Efficient Removal of Polyvalent Metal Ions (Eu(III) and Th(IV)) from Aqueous Solutions by Polyurea-Crosslinked Alginate Aerogels

Georgiou, Efthalia; Pashalidis, Ioannis; Raptopoulos, Grigorios; Paraskevopoulou, Patrina

doi:10.3390/gels8080478

Cited by 15 publications

(14 citation statements)

References 36 publications

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“…The groundwater was sampled from a local well; the wastewater, which corresponds to the effluent of secondary treatment, was obtained from a municipal wastewater treatment plant; and the seawater sample was collected from a coastal area of the island. The pH and main components of the environmental waters, which have been analyzed as described elsewhere [ 10 , 11 ], are summarized in Table 1 .…”

Section: Methodsmentioning

confidence: 99%

“…A wide spectrum of physical, chemical, and biological processes has been developed and applied for the removal of radionuclides from the nuclear process and contaminated wastewaters including membrane and osmosis technologies, sorption and ion exchange, chemical precipitation, electroremediation, and bioremediation [ 8 ]. Adsorption technologies are of particular interest since effective adsorbents such as metal organic frameworks [ 9 ], aerogels [ 10 , 11 , 12 ], silica-based materials [ 13 ], polymers [ 14 , 15 ], biomasses [ 16 , 17 , 18 , 19 ], and carbon-based composites [ 20 , 21 , 22 , 23 , 24 , 25 ] can be prepared easily and at low-cost. One such material is biochar, prepared by the pyrolysis of residual dry biomass and agricultural waste.…”

Section: Introductionmentioning

confidence: 99%

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Removal of 241Am from Aqueous Solutions by Adsorption on Sponge Gourd Biochar

2023

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Luffa cylindrica biomass was converted to biochar and the removal of 241Am by pristine and oxidized biochar fibers was investigated in laboratory and environmental water samples. This species has the added advantage of a unique microsponge structure that is beneficial for the production of porous adsorbents. The main purpose of this study was to valorize this biomass to produce an efficient adsorbent and investigate its performance in radionuclide-contaminated waters. Following the preparation of Am3+ solutions at a concentration of 10−12 mol/L, the adsorption efficiency (Kd) was determined as a function of pH, adsorbent mass, ionic strength, temperature, and type of aqueous solution by batch experiments. At the optimum adsorbent dose of 0.1 g and pH value of 4, a log10Kd value of 4.2 was achieved by the oxidized biochar sample. The effect of temperature and ionic strength indicated that adsorption is an endothermic and entropy-driven process (ΔH° = −512 kJ mol−1 and ΔS° = −1.2 J K−1 mol−1) leading to the formation of inner-sphere complexes. The adsorption kinetics were relatively slow (24 h equilibrium time) due to the slow diffusion of the radionuclide to the biochar surface and fitted well to the pseudo-first-order kinetic model. Oxidized biochar performed better compared to the unmodified sample and overall appears to be an efficient adsorbent for the treatment of 241Am-contaminated waters, even at ultra-trace concentrations.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Removal of 241Am from Aqueous Solutions by Adsorption on Sponge Gourd Biochar

2023

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“…Because of this difference, these two materials behave differently versus the sorption of heavy metal ions. X-alginate aerogels with the aromatic polyurea can efficiently uptake Pb(II) [145], U(VI) [38], Eu(III) and Th(IV) [146], while X-alginate aerogels with the aliphatic polyurea are not so efficient. For example, for Pb(II), the qmax values are equal to 20.8 g kg -1 and 6.8 g kg -1 , respectively [147].…”

Section: Uranium Sorption By Aerogelsmentioning

confidence: 99%

Uranium Removal from Aqueous Solutions by Aerogel-Based Adsorbents – A critical review

Georgiou¹,

Raptopoulos²,

Anastopoulos³

et al. 2022

Preprint

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Aerogel-based adsorbents present extraordinary sorption capacity for hexavalent uranium that can be as high as 8.8 mol kg–1 (2088 g kg–1). The adsorption data follow generally the Langmuir isotherm model and the kinetic data are better described by the pseudo-second-order kinetic model, which is associated with chemisorption. Evaluation of the thermodynamic data reveals that the adsorption is generally an endothermic, entropy-driven process (ΔHo, ΔSo > 0). Spectroscopic studies (e.g., FTIR, XPS) indicate that the adsorption is based on the formation of in-ner-sphere complexes between surface active moieties and the uranyl cation. Regeneration and uranium recovery by acidification and complexation using carbonate or chelating ligands (e.g., EDTA) have been found to be successful. The application of aerogel-based adsorbents to uranium removal from industrial processes and uranium-contaminated waste waters was also successful, assuming that these materials could be very attractive as adsorbents in water treatment and uranium recovery technologies. However, the selectivity of the studied materials towards hexavalent uranium is limited suggesting further development of aerogel materials which could be modified by surface derivatization with chelating agents (e.g., salophen, iminodiacetate) presenting high selectivity for uranyl moieties.

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“…Because of this difference, these two materials behave differently versus the sorption of heavy metal ions. X-alginate aerogels with the aromatic polyurea can efficiently uptake Pb(II) [ 145 ], U(VI) [ 39 ], Eu(III) and Th(IV) [ 146 ], while X-alginate aerogels with the aliphatic polyurea are not so efficient. For example, for Pb(II), the q max values are equal to 20.8 g kg –1 and 6.8 g kg –1 , respectively [ 147 ].…”

Section: Uranium Sorption By Aerogelsmentioning

confidence: 99%

Uranium Removal from Aqueous Solutions by Aerogel-Based Adsorbents—A Critical Review

et al. 2023

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Aerogels are a class of lightweight, nanoporous, and nanostructured materials with diverse chemical compositions and a huge potential for applications in a broad spectrum of fields. This has led the IUPAC to include them in the top ten emerging technologies in chemistry for 2022. This review provides an overview of aerogel-based adsorbents that have been used for the removal and recovery of uranium from aqueous environments, as well as an insight into the physicochemical parameters affecting the adsorption efficiency and mechanism. Uranium removal is of particular interest regarding uranium analysis and recovery, to cover the present and future uranium needs for nuclear power energy production. Among the methods used, such as ion exchange, precipitation, and solvent extraction, adsorption-based technologies are very attractive due to their easy and low-cost implementation, as well as the wide spectrum of adsorbents available. Aerogel-based adsorbents present an extraordinary sorption capacity for hexavalent uranium that can be as high as 8.8 mol kg–1 (2088 g kg–1). The adsorption data generally follow the Langmuir isotherm model, and the kinetic data are in most cases better described by the pseudo-second-order kinetic model. An evaluation of the thermodynamic data reveals that the adsorption is generally an endothermic, entropy-driven process (ΔH0, ΔS0 > 0). Spectroscopic studies (e.g., FTIR and XPS) indicate that the adsorption is based on the formation of inner-sphere complexes between surface active moieties and the uranyl cation. Regeneration and uranium recovery by acidification and complexation using carbonate or chelating ligands (e.g., EDTA) have been found to be successful. The application of aerogel-based adsorbents to uranium removal from industrial processes and uranium-contaminated waste waters was also successful, assuming that these materials could be very attractive as adsorbents in water treatment and uranium recovery technologies. However, the selectivity of the studied materials towards hexavalent uranium is limited, suggesting further developments of aerogel materials that could be modified by surface derivatization with chelating agents (e.g., salophen and iminodiacetate) presenting high selectivity for uranyl moieties.

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Efficient Removal of Polyvalent Metal Ions (Eu(III) and Th(IV)) from Aqueous Solutions by Polyurea-Crosslinked Alginate Aerogels

Cited by 15 publications

References 36 publications

Removal of 241Am from Aqueous Solutions by Adsorption on Sponge Gourd Biochar

Removal of 241Am from Aqueous Solutions by Adsorption on Sponge Gourd Biochar

Uranium Removal from Aqueous Solutions by Aerogel-Based Adsorbents – A critical review

Uranium Removal from Aqueous Solutions by Aerogel-Based Adsorbents—A Critical Review

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