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Wyszukujesz frazę "Cerium" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Arsenate removal on the ion exchanger modified with cerium(III) ions
Autorzy:
Dudek, Sebastian
Kołodyńska, Dorota
Powiązania:
https://bibliotekanauki.pl/articles/2146888.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
arsenic
adsorption
cerium
iron oxides
Ferrix A33E
Opis:
The iron oxide ion exchanger Ferrix A33E was successfully modified with cerium(III) ions to obtain Ferrix A33E-Ce(III) providing much better sorption properties in relation to the As(V) species. The new material has been characterized using a number of techniques including scanning electron microscopy SEM, nitrogen adsorption/desorption isotherms, Fourier transform infrared spectroscopy FTIR and X-ray photoelectron spectroscopy XPS. At optimal pH 6 the main mechanism of arsenate adsorption on A33E-Ce(III) was electrostatic attraction and formation of monodentate and bidentate surface complexes. The process was exothermic and spontaneous. Unlike the unmodified ion exchanger, A33E-Ce(III) could completely remove arsenic from the arsenate solution at a concentration of 50 mg/dm3 in 60 minutes. Furthermore, the maximum sorption capacity for As(V) was determined to be 60.41 mg/g which almost doubled after modification with cerium(III) ions. It is also worth noting that even after three cycles of sorption/desorption A33E-Ce(III) exhibited a higher sorption capacity than unmodified A33E before the arsenate adsorption. It can be concluded that modifying the sorbent with a small amount of cerium(III) ions boosts its sorption properties significantly, improves effectiveness of water purification and reduces the overall operation cost
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 2 (Special issue - selected papers conference: Physicochemistry of interfaces - instrumental methods); art. no. 147412
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of alkali processing for the recycling of rare earth values from spent fluorescent lamps
Autorzy:
Shukla, Neha
Tanvar, Himanshu
Dhawan, Nikhil
Powiązania:
https://bibliotekanauki.pl/articles/1449193.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fluorescent lamps
rare earth elements
activation energy
recovery
cerium
terbium
Opis:
Phosphor samples collected after crushing and sieving of discarded fluorescent lamps comprise approximately 31 % rare earth elements in the form of $Y_{1.90}Eu_{0.10}O_3$, $Al11Ce_{0.67}MgO_{19}Tb_{0.33}$, and $Al_{10.09}Ba_{0.96}Mg_{0.91}O_{17}$: $Eu^{2+}$ phase. Direct leaching and mechanical activation assisted leaching are incapable of recovering $Ce$, $Tb$ values from the $Al_{11}Ce_{0.67}MgO_{19}Tb_{0.33}$ phase. Heat treatment with $NaOH$ was found successful for dissociation of $Ce$, $Tb$ phase via substitution of rare-earth ion by $Na^+$ ion to form rare earth oxide and water-soluble $NaAlO_2$. $Y$, $Eu$, $Ce$, and $Tb$ values were recovered from heattreated mass in a two-step leaching process followed by recovery from the leach solution by oxalic acid precipitation. Over 95 % extraction rate was attained after heat treatment at 400 °C with 150 wt-% $NaOH$ for 1 h. It was found that $Y$, $Eu$ containing phase does not take part in the heat treatment process whereas the $Ce$, $Tb$ phase undergoes a solid-state chemical reaction with $NaOH$ via product layer diffusion model with 41.5 kJ/mol activation energy. Approximately 15 g mixed oxide (purity >95 %) of $Y$ (79 %), $Eu$ (7 %), $Ce$ (5 %), and $Tb$ (4 %) could be recovered from 100 units of discarded FLs. Microwave treatment of phosphor and $NaOH$ (50 wt-%) yielded approximately 42 % $Y$, 100 % $Eu$, 65 % $Ce$, and 70 % Tb recovery in just 5 min. Approximately 9 g of REO and 5 g of cerium enriched leach residue were recovered from the microwave route within 5 min and depicted high microwave potential application in the recovery of $Ce$ and $Tb$ values from waste phosphor sample.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 4; 710-722
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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