A novel method to convert Cs-polluted soil into pollucite-base glass-ceramics for Cs immobilization

Wang, Tianhe; Zhang, Zhengyi; Ke, Zhenkun; Shan, Chuanli; Cao, Xin; Ma, Lifeng; Peng, Shou

doi:10.1016/j.cej.2019.123844

Cited by 33 publications

(4 citation statements)

References 37 publications

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“…Chen et al [124] proposed a hybrid hydrothermal-sintering pro- Thermal treatment has been proposed as an effective method to further improve the S/S efficiency of Cs (Figure 3). Under high temperatures, geopolymer can be viewed as precursor for the formation of ceramic, and meanwhile, pollucite has been regarded as one of the most stable phases for the safe disposal of Cs [120]. It has been reported that geopolymer containing Cs + could be gradually crystallized into pollucite upon heating above 900 • C [121].…”

Section: Csmentioning

confidence: 99%

Application of Geopolymer in Stabilization/Solidification of Hazardous Pollutants: A Review

et al. 2022

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Geopolymers, as a kind of inorganic polymer, possess excellent properties and have been broadly studied for the stabilization/solidification (S/S) of hazardous pollutants. Even though many reviews about geopolymers have been published, the summary of geopolymer-based S/S for various contaminants has not been well conducted. Therefore, the S/S of hazardous pollutants using geopolymers are comprehensively summarized in this review. Geopolymer-based S/S of typical cations, including Pb, Zn, Cd, Cs, Cu, Sr, Ni, etc., were involved and elucidated. The S/S mechanisms for cationic heavy metals were concluded, mainly including physical encapsulation, sorption, precipitation, and bonding with a silicate structure. In addition, compared to cationic ions, geopolymers have a poor immobilization ability on anions due to the repulsive effect between them, presenting a high leaching percentage. However, some anions, such as Se or As oxyanions, have been proved to exist in geopolymers through electrostatic interaction, which provides a direction to enhance the geopolymer-based S/S for anions. Besides, few reports about geopolymer-based S/S of organic pollutants have been published. Furthermore, the adsorbents of geopolymer-based composites designed and studied for the removal of hazardous pollutants from aqueous conditions are also briefly discussed. On the whole, this review will offer insights into geopolymer-based S/S technology. Furthermore, the challenges to geopolymer-based S/S technology outlined in this work are expected to be of direct relevance to the focus of future research.

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Section: Csmentioning

confidence: 99%

Application of Geopolymer in Stabilization/Solidification of Hazardous Pollutants: A Review

et al. 2022

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“…Due to the high content of Cs (up to 47% Cs by weight), it has been considered as a candidate host matrix for the immobilization of radioactive Cs. Pollucite glass–ceramics have been prepared from geopolymer containing Cs + by high‐temperature treatment or hydrothermal method, 1,5–7 and so on 8–11 . The simple synthesis process provides a new route for nuclear waste disposal.…”

Section: Introductionmentioning

confidence: 99%

“…Pollucite glass-ceramics have been prepared from geopolymer containing Cs + by high-temperature treatment or hydrothermal method, 1,[5][6][7] and so on. [8][9][10][11] The simple synthesis process provides a new route for nuclear waste disposal. Interactions between nuclear waste glass-ceramics and the aqueous environment are responsible for releasing radionuclides from the disposal facility.…”

Section: Introductionmentioning

confidence: 99%

Insights into the leaching behavior of pollucite glass–ceramics at the initial stage

Yang

Zhao

et al. 2022

J Am Ceram Soc.

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Pollucite has been proposed as an ideal candidate material for addressing the critical challenge of the safe trapping of the 137Cs radionuclide. However, its detailed corrosion mechanism remains elusive. In this work, we performed reactive and ab initio molecular simulations to explore the leaching behavior of Cs+ from pollucite glass–ceramics at the initial stage. The nonbridging oxygen ions on the surface are protonated at first, followed by the release of Cs+ associated with these oxygen ions. For the glass phase, the inner Cs+ could leach out due to the interaction with water molecules, whereas only the Cs+ present at the surface leach out for pollucite, confirming its remarkable chemical stability. The hydrolysis of Si/Al–O bonds in pollucite is thermodynamically unfavorable, and Al–O bonds are the weak spots. Moreover, the migration barriers of Cs+ in pollucite were calculated by the climbing image nudged elastic band method, and the high barriers reveal that pollucite immobilizes Cs+ stably. This study paves the way for predicting the long‐term safety of a nuclear waste immobilization repository.

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“…In the zeolite structure of pollucite, Cs + ions can be trapped without leakage into the environment, thereby leading to more robust immobilization than that achieved using cement solidification. Previous studies have reported the synthesis of pollucite from incineration ash via hydrothermal synthesis methods. − With the addition of stable Cs 2 CO 3 and CsCl, Cs was immobilized in a composite product that included pollucite from alkali-activated pyrophyllite and Cs-contaminated municipal solid waste incineration fly ash . This indicates that pollucite can also be prepared from woody biomass gasification ashes.…”

Section: Introductionmentioning

confidence: 99%

Cesium-Catalyzed Hydrogen Production by the Gasification of Woody Biomass for Forest Decontamination

et al. 2021

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The large quantities of contaminated wood produced following the radioactive cesium decontamination of forests after the Fukushima Daiichi Nuclear Power Plant accident in 2011 can be used as a biomass resource for energy production via thermal treatment (e.g., gasification). To store the radioactive Cs ash produced from gasification, the immobilization of Cs in the pollucite structure is possible and requires stable Cs additives. In this study, a Cs additive (Cs 2 CO 3 , CsCl, CsNO 3 , or Cs 2 SO 4 ) was doped with timber waste sawdust (1−30 wt %). Fixed-bed downdraft-type continuous steam gasification experiments (0.7 g/min) showed that Cs 2 CO 3 enhanced H 2 production by 157% at 800 °C. X-ray absorption fine structure analysis and scanning electron microscopy observations revealed that the form of Cs on the surface of the char was Cs 2 CO 3 , which provided the active sites for gasification acceleration. Thermogravimetric pyrolysis and CO 2 gasification experiments showed that Cs 2 CO 3 lowered the activation energy and frequency factor while also enhancing the reactivity.

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A novel method to convert Cs-polluted soil into pollucite-base glass-ceramics for Cs immobilization

Cited by 33 publications

References 37 publications

Application of Geopolymer in Stabilization/Solidification of Hazardous Pollutants: A Review

Application of Geopolymer in Stabilization/Solidification of Hazardous Pollutants: A Review

Insights into the leaching behavior of pollucite glass–ceramics at the initial stage

Cesium-Catalyzed Hydrogen Production by the Gasification of Woody Biomass for Forest Decontamination

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