Scandium Adsorption Research Articles

Study on adsorption of scandium by iminodiacetic acid resin TP207

Abstract Scandium (Sc) is a rare transition metal applied in unique electronic/alloy materials such as magnesium scandium alloy, aluminum scandium alloy, laser glass, superconductors, and electronic components. However, scandium is extremely hard to obtain. In this paper, the iminodiacetic acid resin TP207 was first applied for the recovery of scandium from a hydrochloric acid solution. The adsorption of Sc3+ by TP207 resin was analyzed by SEM-EDS, FT-IR, and XPS. It was found that the best adsorption time was 2 hours with the equilibrium adsorption rate reaching 99%. The saturated adsorption amount of resin was 0.05g/ml. This process involves the ion exchange of scandium ions with sodium ions on the resin and the chemisorption of scandium with the -COO- group. Furthermore, the TP207 resin exhibited a quasi-second-order kinetic mechanism towards Sc3+, which was the rate of adsorption is proportional to the concentration of the reactants. In addition, the adsorption of resin for Sc3+ is an endothermic reaction by calculating the thermodynamic parameters, and there is a 3.6% difference in adsorption efficiency between the two cycle experiments. In a word, the TP207 resin is a very promising adsorbent for Sc beneficiation from the HCl system.

Study on wetting mechanism of Sn3Sc alloy on silica and sapphire surfaces

To further investigate the wetting mechanism of filler alloys containing active elements on oxide ceramics surfaces, we prepared a new filler alloy (Sn-3at.%Sc filler alloy) containing trace rare earth elements by vacuum melting furnace. Under high vacuum, its wetting behavior on silica and sapphire substrates was studied using a modified sessile drop method. The final contact angles of liquid Sn-3at.%Sc filler alloy on silica and sapphire surfaces are 6.0° and 9.8°, respectively, showing good wetting properties, and exhibiting similar wetting behavior at the same temperature. The same interfacial product Sc2O3 was detected at the interface of Sn-3at.%Sc/silica and Sn-3at.%Sc/sapphire systems. However, thermodynamic and spreading analysis suggests that Sc2O3 is precipitated in different ways at the interface of the two systems. The former is generated by an interfacial reaction, while the latter precipitates during the cooling process. The wettability of the Sn-3at.%Sc/silica system may depend on the interaction between the interface reaction products and residual scandium adsorption at the solid/liquid interface, while the wettability of Sn-3at.%Sc/sapphire system may depend on the adsorption of Sc-O clusters at the interface. These findings provide a theoretical basis and design ideas for further development of tin-based filler alloys and design of new type filler alloys.

One-pot in situ construction of amido and hydroxyl co-modified layered double hydroxides for selective scandium adsorption

Amido and hydroxyl co-modified layered double hydroxides with high selective scandium adsorption performances were constructed via a one-pot in situ strategy.

Scandium Recovery from Aqueous Solution by Adsorption Processes in Low-Temperature-Activated Alumina Products.

In this paper, we studied the scandium adsorption from aqueous solutions on the surface of low-temperature-activated alumina products (GDAH). The GDAH samples are industrially manufactured, coming from the Bayer production cycle of the Sierra Leone bauxite as aluminium hydroxide, and further, by drying, milling, classifying and thermally treating up to dehydroxilated alumina products at low temperature. All experiments related to hydroxide aluminium activation were conducted at temperature values of 260, 300 and 400 °C on samples having the following particle sizes: <10 µm, 20 µm, <45 µm and <150 µm, respectively. The low-temperature-activated alumina products were characterised, and the results were published in our previous papers. In this paper, we studied the scandium adsorption process on the above materials and related thermodynamic and kinetic studies.

Selective adsorption and recovery of scandium from red mud leachate by using phosphoric acid pre-treated pitaya peel biochar

In recent years, the global demand for scandium has increased due to its essential role in the high-technology industry. Red mud leachates constitute a significant source of scandium and an efficient and environmentally friendly approach that attracted considerable interest. In this study, H3PO4 activated biochar (P40s) is manufactured from pitaya peel (PP) as a novel material to be used for scandium adsorption and recovery from red mud leachates. The material was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption isotherms, X-ray photoelectron spectroscopy (XRF), zeta potential, and element analysis (such as C, H, O, N and P) to characterize adsorbents. The results indicated that the phosphorus-containing functional groups were successfully introduced to improve the physicochemical properties of biochar. The pseudo-second-order kinetic model and Freundlich isotherm fit experimental data, verifying that the scandium adsorption by activated biochar is dominated by chemisorption and belongs to multilayer sorption. The maximal adsorption capacity of 750 °C calcinated H3PO4 activated biochar (P40-750) was 20.77 mg/g. Notably, the adsorbent was better for selective recovery of Sc3+ from Al3+, Fe3+, Dy3+, Y3+ coexistence ions. The separation coefficients (SF) of scandium for aluminum, iron, dysprosium, and yttrium are 137.03, 27.04, 77.74, and 208.25 times respectively, at pH3. Importantly, scandium is efficiently extracted from the leaching solution of red mud with an 83% recovery rate. Meanwhile, P40-750 exhibited a stable scandium adsorption capacity after 5 adsorption/desorption cycles. Overall, P40-750 could be considered a low-cost and environment-friendly biosorbent for recovering scandium from red mud leaching solution.

Adsorption of Scandium and Yttrium from Aqueous Solutions by Purolite C100Na Resin: Equilibrium and Kinetic Modeling

ABSTRACT: Adsorption of Sc from single and bi-component Sc-Y solutions by Purolite C100Na was studied experimentally and kinetic and thermodynamic characteristics are described. The extended Freundlich isotherm was found to be successful in validating the experimental results. Moreover, curve fitting the time-dependent data into different kinetics mechanisms showed a satisfactory correlation with the pseudo-second-order model. Binary system results show a decrease in Sc adsorption capacity of the absorbent in the presence of secondary ions because of competition for adsorption sites. Furthermore, thermodynamic parameters indicate similarity of reaction mechanisms for both single and binary systems, with Sc absorption adversely affected by temperature. Data from experiments on synthetic electrolytes with Y/Sc ratio of 5 found in actual mining copper leach solution were used for extracting scandium by circulating mine-leach solution through a resin column. The results demonstrate a preferential collection of Sc ions despite the fivefold concentration of Y over Sc. The elusion studies showed that the yttrium desorption peak occurs before that of Sc which, corroborates the adsorption isotherm findings. This results in a 180 mgL-1 Sc rich solution or 60:1 concentration ratio over the original copper leach solution.

First-principles modeling of X-ray absorption spectra enlightens the processes of scandium sequestration by iron oxides

Abstract Scandium is often associated with iron oxides in the environment. Despite the use of scandium as a geochemical tracer and the existence of world-class supergene deposits, uncertainties on speciation obscure the processes governing its sequestration and concentration. Here, we use first-principles approaches to interpret experimental K-edge X-ray absorption near-edge structure spectra of scandium either incorporated in or adsorbed on goethite and hematite, at concentrations relevant for the environment. This modeling helps to interpret the characteristic spectral features, providing key information to determine scandium speciation when associated with iron oxides. We show that scandium is substituted into iron oxides at low concentrations without modifying the crystal structure. When scandium is adsorbed onto iron oxide surfaces, the process occurs through outer-sphere complexation with a reduction in the coordination number of the hydration shell. Considering available X-ray absorption spectra from laterites, the present results confirm that scandium adsorption onto iron oxides is the dominant mechanism of sequestration in these geochemical conditions. This speciation explains efficient scandium recovery through mild metal-lurgical treatments of supergene lateritic ores. The specificities of scandium sorption mechanisms are related to the preservation of adsorbed scandium in million-years old laterites. These results demonstrate the emerging ability to precisely model fine X-ray absorption spectral features of trace metals associated with mineral phases relevant to the environment. It opens new perspectives to accurately determine trace metals speciation from high-resolution spatially resolved X-ray absorption near-edge structure spectroscopy in order to constrain the molecular mechanisms controlling their dynamics.

Bisphosphonate modified mesoporous silicon for scandium adsorption

Abstract Scandium has several applications in advanced technology, but its wider utilization is restricted by the limited supply. Scandium exists in low concentration in ores and, therefore, the conventional extraction methods are difficult, uneconomical, and often hazardous to the environment. Adsorption is more sustainable method to extract scandium, because of low energy consumption and scalability. However, selectivity and stability of adsorbents are often inadequate. The present paper introduces a novel hybrid material as a robust adsorbent for efficient extraction of scandium. The material comprises of bisphosphonate molecules grafted on thermally carbonized surfaces of mesoporous silicon. The mesoporous framework was utilized to make the material water permeable to be used in a flow-through system, and the surface modifications made the material exceptionally stable even in harsh conditions. The material exhibited a remarkable selectivity towards scandium with a separation factor of 13, which is 3-fold higher compared with the commercial ion exchange resin Dowex 50WX8. Crucially, the hybrid material proved to be highly stable and reusable up to 50 adsorption/desorption cycles of scandium.

Separation and recovery of iron and scandium from acid leaching solution of red mud using D201 resin

Red mud is a byproduct of alumina refining of bauxite ores, and is a significant source for extracting scandium. However, a large amount of iron in red mud makes it difficult to recover scandium because Fe(III) and Sc(III) have similar physicochemical properties. In this study, a new method was developed for selective separation of iron and scandium in acid leachate of red mud using D201 resin. Theoretical calculations indicate that the ferric species mainly exists as FeCl3 or FeCl4− at chloride concentration above 6.65 mol/L, while scandium still exists as ScCl2+, making it possible to selectively separate iron from scandium through anion resin adsorption. The factors affecting the adsorption of iron and scandium such as chloride concentration, resin dosage, adsorption time, and temperature were evaluated in batch experiments. The Langmuir model was successfully applied to both iron and scandium adsorption, and the maximum adsorption capacities of iron and scandium are 147.06 and 0.95 mg/g, respectively, indicating a significant difference between iron and scandium. Raman analysis further demonstrates that the iron is adsorbed onto D201 resin as FeCl4− anion.

Scandium adsorption from sulfuric-chloride solutions with activated carbons

The study covers scandium adsorption in batch conditions by VSK, DAS and PFT activated carbon grades (Russia) of different origin (сoconut shell, аnthracite, thermoset waste, respectively) from sulfuric acid-chloride solutions (pH = 2) simulating the composition of the underground leaching solutions of polymetallic ores. It was found that scandium adsorption by DAS and VSK carbons proceeds with the highest distribution coefficients (133 and 45.8 cm3/g, respectively). Isotherms of scandium adsorption with these carbons are linear and described by the Henry equation with constants 133 ± 21 and 46 ± 7 cm3/g, respectively. A limited solution volume method was used to obtain the integral kinetic curves of scandium adsorption. Their linearization according to the kinetic models of the pseudo-first, pseudo-second order, the Elovich model and the Weber–Morris intra-particle diffusion model indicates that the kinetics of scandium adsorption with VSK carbon having a higher correlation coefficient (0.999) is described using the pseudo-second order model. Description of the kinetic data obtained during the adsorption of scandium with DAS carbon showed that for all the models used the correlation coefficient is low (&lt;0.939), while the highest value is observed when using the intra-particle diffusion model. It was suggested that the scandium adsorption process occurs in the mixed diffusion region. The possibility of scandium elution from VSK and DAS carbons with sodium carbonate solution (10 %) was studied in batch conditions, where the degree of scandium desorption in two stages of elution was 84.0 and 90.4 %, respectively.

Comparative Evaluation of Adsorption of Rare-Earth Elements in Some Soil Types

Competitive adsorption of scandium, yttrium, and lanthanides was studied for soddy-podzolic and gray forest soils and for leached chernozem. The chemical behavior of scandium significantly differs from that of other rare-earth elements (REEs) by the quick reaching of equilibrium in the soil–solution system and by the fact that its adsorption is not described by the Langmuir equation unlike yttrium and lanthanides. Individual chemical properties of REEs are the most pronounced in the experiments on competitive adsorption. In the yttrium–lutetium sequence, there is a tendency for a gradual decrease in the maximal adsorption capacity (from 0.025 to 0.010 mmol/kg in soddy-podzolic soil and from 0.100 to 0.050 mmol/kg in leached chernozem) and more pronounced increase in the Langmuir adsorption constants (from 5000 to 25 000 L/mmol in soddy-podzolic soil and from 5000 to 40 000 L/mmol in leached chernozem). This reflects the competition between different elements for soil sorption sites, which is directly related to the change in ionic radii of the elements (so-called “lanthanide contraction”). Unlike other soils, leached chernozem absorbs a large amount of REEs and provides their stronger fixation.

Solid-solid dewetting of scandium thin films on the W(100) surface observed using emission microscopy

Several operating modes of cathode lens emission microscopy are used to observe scandium on W(100), including mirror microscopy, thermionic emission microscopy, and low energy electron diffraction. Scandium thin films are deposited by thermal evaporation from a metal source onto W(100). The scandium films on W(100) are observed to dewet from the W(100) surface and to form droplets when the surface is heated: the dewetting temperature is thickness dependent and spans a range from 500 to 900 °C, which is far below the melting temperature (1541 °C). Thinner films produce smaller droplets; a range of film thicknesses from 5 to 30 nm was tested. X-ray photoelectron spectroscopy of the scandium films exposed to oxygen was also measured in order to understand the function of scandium in thermionic cathodes. The shift of the W 4f peaks upon oxygen absorption, scandium adsorption, and subsequent heating indicates that oxygen preferentially bonds to scandium. The shift in the scandium 3p level indicates formation of Sc2O3.

Адсорбция скандия из серно-хлоридных растворов с помощью нанокомпозита ПАНИ/УНТ

Адсорбция скандия из серно-хлоридных растворов с помощью нанокомпозита ПАНИ/УНТ

Kinetics of the adsorption of scandium and cerium ions in sulfuric acid solutions on a nanomodified activated carbon

The adsorption of rare-earth elements (cerium and scandium) on pristine and nanomodified activated carbons in sulfuric acid solutions simulating the composition of multi-metallic ore leaching solutions was studied. New applications of scandium and cerium in industry, which constitute the main segment of wastewater pollution, were described. Various materials used to extract target metals were considered. A hybrid material based on carbon nanotubes-modified coconut shell activated carbon was proposed, and its structural and physico-chemical characteristics were described. The kinetic parameters of the adsorption of the rare earth elements studied, as well as adsorption rate constants, were determined. The optimum adsorption time was found to be 60 min. It was established that the process of adsorbing the cerium and scandium ions is driven by mixed diffusion, and the adsorption kinetics can also be satisfactorily described using the pseudo-first order model for all the ions. Thus, both physical adsorption and chemical interactions among the metal ions and the adsorbent functional groups can be assumed to take place during the extraction of the cesium and scandium ions.

Adsorption of Scandium and Neodymium on Biochar Derived after Low-Temperature Pyrolysis of Sawdust

The objective of this study was to investigate the adsorption of two rare earth elements (REEs), namely scandium (Sc) and neodymium (Nd), on biochar produced after low temperature pyrolysis (350 °C) of wood sawdust. The biochar was characterized with the use of several analytical techniques, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis, while the pH at point of zero charge (pHPZC) was also determined. The experimental conditions were: absorbent concentration 1–10 g·L−1, REE concentration in solution 20 mg·L−1, contact time for equilibrium 24 h, temperature 25 °C and stirring speed 350 rpm. The efficiency of biochar was compared to that of a commercial activated carbon. Geochemical modelling was carried out to determine speciation of Nd and Sc species in aqueous solutions using PHREEQC-3 equipped with the llnl database. The experimental results indicated the potential of low temperature produced biochar, even though inferior to that of activated carbon, to adsorb efficiently both REEs. The equilibrium adsorption data were very well fitted into the Freundlich isotherm model, while kinetic data suggested that the removal of both REEs follows the pseudo-second order kinetic reaction. Finally, the most probable adsorption mechanisms are discussed.

Grain-boundary internal friction of yttrium- or scandium-microalloyed copper

The influence of intercrystalline internal yttrium or scandium adsorption on the internal friction of copper microalloyed by yttrium or scandium is studied. Grain-boundary and “impurity” grain-boundary internal friction peaks of relaxation nature are detected. The binding energies of yttrium and scandium atoms to grain boundaries in copper are estimated using the results of measuring the grain-boundary internal friction.

Development of novel adsorbent bearing aminocarbonylmethylglycine and its application to scandium separation

BACKGROUND Scandium (Sc) is an important metal element in high-technology industries and the demand for Sc has been increasing annually. However, because metallurgical processes for its purification and recovery are complex, an effective technique for its separation is required. This paper reports on the development of novel adsorbents that are capable of separating Sc efficiently. RESULTS Novel adsorbents were prepared by introducing aminocarbonylmethylglycine functional groups onto two types of support materials, silica gels for determining suitable preparation conditions and an organic resin for practical use. Scandium adsorption and separation were carried out in sulfuric media using these adsorbents. The adsorbents exhibited high selectivity to Sc from Mg, Al, Ca, Cr, Mn, Co and Ni except for Fe(III). Adsorption–desorption experiments were conducted to examine the adsorbent reusability. The adsorbents showed similar results in reuse tests without any obvious loss. CONCLUSIONS Aminocarbonylmethylglycine functional group introduction proved effective and efficient for Sc adsorption. The newly synthesized adsorbents showed high affinity for Sc and Fe(III). Sc was separated selectively from Fe by reducing Fe(III) to Fe(II) because the adsorbent showed no affinity for divalent Fe(II). The new resin based adsorbent can be used for the practical separation of Sc. © 2016 Society of Chemical Industry

Study of adsorption behavior of a new synthesized resin containing glycol amic acid group for separation of scandium from aqueous solutions

A new synthesized resin containing glycol amic acid was used for separation of scandium from a model solution containing scandium, cerium, lanthanum, and aluminum. The resin shows the possibility of separating scandium from the mixture. Adsorption selectivity for scandium over the other metals was obtained at pH1. The kinetics of adsorption of scandium by the resin was slow, and a contact time of 24h was chosen in this study. The adsorption capacity of the resin for scandium in a column configuration was 7.0mgSc/mL. Scandium could be eluted from the loaded resin using 2.0M HCl solution at 80°C, and the highest enrichment point of scandium reached 540mgSc/L, which is 27 times greater than the initial scandium concentration, respectively. The results show that the resin has potential for use in the recovery of scandium from aqueous solutions generated in the processing of monazite.

Synthesis and characterization of lysine-modified SBA-15 and its selective adsorption of scandium from a solution of rare earth elements

A novel lysine-functionalized mesoporous material was synthesized using a facile two-step post-grafting method, selectively adsorbing scandium from aqueous solution.

Synthesis of Highly-Selective Fibrous Adsorbent by Introducing 2-Ethylhexyl Hydrogen-2-Ethylhexylphosphonate for Scandium Adsorption

2-ethylhexyl hydrogen-2-ethylhexylphosphonate (EHEP) is commonly used as a metal extractant because it has a particular affinity for rare-earth metals like Scandium (Sc). To develop a highly-selective adsorbent of Sc(III), EHEP was introduced as a functional group onto a polyethylene fabric with radiation-induced graft polymerization(RIGP). The adsorption performances for Sc(III) were evaluated with aqueous solutions containing Sc(III) and Fe(III) in bath and column tests. As a result of column test, the adsorption capacities of Sc(III) and Fe(III) until the bed volume reached 5000 were 5.22 and 0.12 mg/g, respectively. It means that the amount of collected Sc(III) by the EHEP adsorbent was approximately 44 times higher than that of Fe(III). These results indicate that the grafted adsorbent containing EHEP has an extremely high selectivity for Sc(III) adsorption.