Chelating Ion Exchange Research Articles

Selective separation of light and heavy rare earth elements from acidic mine waters by integration of chelating ion exchange and ligand impregnated resin

This study addresses the potential of sourcing Critical Raw Materials (CRMs) using Acidic Mine Waters (AMWs) as a secondary resource. AMWs, often viewed as waste, contain valuable metals like zinc and copper, as well as critical metals like magnesium and cobalt. Moreover, recent studies also reported the presence of Rare Earth Elements (REEs) at concentrations (mg/L) that make their extraction both technically and economically viable. The research focuses on a circular process to recover these metals from AMWs, specifically from the Aznalcóllar open-pit mine, which contains 216 mg/L of Al, 47 mg/L of Fe, 547 mg/L of Zn, and 18.56 mg/L of REEs. The proposed method involves pre-treating the AMW to remove Fe and Al, achieving removals of over 99.9 % and 90 %, respectively, at pH 4.5. Following this, transition metals like Zn, Cd, and Cu were removed as sulphides with a removal efficiency exceeding 99 %. This pre-treatment step reduced the concentration of competing metals in the ion-exchange process, thereby enhancing the recovery and purity of REEs. To separate heavy and light REEs, two types of resins in series were used: an impregnated resin (TP272) and a chelating resin (S930), which can be regenerated using sulphuric acid (H2SO4). The final recovery of REEs as oxalates was achieved using oxalic acid and ammonia at pH 1, with further optimization of the elution process to minimize ammonia consumption and undesired precipitation of other oxalates. Finally, REE oxalates with purities exceeding 90 % were obtained. This research demonstrates a sustainable method for efficiently recovering valuable REEs from AMWs, while also addressing environmental concerns related to hazardous sludge generation.

Removal of Heavy Metal Ions from Water Using Chelating Copolymer Resin-IV Derived from 2-Hydroxy, 4-Methoxybenzophenone, 1, 5-Diaminonaphthalene and Formaldehyde

The resin 2-H, 4-MBP-1,5-DANF-IV was synthesized by the condensation of 2-hydroxy, 4-methoxybenzophenone and1, 5-diaminonaphthalene with formaldehyde in the presence of hydrochloric acid as a catalyst. The resin was characterized by elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and UV-Visible spectral studies. The chelation ion-exchange properties was studied for Ni2+, Cu2+, Co2+, Zn2+ and Pb2+ ions employing a batch equilibrium method. It was used to study of the selectivity of metal-ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strength.The resin depicted a higher selectivity for Cu2+ and Ni2+ ion than for Co2+, Zn2+ and Pb2+ ions.

Integrating diffusion dialysis for sustainable acid recovery from ion exchange regeneration stages: Characterization of metal and non-metal ions migration

Seawater mining presents a potential option for recovering the European Union’s Critical Raw Materials (CRMs), but direct extraction from seawater is challenging due to their low concentrations, as most of them are Trace Elements (TEs) (at levels of mg/L or µg/L). Saltworks bitterns (ultraconcentrated brines resulting from the sea salt production process) offer an alternative solution, naturally concentrated up to 40 times more than seawater. These bitterns can be further processed with chelating Ion Exchange (IX) sorbents to selectively extract TEs. However, this process requires an acidic elution stage with strong acids, followed by neutralization, to recover TEs through precipitation, demanding extensive chemicals consumption. Diffusion Dialysis (DD) could be used to recover the excess acid without external reagents, using an acid-resistant Anion Exchange Membrane (AEM). This study evaluates DD through batch and once-through tests for acid recovery from simulated IX eluate generated in the elution stage of TEs (B, Ga, Ge, Co, Sr) recovery from saltworks bitterns.Batch tests achieved high recoveries for HCl (45–50 %) and H2SO4 (30–37 %), being the theoretical maximum attainable recovery equal to 50 %. B and Ge only partially permeated through the membrane (82 % rejection) by a diffusion mechanism in their neutral form (H3BO3(aq), H4GeO4(aq)). Ga, Co and Sr, in cationic form, were highly rejected (>96 %). Permeability followed the order Ga < Sr < Co ≪ Ge < B, due to the relevant charge and size. HCl permeability correlated linearly with concentration, while H2SO4 was inversely proportional. Once-through tests showed higher acid (74 % HCl, 62 % H2SO4) and oxoacid (66 % H3BO3(aq), 52 % H4GeO4(aq)) recovery at a low specific flow rate, or apparent flux, (0.38 L/(m2membrane·h)) due to increased residence time. Water to acid flow rate ratios did not affect species transport when an excess of water was guaranteed. Conversely, an influence was observed when the ratio was below 1, with a minimum at 0.18, where a very low passage of species was observed due to the reduced dilution volume of the dialysate solution (water). A 1D transport model, incorporating the solutes permeabilities determined experimentally, effectively described the system performance, especially for HCl and B, albeit slightly overestimating the other TEs’ transport.

Selective recovery of copper from copper tailings and wastewater using chelating resins with bis-picolylamine functional groups

Industrial and mining wastewater, along with copper tailings, are typically highly acidic and contain copper and other heavy metals, which may contaminate and damage the environment. Copper (Cu) is, however, a valuable metal, making its removal and recovery from such wastewater and tailings environmentally and economically advantageous. Chelating ion exchange resins featuring bis-picolylamine functional groups are especially suitable for application requiring selective recovery of Cu(II) from highly acidic media. In this study, and for the first time, the kinetics, binding capacity and selectivity of Lewatit MDS TP 220 chelating resin towards Cu(II) are reported. The resin was characterized by Zeta potential, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Factors including pH, initial concentration, contact time, temperature, and selectivity were investigated to assess the adsorption performance of the chelating resin. The adsorption kinetics tests revealed fast adsorption within the first 5–30 min and fitted the pseudo-second-order model, signifying chemisorption process. The adsorption isotherm followed the Langmuir model, implying monolayer adsorption process. The maximum adsorption capacity (qm) for Cu(II) determined by the Langmuir model was 103.9 mg/g. The adsorption thermodynamics showed an endothermic and spontaneous adsorption. FTIR and XPS studies suggested coordination or chelation as the possible adsorption mechanism. Lewatit MDS TP 220 exhibited excellent Cu(II) adsorption, desorption with 2 M ammonium hydroxide (NH4OH), and selectivity in multi-metal ions solution. Additionally, the resin demonstrated excellent reusability after five regeneration steps. This chelating resin is a potential adsorbent for effective and recurrent recovery of Cu(II) from copper tailings and wastewater, thereby contributing to environmental remediation.

Separation of Boron and Arsenic from Geothermal Water with Novel Gel-Type Chelating Ion Exchange Resins: Batch and Column Sorption-Elution Studies

In this research, the removal of boron and arsenic from geothermal water was examined by using novel N-methyl-d-glucamine functionalized gel-like resins (abbreviated as 1JW and 2JW) synthesized by the membrane emulsification method. The outcomes were compared with those of commercially available boron selective chelating ion exchange resin (Diaion CRB 05). According to the results obtained with the novel resins, it was possible to reduce both boron and arsenic concentrations in geothermal water by using these novel gel-like chelating resins below their permissible levels for agricultural irrigation (&lt;1 mg B/L) and drinking water (&lt;0.01 mg As/L) by using the batch method. The optimum resin concentration required for almost complete boron removal (more than 95%) with the two chelating resins was determined to be 2 g/L. The novel gel-like chelating resins 1JW and 2JW achieved 94% of arsenic removal by using the resin concentration of 8 g/L, while the required resin concentration was 32 g/L for 94% of arsenic removal using commercially available Diaion CRB05 resin. In addition, the column performance characteristics of the novel chelating resins for the separation of boron were studied, and the results were compared to those obtained with Diaion CRB05. According to the column data obtained, the total resin capacities of the Diaion CRB05, 1JW, and 2JW resins were calculated as 6.29, 5.08, and 4.64 mg B/mL-resin, respectively.

Gold recovery from synthetic mine tailings leachate using chelating ion exchange resins with thiosulfate-thiourea lixiviant

Recovery of gold from mining tailings is important economically and environmentally in the mining industry. With a limited amount of mineable gold remaining, the process of recovering gold from mine tailings needs development. This paper will specifically investigate the recovery of gold using ion-exchange resins in a thiosulfate-thiourea lixiviant solution. A range of resins of different functionalities: Purolite® A200 (Type II quaternary ammonium), Lewatit® MonoPlus TP 214 and Puromet® MTS9140 (thiourea), Dowex™ M-4195 (bis-picolylamine) and Lewatit® VPOC 1026 (di(2-ethylhexyl)phosphate- D2EHPA) were assessed for their gold uptake capabilities via dynamic column experiments. A mixed-metal solution was used to accurately simulate the spent lixiviant from thiosulfate/thiourea leaching of mine tailings. All resins showed selectivity towards gold over the numerous other metals in solution, which was believed to be due to the stability of aqueous gold thiourea complexes. Puromet® MTS9140 had the highest gold capacity, with a calculated uptake capacity of 41.6 mg/L. Modified-Dose Response (MDR), Bohart-Adams and Yoon-Nelson models were used to describe the data; the MDR model being the most successful.

Thermal Behaviour and Sorption Studies of Ion-Exchange Resin

Copolymer resin 2,4-DAPOF-II has been synthesized by condensation polymerization and its composition was determined on the basis of elemental analysis. Non-aqueous conductometric titration was used to determine the average molecular weight and the intrinsic viscosity was also determined. The formation of copolymer resin was confirmed by FT-IR, 1H-NMR and 13C-NMR spectroscopy. The semi-crystalline nature of synthesized copolymer was established by Scanning electron microscopy (SEM). Thermal degradation curve has been discussed with minute details by applying Freeman-Carroll8, Sharp-Wentworth47, Friedman and Chang equations9 to evaluate the kinetic parameters i.e. activation energy (Ea), order of reaction (n) and frequency factor (z). This copolymer is proved to be selective chelating ion exchanger for certain metal ions such as Fe3+, Co2+, Cd2+ and Pb2+. A batch equilibrium method was employed to study the selectivity of metal ion uptake involving the measurements and distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range, shaking time and in media of various ionic strengths.

Chromium (III) adsorption from the phosphoric acid medium using DETA grafted Merrifield resin

To selectively remove Cr (III) from synthetic phosphoric acid solution, a chelating ion exchanger was developed through Merrifield resin (MHL) functionalization with diethylenetriamine (DETA). The functional moieties of the grafted Merrifield resin were characterized and confirmed by means of Fourier-transform infrared spectroscopy. The morphological changes before and right after functionalization were visualized with Scanning electron microscopy and enhanced amine content was confirmed via energy dispersive X-ray. To assess the effectiveness of the MHL-DETA in the extraction of Cr (III) from a synthetic phosphoric acid solution, batch shaking adsorption tests were conducted through optimizing different factors such as contact time, metal ion concentration and temperature. According to our findings, higher adsorption was achieved when increasing contact time and decreasing metal ion concentration, while temperature variation doesn't affect much the process. The higher sorption yield was found to be 95.88% attained within 120min at room temperature without varying the solution's pH. Under optimum conditions (120min, 25°C and 300mg. L-1), the total sorption capacity was reported to be 38.35mg. g-1. The system's adsorption behavior was found to be consistent with the Langmuir isotherm and the pseudo second-order model accurately described the kinetic data. In this view, Merrifield resin functionalized with DETA could be used as a promising adsorbent material for Cr (III) adsorption from synthetic phosphoric acid medium.

Iminodisuccinic acid (IDHA) as an effective biodegradable complexing agent in the adsorption process of La(III), Nd(III) and Ho(III) ions

Environmental pollution and the continued depletion of many deposits have made the recycling of used materials an urgent need. An important aspect of this topic is the development of alternative compounds with a more favourable environmental profile compared to those currently in use. Indeed, when designing such processes, the negative human impact on the environment should be mitigated as much as possible. This paper presents the results of a study on the application of biodegradable complexing agent iminodisuccinic acid (IDHA) for the recovery of La(III), Nd(III) and Ho(III) by adsorption (single-component systems, static and dynamic methods) using various types of ion exchangers. The results obtained allow to determine the optimal process conditions and show that the chelating ion exchanger Purolite S957 has the highest adsorption capacity related to the La(III) complexes (142.29 mg/g), while the Nd(III) and Ho(III) complexes adsorb with the highest efficiency (161.04 mg/g for Nd(III) and 201.74 mg/g for Ho(III)) in the cation exchanger Lewatit SP112. According to the desorption studies the adsorbents are characterized by a large regeneration capability. This paper also presents the characterization of the physicochemical properties of the applied ion exchangers and the analysis of the binary systems (Ln(III)-IDHA) to determine the overall stability constants of the complexes using the potentiometric methods. Biodegradable IDHA was used to this aim.

Synthesis, characterisation, ion chelation exchange capability and antibacterial properties of the &lt;em&gt;o-cresol-formaldehyde-catechol-&lt;/em&gt;based copolymer

An ion exchange resin chelator was synthesized from o-cresol, catechol and formaldehyde through the condensation process in the molar ratio of 1:3:5 in the presence of 1 M hydrochloric acid as a catalyst. The resulting copolymer was characterized by IR spectral data. The cation exchange capacity was measured; the effect of metal ion concentration, pH effect, and the ratio of the cation exchange reaction were studied. The chelation ion-exchange properties were also studied with the batch equilibrium method. The formed copolymer chelation ion-exchange properties of the copolymer were analyzed for Cd²⁺, Cr²⁺, Fe²⁺ and Mg²⁺ ions. The resin was proved selective chelating ion- exchange copolymer for the above metals. The study was carried out over a wide pH range and in media of various ionic concentrations for the metals. The antibacterial properties of the synthesized resin were also investigated, using the well diffusion method for the gram-positive bacteria, <em>Staphylococcus aureus </em>and the gram-negative bacteria <em>E coli. </em>The results showed a significant inhibiting effect against the tested bacteria, against the formed resin copolymer.

Green citric acid in the sorption process of rare earth elements

In this study the effects of citric acid (CA) as a biodegradable complexing agent in the sorption process of La(III), Nd(III) and Ho(III) ions (single component systems) on various types of ion exchangers (chelating ion exchangers, cation exchanger, strongly and weakly basic polystyrene and polyacrylate anion exchangers) were investigated. The effects of pH, Ln(III):CA molar ratio, phase contact time and initial concentrations as well as temperature on the adsorption capacity were analysed. The optimal process conditions were also determined which varied depending on the ion exchanger and the metal ion. The process was fast in all systems (up to 60 min). The sorption data was analysed using the pseudo-first order (PFO), pseudo-second order (PSO), intraparticle diffusion (IPD), Boyd and Dumwald–Wagner (DW) kinetic models as well as the Langmuir, Freundlich, and Temkin isotherm models. Among the studied adsorbents, the highest adsorption capacity was obtained for the Purolite S957 chelating ion exchanger which was 162.04 mg/g for the La(III) complexes, 142.65 mg/g for the Nd(III) complexes and 180.26 mg/g for the Ho(III) complexes. Reusability of ion exchangers in the desorption studies was also evaluated as a sustainable approach. Moreover, dynamic experiments were performed using the columns set. The Thomas, Adams–Bohart, Yoon–Nelson and Wolborska models were applied to the experimental data to predict the dynamic behaviour of fixed bed columns. The physicochemical properties of adsorbents were characterized by scanning electron microscopy (SEM), pHpzc, and Fourier transform infrared spectroscopy (FTIR). The binary complexes of Ln(III) ions with CA at various metal:ligand ratios were investigated using the potentiometric method. The overall stability constants of the complexes were determined.

Synthesis and chelate ion exchange properties of copolymer resin: 8-hydroxyquinoline-5-sulphonic acid-catechol-formaldehyde

The sample 8-hydroxyquinoline-5-sulphonic acid-catechol-formaldehyde has been organized by using the condensation of 8-HQ-5-SACF-catechol-formaldehyde in the presence of (1:1:2M) ratios and in 2M HCl. The resin become categorised by using UV-seen, IR and proton NMR spectral research to show the structure. The copolymer resin has showed to be a discerning chelate ion alternate resin for a few metals. Chelate ion trade properties of this sample were experimented for the metals as copper, cobalt, nitrate, zinc and lead in exclusive with electrolyte concentrations, time durations and wide pH variety become delivered out by means of batch equilibrium approach. The above resin displays higher selectivity for copper and nitrate metals ions than for cobalt, zinc and lead metal ions. The measurement of distribution as a pH character determines amount of metals absorption by copolymer increases with increasing local pH.

Studies of chelation ion-exchange properties of copolymer resin derived from 1,5-diaminonaphthalene, 2,4-dihydroxy- propiophenone and formaldehyde

The copolymer 2,4-DHP-1,5-DANF-I has been synthesized by the condensation of 2,4-dihydroxypropiophenone, 1,5-diaminonaphthalene and formaldehyde in the presence of 2 molar HCl as a catalyst with 1:1:2 molar proportion of reactants. The resin has been characterized by various spectral techniques such as elemental analysis, FT-IR, 1H NMR. The ion-exchange properties of the copolymer resin for specific metal ions viz. Ni2+, Cu2+, Co2+, Zn2+ and Pb2+ ions was evaluated by a batch equilibrium method. The study was extended to three variations: evaluation of metal ion uptake in the presence of different electrolytes at different concentrations; evaluation of metal ion uptake at different pH; and evaluation of metal ion uptake at different times. From the results it was observed that the copolymer resin acts as an effective chelting ion-exchanger. Copolymer shows a higher selectivity for Cu2+ and Ni2+ ion than for Co2+, Zn2+ and Pb2+ ions.

An Eco-Friendly Terpolymer Resin: Synthesis, Characterization and Ion‐Exchange Properties

2, 2’- Biphenol-Hexamethylenediamine-formaldehyde Terpolymers (BPHDF) were synthesized by the condensation of 2, 2’- Biphenol, Hexamethylenediamine, and formaldehyde in the presence of acid catalyst with varying molar ratios of reacting monomers. Terpolymer composition has been determined on the basis of their elemental analysis and the number–average molecular weight of these resins was determined by conductometric titration in nonaqueous medium. The viscosity measurements were carried out in N, N-dimethyl formamide which indicate normal behaviour. IR spectra were studied to elucidate the structure. The terpolymer resin has been further characterized by UV–visible and 1H-NMR spectra. The surface morphology of the terpolymer resin was examined by scanning electron microscopy. One of the important applications of these terpolymers is their capability to act as chelating ion-exchangers. The newly synthesized terpolymers proved to be selective for chelating ion-exchange properties and showed a powerful adsorption towards specific metal ions like Co2+, Hg2+, Cd2+, Pb2+. A batch equilibration method was adopted to study the selectivity of the metal ion uptake involving the measurement of the distribution of the given metal ion between the polymer sample and a solution containing the metal ion over a wide range of concentrations and pHs of different electrolytes. The terpolymers showed a higher selectivity for Co2+&gt; Hg2+&gt; Cd2+&gt; Pb2+.It is also observed that the amount of metal ions absorption by the BPHDF terpolymer resins increases in the order: BPHDF-3 &gt; BPHDF-2 &gt; BPHDF-1 due to introduction of more and more phenolic groups in terpolymer resins from BPHDF-1 to BPHDF-3.

Recovery of Rare Earth Elements from acidic mine waters by integration of a selective chelating ion-exchanger and a solvent impregnated resin

A polymeric ion-exchange resin, incorporating methyl-amino-phosphonic (TP260) functionalities, and a solvent impregnated resin (SIR) incorporating tri-methylpentylphosphinic acid (TP272), were evaluated for the selective separation of Rare Earth Elements (REE) from Transition (TE), post -Transition (PTE), and Alkaline Earth (AE) Elements in acidic mine waters (AMW). The influence of the functional groups nature and the acidity dependence were studied and their effects on efficiencies for REE removal and separation from TE/PTE were analysed Both resins provided good separation factors of REE from TE/PTE by acidity control of the treated effluent once Fe(III), the major component in AMW, had been removed by precipitation. The TP272 resin, containing tri-methylpentylphosphinic acid (Cyanex 272) onto the polymeric network, showed higher affinity towards Heavy REE (HRRE) than for Light REE (LRRE) by acidity control (pH>4).Higher pre-concentration factors were achieved for TP272 impregnated resin (e.g., 20–30) in comparison with the TP260 phosphonic resin (2−5), as the pH extraction window is in the moderate pH region (1−5). The integration in series of both resins could be used to separate and recover HREE and LREE from TE/PTE from AMW generated concentrates could be used to recover REE as secondary resources for the clean energy technology industry.

Studies on the Mechanism of Cu(II) Ion Sorption on Purolite S 940 and Purolite S 950.

The aim of the presented research was to investigate the mechanism of sorption of Cu(II) ions on the commercially available Purolite S 940 and Purolite S 950 chelating ion exchangers with the aminophosphonic functional groups. In order to understand better the sorption mechanism, the beads were cut with an ultramicrotome before and after the Cu(II) ion sorption process. The cut beads were examined by scanning electron microscopy (SEM) with an EDX detector. The performed linear profiles of the elemental composition allowed us to examine the depth with which the sorbed metal penetrates into. For further investigations concerning the mechanism of the sorption process, the Fourier transform infrared spectroscopy (FTIR) analysis using the attenuated total reflectance (ATR) technique and the X-ray photoelectron spectroscopy (XPS) methods have been used. The comparison of FTIR and XPS spectra before and after the sorption of Cu(II) ions showed that free electron pairs from nitrogen and oxygen in the aminophosphonic functional groups participate in the process of copper ion sorption. In addition, the microscopic studies suggested that the process of ion exchange between Na(I) ions and sorbed Cu(II) ions takes place on the Purolite S 940 and Purolite S 950. This study concerning the in-depth understanding the of Cu(II) sorption mechanism, using modern analytical tools and research methods could be very useful for its further modifications leading to the improvement of the process efficiency.

Sorption Recovery of Platinum Metals from Production Solutions of Sulfate-Chloride Leaching of Chromite Wastes

This paper discusses the scientific rationale for methods of platinum metals sorption centralization from saturated solutions with a high content of macrocomponents. Methods of sorption centralization of platinum and iridium using local anionites such as AH-31, AB-17-8, Purolite S985 are described. The sorbents used were conditioned to remove organic and mineral impurities. The sorption isotherms of platinum group metals 1/EC=f(1/Cp) at a temperature of 20 °C and a duration of 24 h were plotted. The data on the sorption recovery of platinum and iridium from individual and combined sulfate-chloride solutions were determined. Isotherms of iridium sorption from sulfate-chloride solution are formed. Results of the apparent sorption equilibrium constant and values of standard Gibbs energy (ΔG, kJ/mol) of ion exchange for sorption of platinum and iridium from individual and combined sulfate-chloride solutions are presented. Linearized isotherms and kinetic curves of joint sorption of platinum and iridium from sulfate-chloride solution are described. Comparative sorption of the platinum-group metals (PGM) by anionites AB-17-8 and Purolite S985 from sulfate-chloride solutions is shown. The sorption diagram of platinum and iridium from sulfate-chloride product solutions is presented. It has been revealed that complete recovery is achieved using chelation ion-exchange resin Purolite S985, with recovery of Pt up to 95% and Ir more than 73%. The sorption process is accompanied by intradiffusion constraints that are confirmed by the analysis of kinetic curves using Schmukler and Boyd–Adams models.

СИНТЕЗ И ИССЛЕДОВАНИЕ ХЕЛАТООБРАЗУЮЩИХ ИОНИТОВ НА ОСНОВЕ СОПОЛИМЕРОВ ЭПОКСИАКРИЛАТОВ

The possibilities of obtaining new chelating (complexing) ion exchangers based on copolymers of glycidyl methacrylate (GMA), methyl methacrylate (MMA), tripropylene glycol diacrylate (TPGDA), and oxyethylenediphosphonic acid complexone (OEDP) were studied. The optimal synthesis conditions and studied the physicochemical properties of the resin.To assess the acid-base properties of the synthesized polyelectrolytes, potentiometric studies were carried out, it was determined that the new ion exchangers have a medium acid character, and also belong to polyfunctional ion exchangers. The structure of the synthe-sized ion exchangers GMA-TPGDA-MMA: OEDP, GMA-MMA: OEDP was established by IR spectroscopy and elemental analysis. Studied the influence of the ratio of the initial reacting components, temperature and duration of the process on the static exchange capacity of ion exchangers. It was found that an increase in the amount of oxyethylenediphosphonic acid in the initial mixture in the reaction mixture from 1.0 to 3.0 mass parts leads to an increase in the capacity from 4.3 mEq / g to 6.2 mEq / g according to GMA-TPGDA- MMA: HEDP, from 4.8 mEq / g to 6.6 mEq / g according to GMA-MMA: HEDP. The chemical stability of the ion exchan-gers showed that the obtained ion exchangers are quite inert to chemical reagents. The most stable was the cation exchanger based on the ternary copolymer GMA-TPGDA-MMA: HEDP with a mass ratio of 1: 3. The degree of loss of capacity of the ion exchanger, obtained on its basis, does not exceed 9% when treated with solutions of acids, alkalis, and under the action of oxidizing agents, SEC practically does not change.

Adsorption of lanthanum and cerium on chelating ion exchange resins: kinetic and thermodynamic studies

ABSTRACT As the demand for rare earth elements (REE) increases in the coming years, techniques to obtain these elements from different sources may be explored. A hydrometallurgical route may achieve the sustainable approaches signed by countries. For this, separation techniques need to be explored, and chelating ion exchange resins are the most prominent. For this reason, to enhance the possibilities for REE separation, the main focus of this work was to study kinetics models and the thermodynamics of lanthanum and cerium adsorption at laboratory scale under industrially operating conditions. Three different functional groups were evaluated through the chelating resins M4195, TP207, and XUS43605. The effect of pH and resin dosage were evaluated, as well as the kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion) and thermodynamic parameters. The results presented here could be used for industrial applications. Pseudo-second order provided a better fit for both M4195 and TP207, and the intraparticle diffusion fitted better for XUS43605. Thermodynamic experiments have shown that the adsorption of lanthanum and cerium are spontaneous and endothermic. These findings represent the novelty of the present study since it could be used in selective separation of lanthanum and cerium onto chelating resins from primary and secondary sources.

Synthesis, characterization and Ion-exchange properties of 4, 4 oxy-dianiline, 2,6 diamino-pyridine with formaldehyde terpolymer

Abstract A new terpolymer ligand (DAPR) was synthesized based on condensation polymerization techniques. DAPR was named by 4,4 oxy-dianiline and 2,6 diamino-pyridine with formaldehyde. The taken monomers mole ratio is 1:1:2 in the reaction medium of Dimethylformamide (DMF). The solubility behaviour of the terpolymer samples have been studied in various solvents. The prepared terpolymer ligand was characterized by elemental analysis, FTIR, 1H & 13C NMR and TGA studies. The synthesized terpolymer ligand molecule formula identified by elemental analysis and the most probable structure confirmed by the spectral studies of FTIR, 1H & 13C NMR. The SEM image used to establish the outward of the ligand. The thermal decomposition and thermal strength of DAPR ligand was carried out by thermo gravimetric analysis (TG-DTA). The chelation ion exchange studies of the terpolymer for the definite metal ions were also carried out by batch equipoise way under the estimation of metal ion uptake at diverse electrolytes.