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- Title
Thorium(IV) removal and recovery from aqueous solutions using modified silica nanoparticles with cysteine or methionine amino acids.
- Authors
Ismail, Latifa S.; Khalili, Fawwaz I.; Abu Orabi, Faten M.
- Abstract
In this study, SiO2 nanoparticles were modified by cysteine (SiO2-Cys) or methionine (SiO2- Meth) and then applied for removal thorium(IV) ion from aqueous solution. Silica nanoparticles and its modified forms were characterized by elemental analysis, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray fluorescence, thermogravimetric analysis, differential scanning calorimetry, Brunauer-Emmett-Teller, zeta potential, and Fourier transform infrared analyses. Sorption of Th(IV) ion using a batch technique by silica nanoparticles, SiO2-Cys and SiO2-Meth was studied as a function of pH, sorbent dosage, temperature, initial concentration, and contact time. The kinetic studies show that sorption of Th(IV) ion by silica nanoparticles, SiO2-Cys, and SiO2-Meth was well-described by the pseudo-second-order equation. Negative values of Gibbs free energy (ΔG°) suggest the spontaneity of the sorption process on silica nanoparticles and its modified forms (SiO2-Cys) and (SiO2-Meth). Positive values of enthalpy (ΔH°) indicate the endothermic adsorption process. The sorption isotherm was better fitted by Langmuir model with maximum sorption capacity for silica nanoparticles, SiO2-Cys and SiO2-Meth was found to be 5.3, 8.2, and 7.0 mg/g at 25°C, respectively. Desorption studies indicate that the most favorable desorption reagent for Th(VI) is 0.1 M nitric acid.
- Subjects
SILICA nanoparticles; AMINO acids; AQUEOUS solutions; THORIUM; CYSTEINE; X-ray fluorescence; METHIONINE
- Publication
Desalination & Water Treatment, 2020, Vol 196, p161
- ISSN
1944-3994
- Publication type
Article
- DOI
10.5004/dwt.2020.25936