HDPy 및 HDTMA로 개질된 벤토나이트에 대한 Re(VII)의 흡착반응 분석
Investigation of Sorption Reaction of Re(VII) onto HDPy- and HDTMA-modified Bentonite
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Technetium-99 (99Tc) is recognized as a critical concern in the disposal of spent nuclear fuel due toits long half-life and remarkable stability, existing predominantly as TcO4−in the natural environment. The anionicform of technetium is highly soluble and mobile, posing significant environmental risks from the viewpoint ofnuclear waste management. Thus, developing efficient and cost-effective sorbents for aqueous Tc(VII) is essentialfor mitigating relevant contamination. In the present work, the adsorption characteristics of Re(VII), a chemicalanalog of Tc(VII), were investigated using the clay mineral bentonite, modified with two different organic cations:hexadecylpyridinium (HDPy) and hexadecyltrimethylammonium (HDTMA). Sorption experiments were conductedat a liquid-to-solid ratio of 1 g/L with Re(VII) solutions prepared at concentrations from 10−4 mol/L to 10−6 mol/L. The sorption ratio and distribution coefficients were determined with samples collected at reaction times of 10,50, 100, and 500 minutes after 0.45 μm syringe filtration. In parallel, the modified bentonite samples were furtheranalyzed using the X-ray diffraction (XRD) method to understand the adsorption mechanism of Re(VII) onto thetarget minerals. According to the quantification analysis results, a rapid equilibrium reaction of aqueous Re(VII) forall modified bentonite samples was identified. Moreover, near-complete adsorption of Re(VII) was observed whenthe bentonite was modified at 200-400% of its cation exchange capacity (CEC) for both organic cations. For casesof lower modification, the HDTMA-modified bentonite showed relatively higher adsorption efficiency comparedwith the one modified with HDPy. This result was inferred to be due to the difference in inter-layer spacing basedon the characteristics of the organic cations. It is expected that the results obtained through this study will serve as apreliminary case for the synthesis of adsorbents for the retardation of highly mobile anionic radionuclides, such as Iand Tc, in the natural environment.
Abstract
Technetium-99 (99Tc) is recognized as a critical concern in the disposal of spent nuclear fuel due toits long half-life and remarkable stability, existing predominantly as TcO4−in the natural environment. The anionicform of technetium is highly soluble and mobile, posing significant environmental risks from the viewpoint ofnuclear waste management. Thus, developing efficient and cost-effective sorbents for aqueous Tc(VII) is essentialfor mitigating relevant contamination. In the present work, the adsorption characteristics of Re(VII), a chemicalanalog of Tc(VII), were investigated using the clay mineral bentonite, modified with two different organic cations:hexadecylpyridinium (HDPy) and hexadecyltrimethylammonium (HDTMA). Sorption experiments were conductedat a liquid-to-solid ratio of 1 g/L with Re(VII) solutions prepared at concentrations from 10−4 mol/L to 10−6 mol/L. The sorption ratio and distribution coefficients were determined with samples collected at reaction times of 10,50, 100, and 500 minutes after 0.45 μm syringe filtration. In parallel, the modified bentonite samples were furtheranalyzed using the X-ray diffraction (XRD) method to understand the adsorption mechanism of Re(VII) onto thetarget minerals. According to the quantification analysis results, a rapid equilibrium reaction of aqueous Re(VII) forall modified bentonite samples was identified. Moreover, near-complete adsorption of Re(VII) was observed whenthe bentonite was modified at 200-400% of its cation exchange capacity (CEC) for both organic cations. For casesof lower modification, the HDTMA-modified bentonite showed relatively higher adsorption efficiency comparedwith the one modified with HDPy. This result was inferred to be due to the difference in inter-layer spacing basedon the characteristics of the organic cations. It is expected that the results obtained through this study will serve as apreliminary case for the synthesis of adsorbents for the retardation of highly mobile anionic radionuclides, such as Iand Tc, in the natural environment.
참고문헌 (6)
- Sheng D, "Efficient and selective uptake of TcO4-by a cationic metal-organic framework material with open Ag+ sites", Environmental Science & Technology, 51(6), pp.3471~3479 (2017)[DOI]
- Nikolic AM, "Removal of 99Tc(VII)by organo-modified bentonite", Applied Clay Science, 95, pp.294~302 (2014)[DOI]
- Li Y, "Organic modification of bentonite and its application for perrhenate(an analogue of pertechnetate)removal from aqueous solution", Journal of the Taiwan Institute of Chemical Engineers, 62, pp.104~111 (2016)[DOI]
- Yang J, "Hexadecylpyridinium(HDPy)modified bentonite for efficient and selective removal of 99Tc from wastewater", Chemical Engineering Journal, 382, pp.122894~ (2020)[DOI]
- Park JA, "Bacteriophage removal in various clay minerals and clay-amended soils", Environmental Engineering Research, 20(2), pp.133~140 (2015)[DOI]
- Ltifi I, "Physicochemical characteristics of organophilic clays prepared using two organo-modifiers : alkylammonium cation arrangement models", Applied Water Science, 8, pp.1~8 (2018)[DOI]