Lewatit TP Research Articles

Optimized Lithium(I) Recovery from Geothermal Brine of Germencik, Türkiye, Utilizing an Aminomethyl phosphonic Acid Chelating Resin

ABSTRACT This study investigates the performance of Lewatit TP 260 ion exchange resin for the efficient recovery of lithium (Li(I)) from geothermal water sourced from the Germencik Geothermal Power Plant in Türkiye. A series of batch sorption experiments were performed to evaluate the influence of key parameters, including resin dosage, solution pH, temperature, initial Li(I) concentration, and contact time, on the Li(I) recovery process. The optimal conditions were determined to be a resin dose of 0.5 g per 25 mL of geothermal water, pH in the range of 6–8, and a temperature of 25°C. Under these conditions, the resin achieved a maximum Li(I) recovery rate of 71% from the geothermal water. Sorption isotherms were further analyzed using the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. Among these, the Langmuir model provided the best fit (R² = 0.9841), suggesting a maximum sorption capacity (qm) of 4.31 mg/g. Continuous recovery experiments conducted in column mode confirmed the practical applicability of Lewatit TP 260, achieving a total sorption capacity of 0.41 mg Li(I)/mL resin. The findings exhibit the potential of this resin as a viable sorbent for sustainable Li(I) extraction from geothermal brines, supporting the development of green energy technologies and contributing to the circular economy.

High purity alumina production by leaching-ion exchange process: Design and flowchart proposal

Growing demand for high-purity Al2O3 for the electronic market and green energy production, allied with the need to decrease waste generation and dam use, will impact the future of mining, and new processes should be developed. The present study aimed to develop a hydrometallurgical process to obtain high-purity Al2O3 from bauxite. Among the samples studied, BX03 had the highest Al2O3 (63.8 %) and lowest Fe2O3 content (4.3 %). Different acids were evaluated – H2SO4, HCl, HNO3, and H3PO4 – and the H2SO4 reaction achieved all Al leaching with the best technical–economic analysis (TEA). Purification experiments were carried out with ion exchange resins in batch reactions. The best purification parameters were 4 h of contacting time and mass of resin/volume of solution ratio as 1/10 at 45 °C in two stages. The iminodiacetate resin (Lewatit TP 207) achieved the best results and removed all Fe ions without losses. High-purity Al2O3 was further obtained by precipitation with NH4OH after calcination. Considering the leaching step costs, the proposed process may achieve up to US$ 63,022.91 in profit.

Co-Extraction of Uranium and Mercury Using Ion Exchange from Cemented Radioactive Waste Sulfuric Leachate in Iodide Media

The production of medical isotopes in Chalk River Laboratories facilities (Chalk River, ON, Canada) has resulted in a large quantity of cemented radioactive waste (CRW) containing valuable elements such as uranium. From the perspective of recovering and ultimately recycling valuable elements from CRW, the solubilization of key constituents such as uranium, mercury, and cesium has been previously investigated using H2SO4/KI. However, to achieve recycling of these elements, separation must be performed as they are co-solubilized. In this study, the extraction of uranium and mercury by chelating resin Lewatit TP260 from surrogate cemented radioactive waste (SCRW) leaching solution in sulfuric media and in the presence of iodide was investigated. Extraction of U and Hg was assessed as a function of the concentration of KI (0.12 M to 0.24 M) used during the SCRW dissolution process. Continuous experiments showed that the Lewatit TP260 functional group, aminomethylphosphonic acid, had a high affinity for U. Mercury was also extracted onto the Lewatit TP260. However, the presence of iodide in the SCRW leaching solution increased the competition between the adsorbed mercury of the stationary phase and the iodide–mercury complexes of the mobile phase. Additionally, the reusability of the resin was tested through extraction and desorption cycles. Due to the presence of trivalent cation, the capacity of Lewatit TP260 for U and Hg decreases with the number of cycles.

Resources recovery-Separation and recovery of copper from desalination brine through Lewatit TP 207 resin.

Because of freshwater scarcity caused by extreme climate change, desalination technique has been developed in many countries to acquire freshwater. However, desalination plants worldwide not only produce freshwater but also generate large amounts of high salinity wastewater (brine). Brine discharge will decrease the concentration of dissolved oxygen in seawater and affect the organism's habitat. The only merit of the brine is that the concentrations of valuable metals in brine are higher than in seawater. Therefore, it is an opportunity to recover metals from brine and solve the environmental problem simultaneously. This study then aims to recover copper from brine through the ion exchange method. The research could be divided into three parts. To begin with, the saturated adsorption capacity of copper through Lewatit TP 207 resin was 30.58 mg/g, and the adsorption behavior was in accord with the Langmuir model. The optimal parameters of copper adsorption through the resin would be surveyed in the second part. The results demonstrated that 16.1 mg/l of copper could be adsorbed from brine under contacting period of 16 min, pH 14, L/S ratio of 2000, and temperature at 328 K. In addition, the thermodynamic parameters would also be explored to realize how the adsorption reaction was processed. Lastly, different agents and desorption parameters would be investigated to separate the copper from the resin. The copper compound and the resin could be obtained and regenerated after desorption. PRACTITIONER POINTS: Reusing desalination brine could reduce its amount of discharge and increase its value. A 16.1 mg/l of copper could be adsorbed from desalination brine through the Lewatit TP 207 system. The optimal parameters are contacting period of 16 min, pH 14, L/S ratio of 2000, and temperature at 328 K. After adsorbing, copper could be desorbed by HCl, and copper chloride could be acquired by vacuum drying the solutions. This is a method with the goal of laboratory-safe, low-cost, and high-energy efficiency.

Selective Chelating Resin for Copper Removal and Recovery in Aqueous Acidic Solution Generated from Synthetic Copper-Citrate Complexes from Bioleaching of E-waste

This research focused on batch experiment using a new generation of chelating resins via an ion exchange process to describe the metabolic adsorption and desorption capacity onto iminodiacetic acid/Chelex 100, bis-pyridylmethyl amine/Dowex m4195, and aminomethyl phosphonic/Lewatit TP260 functional groups in bioleaching. The results showed that Dowex m4195 had the highest performance of adsorption capacity for copper removal in both H+-form and Na+-form. Results for Lewatit TP260 and Chelex 100 revealed lower adsorption performance than results for Dowex m4195. The investigation of desorption from chelating resins was carried out, and it was found that 2 M ammonium hydroxide concentration provided the best desorption capacity of about 64.86% for the H+-form Dowex m4195 followed by 52.55% with 2 M sulfuric acid. Lewatit with 2 M hydrochloric acid gave the best desorption performance in Na+-form while Chelex 100 using hydrochloric at 1 M and 2 M provided similar results in terms of the H+-form and Na+-form. As aspects of the selective chelating resins for copper (II) ions in aqueous acidic solution generated from synthetic copper-citrate complexes from bioleaching of e-waste were considered, H+-form Dowex m4195 was a good performer in adsorption using ammonium hydroxide for the desorption. However, chelating resins used were subsequently reused for more than five cycles with an acidic and basic solution. It can be concluded from these results that selective chelating resins could be used as an alternative for the treatment of copper (II) ions contained in e-waste or application to other divalent metals in wastewater for sustainable water and adsorbent reuse as circular economy.

Selection of sorption materials for the extraction of nickel and cobalt from the ore of the Gornostaevskoye deposit

Oxidized nickel ores account for the majority of industrial ores suitable for nickel production. The processing of such ores using traditional pyrometallurgical technology is not economically viable due to the low nickel content. One of the most cost-effective methods of processing oxidized nickel ores is sulfuric acid leaching technology followed by sorption extraction. The aim of this work is to establish the kinetic and thermodynamic parameters of the sorption extraction of nickel and cobalt using iminodiacetate chelating ion-exchange sorbents from various manufacturers, to select a desorbing solution and to determine the degree of desorption. The sorption of nickel and cobalt was carried out in a weakly acidic medium from a model solution containing impurities of other metals in static and dynamic modes. The limiting sorption capacity for the studied sorbents is 18-26 mg/g for nickel and 1-2 mg/g for cobalt in the static mode. The sorption capacity in the dynamic mode for nickel is equal to 25.5 g/L for Purolite S 930, 29.2 g/L for Lewatit TP 207, 1.4 g/L, and 1.8 g/L for cobalt, respectively. The best desorption parameters are achieved when using a 2 M sulfuric acid solution. The degree of desorption for sorbents Purolite S 930 and Lewatit TP 207 exceeds 90%. The use of the Lewatit TP 207 sorbent for the extraction of nickel from the leaching solution of nickel ore of the Gornostaevskoye deposit in 5 cycles made it possible to obtain a commercial desorbate with a nickel content of 18 g/L. The use of a part of the commercial desorbate obtained in the previous cycle, further strengthened to the initial concentration of sulfuric acid, for re-extracting nickel from the saturated sorbent during a cyclic process leads to a deterioration in desorption characteristics. It is recommended to remove the commercial desorbate from the process after several cycles of desorption and supply new solution of sulfuric acid for desorption to restore the sorption parameters.

Medical Plant Extract Purification from Cadmium(II) Using Modified Thermoplastic Starch and Ion Exchangers.

Pure compounds extracted and purified from medical plants are crucial for preparation of the herbal products applied in many countries as drugs for the treatment of diseases all over the world. Such products should be free from toxic heavy metals; therefore, their elimination or removal in all steps of production is very important. Hence, the purpose of this paper was purification of an extract obtained from Dendrobium officinale Kimura et Migo and cadmium removal using thermoplastic starch (S1), modified TPS with poly (butylene succinate); 25% of TPS + 75% PBS (S2); 50% of TPS + 50% PLA (S3); and 50% of TPS + 50% PLA with 5% of hemp fibers (S4), as well as ion exchangers of different types, e.g., Lewatit SP112, Purolite S940, Amberlite IRC747, Amberlite IRC748, Amberlite IRC718, Lewatit TP207, Lewatit TP208, and Purolite S930. This extract is used in cancer treatment in traditional Chinese medicine (TCM). Attenuated total reflectance-Fourier transform infrared spectroscopy, thermogravimetric analysis with differential scanning calorimetry, X-ray powder diffraction, gel permeation chromatography, surface analysis, scanning electron microscopy with energy dispersive X-ray spectroscopy, and point of zero charge analysis were used for sorbent and adsorption process characterization, as well as for explanation of the Cd(II) sorption mechanism.

Removal of iron, aluminium, manganese and copper from leach solutions of lithium-ion battery waste using ion exchange

The shift to electric mobility necessitates recycling the metals from lithium ion battery waste. Ion exchange was studied for use in the removal of impurities from synthetic lithium ion battery waste leachate in laboratory-scale batch and column experiments. Aminomethylphosphonic acid functional chelating resin (Lewatit TP260) was capable of removing Fe, Al, Mn, and Cu from the leachate, while leaving valuable Co, Ni, and Li as a pure mixture in the raffinate. Increasing the pH up to 3 and the temperature to 60 °C improved the purity and productivity. Iron and aluminium could not be eluted efficiently by mineral acids, but an oxalate solution was found feasible. A two-step elution procedure, in which Cu and Mn are first removed with sulfuric acid, followed by Fe and Al removal with potassium oxalate, was successfully demonstrated. The suggested process produced a > 99.6% pure Li + Co + Ni solution (battery grade), along with a Mn and Cu rich sulfuric acid solution with Co as an impurity and an oxalate solution of Fe + Al as by-products. The productivities for these solutions were 0.39, 0.16, and 0.38 BV/h, respectively. The Co loss was very low (1.1%) as compared to previously suggested impurity removal processes using precipitation and solvent extraction. Moreover, Co can be easily recycled back to the ion exchange column feed after Mn and Cu are recovered as pure by-products.

Valorisation options for Zn and Cu recovery from metal influenced acid mine waters through selective precipitation and ion-exchange processes: promotion of on-site/off-site management options

Acid mine waters (AMWs), generated in the processing of polymetallic sulphides, contain copper and zinc as the main valuable transition metal ions, which are typically removed by liming, due to their great environmental impact. In this context, this work proposes the integration of selective precipitation (SP) and ion-exchange (IX) processes for the separation and recovery of both valuable metals to encourage on-site and off-site management options promoting valorisation routes. Thus, the main objectives of this work were (i) the selective removal of Fe(III) and Al(III), using NaOH under pH control (pH < 5) to avoid the precipitation of Cu(II) and Zn(II) and (ii) the evaluation of a solvent-impregnated resin (Lewatit VP OC 1026, named VP1026) and a cation IX resin (Lewatit TP 207, named TP207) for the sequential extraction of both metal ions from AMW (batch and column experiments).Results indicated that the metallic pollution load was mostly removed during the SP process of Fe(III) (>99%) and Al(III) (>90%) as hydroxylsulphates (e.g., schwertmannite and basaluminite). The metal extraction profiles were determined for both metals from pH 1 to pH 5 by batch experiments, and indicated that the best extraction of Zn(II) was obtained using VP1026, being higher than 96% (pH = 2.6–2.8), whereas TP207 extraction performance was optimal for Cu(II) extraction (>99%) at pH = 3–4. Moreover, in dynamic experiments using a fixed-bed configuration, it was possible to separate and concentrate Zn(II) (concentration factor = 10) and Cu(II) (concentration factor = 40) using VP1026 and TP207, respectively.Overall, the integration of SP and IX processes showed a great potential in the separation and recovery of valuable metals from mine waters to promote a circular economy, based on the management proposal for non-ferrous metallurgical industries. The recovered Zn-rich and Cu-rich sulphuric concentrated streams were theoretically evaluated for further on-site or off-site re-use treatments (e.g., electrowinning, precipitation, crystallization).

Hydrometallurgical Technology for Processing of Galvanic Sludges

The problem of processing galvanic sludges, formed as a result of neutralization of technological solutions and wastewater containing heavy non-ferrous metals is considered in this study. At present, sludges are transported to disposal area and are not used in any way. Typically, such sludges contain significant amounts of chromium and nickel, which creates environmental hazard. Investigated sludge contains up to 6,6% Ni and up to 7,4% Cr. The hydrometallurgical process to treatment of these sludges is carried out. Solutions of sulfuric acid and ammonia were used as lixiviants. It is shown that when using a solution of sulfuric acid with pH=1,5, extraction of up to 93,3% Cu, 70,2 Ni, 90,3 Zn is achieved. For selective nickel recovery sorption concentration by Lewatit TP207 is proposed.&#x0D; Keywords: Galvanic sludge, hydrometallurgy leaching, nickel, ion-exchange resin

Hydrometallurgical Technology for Processing of Galvanic Sludges

The problem of processing galvanic sludges, formed as a result of neutralization of technological solutions and wastewater containing heavy non-ferrous metals is considered. At present, sludges are transported to disposal area and are not used in any way. Typically, such sludges contain significant amounts of chromium and nickel, which creates environmental hazard. Investigated sludge contains up to 6.6% Ni and up to 7.4% Cr. The hydrometallurgical technology for processing of these sludges has been developed. Solutions of sulfuric acid and ammonia were used as lixiviants. It is shown that when using a solution of sulfuric acid with pH=1.5, extraction of up to 93.3% Cu, 70.2 Ni, 90.3 Zn is achieved. For selective recovery of nickel from leachates the process of sorption concentration by Lewatit TP207 is proposed.

Nickel sorption from solutions with high salt concentration

The object of the study is salt concentrates formed as a result of treatment of concentrated acidic and alkaline wastewater of galvanic processes, realized on Ural Optical & Mechanical Plant (Russia). Salt concentrates are to be disposed of as low-hazard substances, but periodically the presence of nickel ions in them was detected. Concentration of nickel ions reaches up to 0.3 g/L, the total salt content reaches 200 g/L. The possibility of sorption purification of salt concentrates from nickel on the aminocarboxylicionite Lewatit TP 207 was studied, and the capacitance characteristics of the ionite were determined. It is shown that a high salt background does not reduce the ion exchange capacity of ionite for nickel. The dynamic capacity of Lewatit TP 207 before the breakthrough was 0.155 g/g. Nickel desorption is carried out with 20% sulfuric acid. The maximum concentration of nickel in the eluates was 25.484 g/L. Such eluates can be returned to the nickel-plating bath. The technology of periodic ion-exchange purification of salt concentrates is proposed.

The study of the Kinetic Characteristics of Sorption of Scandium of Ion Exchanger Purolite MTS9580 from Return Circulating Solutions of Underground Leaching of Uranium Ores

This paper presents the results of a study of experiments on the sorption characteristics of phosphorus-containing ion exchangers Purolite MTS9580 (functional group ‒ derivatives of phosphonic acid) and Lewatit TP260 (functional group ‒ aminomethylphosphonic acid) on scandium. Using the method of low-temperature nitrogen adsorption, structural characteristics of selected ion exchangers Purolite MTS9580 and Lewatit TP260 respectively were measured. The specific surface of Purolite MTS9580 and Lewatit TP260 ion exchangers was measured as 5.1 and 4.5 m2/g, respectively. The obtained values indicate the presence of a macroporous structure in the ion exchangers. Experiments were carried out on the sorption of scandium and critical impurities in a static mode and dynamic mode while varying the acidity of the initial mother liquor of the sorption of uranium. Comparison of scandium sorption from pre-acidified uranium sorption mother liquor with Lewatit TP260 and Purolite MTS9580 ion exchangers showed an advantage for MTS9580 resin. The MTS9580 resin had an exchange capacity of 200 mg Sc/dm3 versus 59.7 mg Sc/dm3 for TP260. The dynamic exchange capacity of Purolite MTS9580 is much lower in relation to harmful impurities as Al, Fe, Ca, etc.

Multistep Treatment of a Complex Electrolyte for Removal of Heavy Metal Ions and Recycling in Electrochemical Machining

Abstract During electrochemical machining (ECM) of metals, the electrolyte gets polluted by heavy metal ions and compounds. This creates crucial process control problems due to variation in electrical conductivity and is an environmental threat if the solution is discharged without treatment. In this study, an economical, simple multistep treatment system based on ion-exchange was developed to remove metal ions from the polluted electrolyte. We specifically looked at the electrolytic discharge from ECM of copper pieces, which is widely used in biomedical and electronic applications. Three different ion-exchange media were used: (1) a natural zeolite, (2) a special type of adsorbent quantitative filter paper, and (3) a polymer-based synthetic cation-holder resin (Lewatit TP 207) that works well with copper ions. Optimization studies for pH and contact time showed the following: (1) by using zeolite alone, and after 2 h of mixing, 43.2% of Cu2+ could be removed; (2) by using the filter paper alone, and after three times of filtration, 90% of Cu2+ could be removed; and (3) by using Lewatit TP 207 alone, 100% of Cu2+ could be removed. While Lewatit TP 207 allowed for 100% removal of Cu2+, its use alone is costly and troublesome due to constraints from service life and multistep regeneration and conditioning with strong acids and bases, respectively. The most simple and economical scheme for removal of Cu2+ and recycling the electrolyte for reuse was the three-step zeolite-filter-resin treatment system.

Recovery of uranium from carbonate solutions using Lewatit TP 107 resin

Uranium is extracted from ore bodies by leaching with either sulfuric acid or sodium carbonate/bicarbonate (alkaline) solutions. Alkaline leaching is usually preferred for ores with gangue compositions that would otherwise result in excessive acid consumption. After leaching, ion exchange is then commonly used to recover uranium from the liquor. Strong-base anion-exchange resins are generally used for both liquor types.In this work, a recently released high capacity strong-base anion-exchange resin resin (Lewatit TP 107) was examined for the extraction of uranium from alkaline leach liquor simulants. The effect of solution composition on uranium adsorption was studied, including pH, carbonate, sulfate, chloride and nitrate ion concentrations. The results were then used to develop a competitive ion exchange model. The elution of uranium by a variety of industrially relevant eluents was also examined, and the loading and elution data was benchmarked against a conventional resin.The results showed that uranium loading for TP 107 was two to three times greater than for the conventional resin, particularly at lower uranium tenors. However, the elution process was more difficult, requiring about twice the amount of eluent for a given resin volume. This suggests that TP 107 could be used for uranium recovery from alkaline liquors, and would be particularly attractive for lower grade deposits.

La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte XI: Cobalto(II)/H&lt;sup&gt;+&lt;/sup&gt;/Lewatit TP260

Este trabajo investiga sobre la eliminación de cobalto(II) presente en medios acuosos mediante la resina de cambio iónico Lewatit TP260. El sistema se estudia bajo distintas condiciones experimentales: velocidad de agitación (300-1400 min-1), temperatura (20-60 ºC), pH del medio acuoso (1-5), dosificacion de la resina (0.07-0.5 g·L-1) y fuerza iónica de la disolución acuosa. El metal se carga en la resina mediante una reacción de intercambio catiónica en un proceso endotérmico y espontáneo. Esta reacción de intercambio se define por un proceso de difusión en la disolución acuosa y el modelo cinético de pseudo-primer orden (20 ºC) y el modelo cinético de pseudo-segundo orden (60 ºC), asimismo los resultados experimentales se ajustan bien a la isoterma de Langmuir. Los resultados experimentales del sistema se han comparado con los obtenidos con otras resinas de intercambio cationico y también con nanotubos de carbono de pared multiple oxidados y sin oxidar. Se estudia la selectividad del sistema Co(II)-Lewatit TP260 con respecto a la presencia de otros cationes (disoluciones binarias Co-metal) en el medio acuoso). El cobalto(II) cargado en la resina se puede fluir con disoluciones ácidas (HCl o H2SO4).

Harmless treatment and selective recovery of acidic Cu(II)-Cr(VI) hybrid wastewater via coupled photo-reduction and ion exchange

Herein, we report a simple two-step method combining adsorption and photoreduction toward the effective removal, separation, and recovery of Cu(II) and Cr(VI) from their hybrid wastewater. A solid solution photocatalyst consisting of TiO2-ZrO2 was utilized to photoreduce Cr(VI) in the absence of a sacrificial agent. The Cr(VI) removal rate reached 95%, whereas Cu(II) was substantially retained in the solution. Conversely, a commercial cation exchange resin, Lewatit TP207, only adsorbed Cu(II) without any notable change in the Cr(VI) concentration. After combining these two selective removal processes, both Cu(II) and Cr(VI) in wastewater can be removed to reach the wastewater discharge standard regardless of the treatment sequence used. However, the most effective sequence was photocatalysis after ion exchange. The residual Cu(II) concentration was 0.06 mg/L and the total Cr concentration was 0.74 mg/L without Cr(VI). The Cu(II)/Cr(VI) separation efficiency was 11,949 with 99.17% Cu(II) and 96.29% Cr(VI) recovered. This work provides a promising referable process for hybrid heavy metal ion wastewater treatment.

Recovery of metals by ion exchange process using chelating resin and sodium dithionite

Chelating ion exchange resins can be used to recover metals from nickel laterite leach solution. The main problem is the high presence of iron. In pH above 2.00, iron precipitates and there is co-precipitation of copper and cobalt, which decreases recovery process efficiency. To solve this problem, a conversion of Fe(III) to Fe(II) can be the solution, where Fe(II) will precipitate just at pH 5.00. This reducing process can also increase metals recovery, where ferrous iron occupies less active sites on the resin than ferric iron. However, studies do not evaluate what happens to the resin under this situation. This work aimed to study the copper, nickel and cobalt recovery using chelating ion exchange resin Lewatit TP 207 and reducing process using sodium dithionite 1 mol.L−1. Sodium dithionite was used to convert Fe(III) to Fe(II). The effect of reducing agent on the resin was studied. Three different solutions where prepared to simulate the real nickel laterite leach solution. Batch experiments were performed to study the effect of pH to recover metals and to compare the results with and without the reducing agent. Results showed that metals adsorption increased when the ferric iron was converted to ferrous iron by reducing process. Chelating resin adsorbed more copper and also was selective for this metal at pH 2.50. Nickel and cobalt adsorption were higher at pH 3.50, but the resin was not selective for these metals under this pH. The order of selectivity of chelating resin changed when pH increased.

Selective removal of aluminum, nickel and chromium ions by polymeric resins and natural zeolite from anodic plating wastewater

ABSTRACT Aluminum industry has been well-known for producing enormous volume of wastewater in high concentration of varied heavy metals and toxic substances with wide variation in pH. In this study, selective removal of aluminum, nickel and chromium by polymeric resins (Amberlite IR120, Lewatit TP207) and natural zeolite from aluminum anodic plating process wastewater in varying aluminum concentrations (~10–200 mg/L), very low pH (3–4) and high conductivity (5090–8540 µS/cm) was evaluated. The wastewater was collected from a factory producing aluminum profiles (Kayseri, Turkey) where anodic oxidation plating is applied. The affinity of adsorbents towards to metals was in order aluminum > nickel > chromium. The kinetic results revealed that sorption of heavy metals onto adsorbent obeys pseudo-second-order model. The experimental data fitted the best to modified Freundlich isotherm. Aluminum uptake by adsorbents was feasible, exothermic and spontaneous by Amberlite IR120 and Lewatit TP207; however, the reaction was endothermic for zeolite.

Selective isolation of heavy metals from spent electronic waste solution by macroporous ion-exchange resins.

Electronic waste (e-waste) has become an urgent issue in digitally dependent world, owing to the unprecedented use of electronic devices and this has compelled the world to develop new techniques to recycle such wastes. In this work, one of problematic and high volume global waste stream, i.e., end-of-life printed circuit boards (PCBs), was examined for recycling. Using ion-exchange (adsorption/desorption) technique, heavy metals (Cu, Zn, Ni, and Pb), and Al were selectively recovered and separated. Three macroporous ion-exchange resins (Amberlite IRA 743, Lewatit TP 208, and Lewatit TP 260) were applied to extract, isolate and concentrate the heavy metals. The process factors (resin load, solution temperature and contact time) were investigated and kinetic behavior of adsorption was studied using three different models. Based on the process factors, the functionality and selectivity of the ion-exchange resins were discussed. A negligible amount of Ni and Zn adsorption on the surface of resin 743 indicates its high selectivity. This study also proves that selective isolation of hazardous elements such as Pb can be performed under specified sorption parameters. Also, the distribution of adsorbed cations throughout the resin beads was studied via elemental analysis. The distribution of Cu as the main element was not homogenous that signifies the higher practical capacity of the ion-exchanger. Finally, a stripping step was applied to modify the working media and to examine the reversibility and selectivity of the desorption process.