“…Therefore, materials with phosphonic acid functionality are widely used for extraction and separation of lanthanides and actinides. [17][18][19][20][21][22][23][24][25][26][27]. There are many reports on the sorption of uranium species from aqueous phases by phosphorus-containing sorbents.…”
One-pot synthesis of highly ordered SBA-15 type silica-tethered phosphonic acid at weakly acidic pH (3.75) allows for higher loading of phosphonic functionality (up to 33%) without significant deterioration of the mesostructure. In this synthesis sodium metasilicate was used instead of tetraethylorthosilicate. The resulting samples featured high specific surface areas (362-533 m 2 /g) and well developed mesoporosity. The hexagonal structure and high concentration of phosphonic acid groups (1.0-3.0 mmol/g) in the synthesized samples were established by XRD, TEM, EDS and elemental analysis methods. Since inexpensive sodium metasilicate was used as a source of silica, these materials can be of interest for large scale applications.Experimental studies of the synthesized materials showed that they are effective for extraction of trace uranium species under weak basic conditions (pH 8.3), which are relevant for practical use such as uranium extraction from seawater.
“…Therefore, materials with phosphonic acid functionality are widely used for extraction and separation of lanthanides and actinides. [17][18][19][20][21][22][23][24][25][26][27]. There are many reports on the sorption of uranium species from aqueous phases by phosphorus-containing sorbents.…”
One-pot synthesis of highly ordered SBA-15 type silica-tethered phosphonic acid at weakly acidic pH (3.75) allows for higher loading of phosphonic functionality (up to 33%) without significant deterioration of the mesostructure. In this synthesis sodium metasilicate was used instead of tetraethylorthosilicate. The resulting samples featured high specific surface areas (362-533 m 2 /g) and well developed mesoporosity. The hexagonal structure and high concentration of phosphonic acid groups (1.0-3.0 mmol/g) in the synthesized samples were established by XRD, TEM, EDS and elemental analysis methods. Since inexpensive sodium metasilicate was used as a source of silica, these materials can be of interest for large scale applications.Experimental studies of the synthesized materials showed that they are effective for extraction of trace uranium species under weak basic conditions (pH 8.3), which are relevant for practical use such as uranium extraction from seawater.
“…It was observed that in case of the solutions containing 0.5 mol/dm 3 and 0.5 mol/dm 3 Cl − with increasing temperature the extraction initially increased from 69.6 (294 K) to 78.6 % (296 K) and then slightly decreased to value 76.3 % (319 K), but in case of the solution containing 0.5 mol/dm 3 and 3 mol/dm 3 Cl − the increasing temperature increased the extraction from 81.3 (299 K) to 98.9 % (319 K). The enthalpy of the cobalt extraction were also calculated and the results obtained from the slopes of the Van’t Hoff plots [21] indicated the endothermic nature of the extraction process from the solution containing 0.5 mol/dm 3 and 1.5 or 3 mol/dm 3 Cl − (∆ H = 17.23 and 108.14 kJ/mol, respectively), whereas the cobalt(II) extraction from solution containing 0.5 mol/dm 3 and 0.1 mol/dm 3 Cl − was exothermic process (∆ H = −41.13 kJ/mol).Fig. 6Influence of temperature on extracion of Co(II) ions with 1-(2-pyridyl)tridecan-1-one oxime dissolved in toluene with 10 % (v/v) addition of decan-1-ol {[Co 2+ ] = 0.01 mol/dm 3 ; [] = 0.5 mol/dm 3 ; [Cl − ] = 0.1, 0.5, 1.5 and 3 mol/dm 3 }…”
In present paper the equilibrium of cobalt extraction with 1-(2-pyridyl)tridecan-1-one oxime from the chloride/sulphate solutions was studied. The presented results indicated that extraction depends on a number of process variables, including the pH, metal and Cl− concentration in the aqueous feed, and concentration of the oxime in the organic phase. The created cobalt-complexes with the 2-pyridine ketoxime were stable and only concentrated HCl was found to be a suitable stripping agent for coordinated metal. The separation of Co(II) from Zn(II), Ni(II) and Cu(II) was also studied, but the selective recovery of the metals was possible using the multi-stage stripping process.
“…A variety of sorbents show high affinities towards a variety of REEs with good capacities, rapid kinetics, and economics. Although many REE adsorbents have been studied [49][50][51][52][53][54][55][56][57][58][59][60][61], to date, there is no adsorbent material in practical use.…”
The availability of rare earth elements from primary resources has come into question in the last two decades. This has sparked various government and industry initiatives to examine potential rare earth element resources apart from virgin ore bodies. Geothermal fluids are potentially significant sources of valuable minerals and metals, while co-recovery with geothermal energy production would be an attractive sustainable system. In this work, we give a brief survey of data collected on rare earth element concentrations in geothermal fluids. A survey of methods and technologies for extracting rare earth elements from geothermal is discussed along with the feasibility of recovering rare earth elements from geothermal brines. Based on the findings of this study, rare earth element extraction from geothermal fluids is technically possible, but neither economically viable nor strategically significant at this time.
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