advocate the use of FA-GP as an effective immobilization material, mainly containing a high concentration of Cs.
Graphical abstract Display Omitted
Highlights Cesium dosage and curing time affected cesium immobilization in fly ash geopolymers. High cesium dosage (≥8 wt.%) aided formation of in-situ pollucite in geopolymers. Leaching resistance of geopolymers cured at 22 °C improved with curing time. Diffusion was determined to be the primary leaching mechanism.
Leaching of immobilized cesium from NaOH-activated fly ash-based geopolymers
Jain, Shubham (author) / Banthia, Nemkumar (author) / Troczynski, Tom (author)
2022-07-11
Article (Journal)
Electronic Resource
English
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