Resin Dowex Research Articles

Molybdenum Recovery from the Copper Hydrometallurgical Extraction Route with High Content of Chloride Ions Using the Ion Exchange Technique

This manuscript describes molybdenum recovery from copper Pregnant Leaching Solutions (PLSs) in the copper oxide mining industry with high contents of chloride ions. This product was recovered from the copper leaching pond solutions of the Chilean National Copper Mining Corporation (CODELCO) using the ion exchange process. This process recovered molybdenum from initial Mo concentrations of 50 mg/L using two different anion−exchange resins. The first experiments, with 1 g/L Cl−, achieved recovery yields of 90% and molybdenum concentrates as CaMoO4. However, the process was permanently halted because of the early saturation of the ion exchange resins given by high chloride concentrations (10 g/L Cl−) of the original copper PLS and the significant reagent consumption given by the low adsorption capacity. Static studies were developed to determine the adsorption isotherms, followed by continuous molybdenum recovery tests. The Langmuir adsorption parameters were determined as a function of the chloride concentration, giving absorption capacities from 180 to 250 mg Mo/gram of resin and recoveries from 63% to 90%. The breakthrough values for the DOWEX and Lewatit resins for chloride contents of 10 g/L were 180 and 245 BV, respectively, while for 1 g/L, these values were 620 and 890 BV. This allowed obtaining elution solutions of 890 mg Mo/L for the DOWEX resin and 1000 mg Mo/L for the Lewatit resin.

Determination of parameters and kinetic evaluation for chromium (VI) removal using four resins

This research aimed to identify optimal studied variables for chromium (VI) removal using four resins (IRA 96, IRA 400, DOWEX 1x8, and LEWATIT). A 1,5-diphenylcarbazide method was used for the quantification of chromium (VI). A factorial design with triple replication at the center point was used to evaluate pH, resin dose (g/100 mL), and initial chromium (VI) concentration. The optimal values for the four resins were a pH of 3, a resin concentration of 0.15 g/100 mL of solution, and an initial concentration of 10 mg/L of chromium. Then, an ANOVA study was done to compare the resins results using a p-value <0.05. The DOWEX resin presented the highest removal percentage (98.39%) for a reaction period of 45 minutes, with an exponential model that fits a pseudo-first-order kinetics with a coefficient of determination equal to 0.967.

Resin screening and process optimization for erythritol mother liquor chromatographic separation

In order to improve the utilization value of the erythritol mother liquor, the separation and purification of the erythritol mother liquor was selected in this study. The selected chromatographic separation programme for erythritol crystallizing mother liquor is as follows: Firstly, erythritol is resolved from mannitol and arabitol with DTF-01Ca (Suqing Group) resin and then mannitol is resolved from arabitol with 99Ca/320 (Dowex) resin. At the same time, the chromatographic conditions of the DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins were optimized, resulting in an optimal separation temperature and mobile phase flow rate of 70 °C, 10 ml/min. On this basis, a single-column chromatographic model was used to calculate the TD model parameter ( N ) and the mass transfer coefficient ( k m ) of the separation of erythritol mother liquor by DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins. The adsorption isotherms, TD model parameter ( N ) and the mass transfer coefficient ( k m ) provides data references for the design and operation of the simulated moving beds (SMB) separation system for the industrial-scale separation of erythritol crystallizing mother liquor.

Environmentally safe technology of waste processing of galvanic production

It is known that waste is difficult to purify using existing reagent methods to the standards of the MPC. In addition, the formed sediments contain poorly soluble hydroxy compounds of heavy metals and gypsum, which makes it impossible to dispose of iron- and copper-containing electroplating sludges. The purpose of the study was to study the possibility of ion exchange separate and simultaneous extraction of iron and copper ions from acidic solutions of pickling and copper plating in galvanic production to obtain ferrites. In the course of research, the highly acidic cation exchange resin Dowex HCR S/S in the H+ form was chosen as the cationite. The choice of a strongly acidic cationite is justified, based on the fact that cationites of this type are able to easily lose hydrogen ions due to their displacement from the cationite matrix by other cations of the solution. The sorption processes of iron (II) and copper (II) ions were carried out under dynamic conditions. In the course of experimental studies, it was shown that with an increase in the concentration of sulfuric acid, the full exchangeable dynamic capacity of the cationite significantly decreases both during the sorption of iron ions and during the sorption of copper ions. For iron-containing solutions, full dynamic exchange capacity decreases from 1.39 g-eq/dm3 in the absence of H2SO4 in the initial solution and decreases to 0.3-0.46 g-eq/dm3 at a concentration of sulfuric acid at the level of 1-3 g/dm3. An increase in the concentration of iron (II) ions leads to a significant increase in full dynamic exchange capacity, even with a concentration of sulfuric acid of 8 - 13 g/dm3, full dynamic exchange capacity was at the level of 1.35 g-eq/dm3, which corresponds to the level of sorption of diluted solutions even in the absence of acid. However, the total concentration shows that the efficiency of sorption of metals from acidic solutions remains quite high and increases with the increase of the initial total content of sorbed ions. The main indicator used when choosing an ion exchange method is the possibility of effective regeneration of the cation exchange material. When using 5% solution of sulfuric acid already at the specific consumption of the regeneration solution, it was possible to achieve a degree of regeneration at the level of 95-98%, and when using 10% solution, the degree of regeneration reached 100%. According to the developed technological scheme, regeneration solutions are processed by precipitation into magnetite in a ferritizer reactor. To remove iron ions from concentrated iron-containing regeneration solutions by the ferrite method in order to obtain ferrite particles (magnetite) with maximum magnetic properties, a mixture of Fe (II) and Fe (III) sulfates was used with their concentration ratio K = [Fe2+]/[Fe3+] = 0.5, as a stable relationship between magnetic properties and sediment volume was noted. At maximum magnetic properties, the sediment volume is minimal, and vice versa. Obtaining highly dispersed magnetic particles from a mixture of ferric and ferric sulfates by precipitating them with 10% NaOH solution during heating allows to significantly reduce the duration of the process, simplify it and increase the productivity of the equipment. To obtain magnetic particles of copper ferrites from regeneration solutions by precipitation with alkali at normal temperatures, the concentration ratio K1 = [Fe2+]/[Cu2+] = 3.15-7.76 should be maintained. With an increase in the concentration of Cu2+ ions, there is an increase in the period of crystallization of the obtained sediments and their acquisition of magnetic properties. The formed ferrite material can be used for environmental purposes as a valuable raw material for carbon monoxide neutralization catalysts, as part of alkaline cement for concrete products, or sent for safe disposal. The obtained results on the application of ion-exchange extraction of iron and copper ions from acidic solutions of galvanic production are expedient as the first stage of complex ecologically safe processing of galvanic wastes with the production of ferritic materials for industrial use.

ADSORPTION OF IRON(III) IONS FROM SULFURIC ACID SOLUTIONS BY DOWEX G-26 RESIN (Н)

The adsorption of iron (III) from sulfuric acid solutions on a strongly acidic cation-exchange resin Dowex G-26 (H) has been studied. The factors influencing the adsorption of iron (III) have been investigated: solution pH, contact duration, adsorbent dose, initial concentration of iron (III) in solution. The obtained results show that Dowex G-26 (H) resin has a high exchange capacity for iron (III) ions from sulfuric acid solutions. Complete adsorption of iron (III) was achieved at pH2 (99%). Based on the experimental results, Langmuir and Freindlich adsorption isotherms have been constructed. Both isotherms fully describe the adsorption of iron(III) by the Dowex G-26 adsorbent. However, a comparison of the Langmuir correlation coefficient (R2=0.9098) with respect to Freundlich (R2=0.9915) shows that the Freundlich isotherm provides a better fit than the Langmuir isotherm. Quantitative and quantitative sorption properties of Dowex G-26 (H) relative to iron (III) have been investigated using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The maximum adsorption capacity (qm) for iron (III) was 166 mg/g at 250C. It has been shown that Dowex G-26(H) can be recommended as an adsorbent for sorption of Fe(III) from acidic solutions

Sorption and leaching of lithium ions from aqueous nitrate/ascorbate solution using Dowex 50WX8 sodium form

ABSTRACT In this work, Green and sustainable sorption method for Li(I) from nitrate medium using a solid functionalised Na+ form of Dowex 50WX8 resin was developed. Scanning electron microscope (SEM), Fourier transform infrared (FT-IR), and energy-dispersive X-ray (EDX) techniques were used for characterisations of Dowex resin before and after the loading of Li ions. The batch technique describes the effects of the different parameters affecting the sorption process was carried out. The batch experiments were studied using 100 mg/L Li(I) at the selected sorption conditions (shaking time = 30 min, adsorbent weight = 0.125 g, temperature= 25°C, and pH = 1) which give sorption efficiency = 60%. The experimental maximum sorption capacity of Dowex 50WX8-Na+ after one sorption cycle was found to be 15 mg/g . Thermodynamic studies indicated that the sorption of the Li(I) on Dowex 50WX8-Na+ resin is physical and exothermic adsorption with spontaneous nature. The maximum desorption efficiency of 85% and 70% was achieved with 1.0 M phosphoric acid and oxalic acid, respectively. An industrial application for green recycling and recovery of Li(I) from spent Li-ion batteries (LIBs) through its leaching with ascorbic acid (1.25 M) and H2O2 (10%) was performed. Lithium ions were selectively recovered (uptake %= 96%) from the spent Li-ions batteries leachate which contains associated metal ions (Co, Ni, and Mn) with Dowex 50Wx8-Na+ sorbent. A flow sheet that presents the performance of industrial method developed for the recycling and separation of Li(I) from (LIBs) under optimum sorption conditions is also provided.

Ion exchange behavior of astatine and bismuth

Astatine sorption by ion exchange resins from nitric acid media.

Glycidyl Cinnamate: Copolymerization with Glycidyl Ethers, In‐Situ NMR Kinetics, and Photocrosslinking

AbstractThe copolymerization of glycidyl cinnamate (GC) as a hitherto non‐polymerizable, photoreactive epoxide structure to aliphatic polyether copolymers is described, using the monomer‐activated epoxide ring‐opening polymerization (MAROP). Ethoxyethyl glycidyl ether (EEGE) and GC are copolymerized employing triisobutylaluminum (i‐Bu3Al) as a catalyst and tetraoctylammonium bromide (NOctBr4) as an initiator. The amount of GC varies from 3 mol% to 100 mol%, which results in apparent molecular weights in the range of 2600 to 4600 g mol−1and dispersities (Đ)below 1.34. Studies of the microstructure by in‐situ1H NMR kinetics indicate a gradient‐like distribution of EEGE and GC (reactivity ratios:rEEGE= 0.28;rGC= 3.6), applying the ideal copolymerization model for evaluation. A tentative explanation relies on differing bond lengths in the respective epoxide rings, as suggested by density functional theory (DFT) calculations. Mild and selective cleavage of the acetal protecting groups of EEGE is achieved using the acidic ionic resin Dowex, leaving the GC ester bonds intact (Mn = 1900–3700 g mol−1,Đ <1.34). Thermal properties of the copolymers and the PGC homopolymer are investigated by differential scanning calorimetry (DSC). The crosslinking of P(G‐co‐GC) copolymers by UV irradiation allows hydrogel formation, which is confirmed by IR spectroscopy.

Adsorption of Cu(II) ions from aqueous solutions using ion exchange resins with different functional groups

AbstractThe extraction of heavy metals from industrial effluents using efficient adsorbents is crucial for wastewater treatment and beneficial for metal recycling. In this study, the removal of Cu(II) from an acidic solution by commercial resins Dowex G‐26 and Puromet™ MTS9570 was investigated. The influences of contact time, solution concentration, pH, temperature, and a resin dosage on the adsorption process were studied with batch technique. The optimum adsorption conditions were obtained at a concentration of 1100 mg/L Cu, contact time of 30 min, pH 3.5, and resin dosage of 0.025 g/ml for the removal of 99.9% and 90% of copper ions by G‐26 and MTS9570, respectively. The experimental data of copper adsorption were analyzed using the Langmuir, Freundlich, and Temkin isotherm models. The highest metal uptakes of 41.67 and 37.70 mg/g were observed for Dowex G‐26 and MTS9570, respectively. It was found that both resins had higher adsorption capacities than the substances reported in the literature. The adsorption kinetic studies showed that the copper adsorption process could be better described by the pseudo‐second order model. Adsorption occurs spontaneously under endothermic conditions, which indicates the endothermic nature of the process.

Lithium-Ion Battery Recycling: Metal Recovery from Electrolyte and Cathode Materials by Electrodialysis

The potential of electrodialysis to recycle spent lithium-ion batteries was assessed by investigating the recovery of lithium(I) from a synthetic solution representative of the aqueous effluent generated by shredding spent lithium-ion batteries underwater. Likewise, electrodialysis was tested for the selective recovery of lithium(I) towards cobalt(II), nickel(II) and manganese(II) from a synthetic solution representative of the leaching liquor of cathode materials. NMR spectroscopy showed that the implementation of electrodialysis to extract lithium from the aqueous effluent produced during battery shredding underwater should take into account the presence of HF generated by PF6− hydrolysis. In particular, it seems relevant to perform shredding under calcium chloride solution in order to precipitate fluoride and reduce HF generation. This work also showed that electrodialysis is an interesting technology for selectively recovering lithium from the leach solution of spent cathode materials, providing that divalent cations were previously removed to avoid metal precipitation inside the electrodialysis membranes. After removing cobalt(II) and nickel(II) at pH 2.8 and manganese(II) partially at pH 5.5 by using the ion exchange resin Dowex M4195, it is possible to extract and selectively concentrate lithium by electrodialysis without coextracting manganese(II) by using a lithium-selective membrane (faradic efficiency of 57.6%, permselectivity for lithium towards manganese of 6.9). Finally, a hybrid flowsheet implementing mineral processing and hydrometallurgy, including electrodialysis, ion exchange and crystallization stages, was proposed based on these results to reduce effluent generation and produce metal salts from spent lithium-ion battery.

Dehydration of levoglucosan to levoglucosenone over solid acid catalysts. Tuning the product distribution by changing the acid properties of the catalysts

The effect of the catalytic properties of various types of solid acids, including oxides (ZrO2, SOX/ZrO2, WOX/ZrO2, Nb2O5, NbOPO4, Al2O3, TiO2), silica–aluminas (ZSM5 and USY zeolites) and acidic ion-exchange resins (Amberlyst-70 and Dowex 50wx8) were investigated for liquid-phase levoglucosan (LGA) conversion. H2SO4 was also evaluated as a reference catalyst. The concentration of both Brønsted and Lewis acid sites in the catalysts was measured by FTIR of adsorbed pyridine and titration with NaOH. The catalysts were tested under different reaction conditions (110–170 °C and 30–60 bar of N2) for 1 h using tetrahydrofuran (THF) as solvent. The product distribution obtained from the LGA conversion can be tuned depending on the type of acid site of the catalyst or the reaction conditions used. Catalysts containing only Bronsted acid sites were selective to LA while those with both Bronsted and Lewis acid sites favored the formation of 5-hydroxymethylfurfural (HMF). LGO was mainly produced by the homogeneous catalyst. The USY and HZM5 (SiO2/Al2O3 ratio of 23) promoted the production of HMF and glucose, respectively. A reaction mechanism was proposed taking into account the acid properties of the catalysts. The reactions of dehydration of LGA to LGO or hydration of glucose requires Brønsted acid sites. Catalysts with only Lewis acid sites produced only humins. For the catalysts containing both Brønsted and Lewis acid sites, LGA is mainly hydrated to glucose on the Bronsted acid sites. Then, glucose is preferentially isomerized to fructose on the Lewis acid sites, followed by its dehydration to HMF. The low LA formation shows that the hydration of HMF to LA requires a higher concentration of Brønsted acid sites.

The removal of toxic metals from liquid effluents by ion exchange resins. Part XVII: Arsenic(V)/H+/Dowex 1x8

The performance of anionic exchange resin Dowex 1x8 in the removal of arsenic(V) from aqueous solutions was investigated. Batch experimentation was carried out under different variables, including, the stirring speed applied on the system, the pH of the aqueous solution, resin dosage and temperature. Due to the characteristic speciation of arsenic(V) in aqueous phases, the removal of this element from the solution is negligible at highly acidic or alkaline pH values, but it is possible at the aqueous pH range of 4-9, thus, both HAsO42- and H2AsO4- species are loaded onto the resin. At the above pH range, arsenic(V) uptake is exothermic. Different models are fitted to the experimental values in order to gain knowledge about this ion exchange system: rate law, kinetics and solute loading onto the resin. This loading is compared against the yielded using non-functionalized multiwalled carbon nanotubes. The elution step is investigated using acidic solutions (HCl medium) as eluent, from the eluted solutions, arsenic(V) can be efficiently stabilized as ferric or calcium arsenates.

Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate Using Strongly Basic Anion-Exchange Styrene–Divinylbenzene Dowex Resins

Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate Using Strongly Basic Anion-Exchange Styrene–Divinylbenzene Dowex Resins

Evaluating Radioactive Analogs of Doxorubicin to Quantify ChemoFilter Binding and Whole-Body Positron Emission Tomography/Magnetic Resonance Imaging for Drug Biodistribution

PurposeTo evaluate radiolabeled doxorubicin (Dox) analogs as tracers of baseline Dox biodistribution in vivo during hepatic intra-arterial chemotherapy and to assess the efficacy of ChemoFilter devices to bind Dox in vitro. Materials and MethodsIn an in vitro static experiment, [fluorine-18]N-succinimidyl 4-fluorobenzoate ([18F]SFB) and [fluorine-18]fluorobenzoyl-doxorubicin ([18F]FB-Dox) were added to a beaker containing a filter material (Dowex cation exchange resin, single-stranded DNA (ssDNA) resin, or sulfonated polymer coated mesh). In an in vitro flow model, [18F]FB-Dox was added into a Dox solution in phosphate-buffered saline, and the solution flowed via a syringe column containing the filter materials. In an in vitro flow experiment, using micro-positron emission tomography (PET), images were taken as [18F]SFB and [18F]FB-Dox moved through a phantom. For in vivo biodistribution testing, a catheter was placed into the common hepatic artery of a swine, and [18F]FB-Dox was infused over 30 seconds. A 10-minute dynamic image and three 20-minute static images were acquired using 3T PET/MR imaging. ResultsIn the in vitro static experiment, [18F]FB-Dox demonstrated 76.7%, 88.0%, and 52.4% binding to the Dowex resin, ssDNA resin, and coated mesh, respectively. In the in vitro flow model, the first-pass binding of [18F]FB-Dox to the Dowex resin, ssDNA resin, and coated mesh was 76.7%, 74.2%, and 76.2%, respectively, and the total bound fraction was 80.9%, 84.6%, and 79.9%, respectively. In the in vitro flow experiment using micro-PET, the phantom demonstrated a greater amount of [18F]FB-Dox bound to both filter cartridges than of the control [18F]SFB. In in vivo biodistribution testing, the first 10 minutes depicted [18F]FB-Dox moving through the right upper quadrant of the abdomen. A region-of-interest analysis showed that the relative amount increased by 2.97 times in the gallbladder and 1.08 times in the kidney. The amount decreased by 0.74 times in the brain and 0.57 times in the heart. Conclusions[18F]FB-Dox can be used to assess Dox binding to ChemoFilters as well as in vivo biodistribution. This sets the stage for the evaluation of ChemoFilter effectiveness in reducing systemic toxicity from intra-arterial chemotherapy.

Adsorption and possibility of separation of heavy metal cations by strong cation exchange resin

This work is devoted to the study of the adsorption of strontium, yttrium, and zirconium ions by the strong acid cation exchange resin Dowex HCR-s/s. The adsorption of strontium, yttrium, and zirconium ions in batch and dynamic conditions from individual solutions of the studied elements, as well as from their mixture, was studied. It was shown that the dependences of the adsorption of strontium, yttrium, and zirconium ions on agitation time fit well with the pseudo-first-order and Elovich equations. Equilibrium adsorption of all three cations can be described with Langmuir's theory. Column adsorption has shown that Dowex HCR-s/s adsorb all three investigated cations from the acidic medium. The inductively coupled plasma mass spectrometry (ICP-MS) proves that separation of these cations using Dowex HCR-s/s is possible only in highly dilute solutions at a concentration of 10 ng/ml of each element. The basis of separation will be a higher rate of adsorption of tetravalent zirconium, compared with strontium and yttrium. As the concentration of the investigated elements increases to 100 ng/ml, all three cations are adsorbed by the resin in equal amounts and can be separated only using special eluents, such as Ca-EDTA.

Rhenium Distribution and Behavior in the Salinity Gradient of a Highly Stratified Estuary and Pristine Riverine Waters (The Krka River, Croatia).

The abundance and distribution of dissolved Re (DRe) were determined in the freshwater part of the Krka River (Croatia), which drains a karst landscape, and in the salinity gradient of its highly stratified estuary. Due to the low DRe concentration, a batch procedure consisting of a pre-concentration step using an anion exchange resin (Dowex) and analysis of DRe in 8M HNO3 eluate using high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS) was applied. Due to potentially inconsistent recoveries, which ranged from 60 to 87%, quantification was performed using the isotope dilution technique (ID). DRe concentrations in the Krka River increased downstream, from 6.2pM at the spring site to 11.9pM upstream of the estuary region. Weathering of the surrounding carbonate lithology is assumed to be the source of the natural Re. Two specific anomalies were registered: a strong increase in DRe concentration due to anthropogenic input near the town of Knin (27.5pM) and a decrease at a downstream site caused by subsurface input of freshwater from the Zrmanja River, resulting in a relatively low DRe concentration (8.5pM). In the estuarine region, a near-conservative behavior of DRe was found in the salinity gradient of the upper surface layer, with DRe concentrations ranging from 18 to 38pM. Anthropogenic input was suspected within the estuarine segment near the urban area, causing a small positive deviation from the conservative line. In the bottom seawater layer, a minor decrease in DRe concentration in the most upstream estuarine regions was apparent, implying weak scavenging of Re.

The Development of a rapid method for Plutonium separation by extraction chromatography and its application for environmental samples

This research aims to develop a rapid method of plutonium analysis from sediment samples using the extraction chromatography method with TRU resin. This approach will be compared with the anion exchange method with DOWEX resin previously conducted in the BATAN radioecology laboratory. Plutonium measurements was carried out using an alpha spectrometer with a PIPS detector after the separation processes. The results showed that recovery using extraction chromatography followed by the microprecipitation method resulted in an average recovery of 71.22 percent, compared to anion exchange using the electrodeposition method, which obtained about 58.89 percent. Since a combination of chromatographic extraction with electro-deposition, the recovery is still low, about 27.56 percent. The chromatographic extraction method with microprecipitation method to sediment samples from the coast of Merak resulted in an average activity of 0.14 Bq/kg dry. The activities obtained are comparable with the previous data from the Merak coastal sediment study. The advantages of using the extraction chromatography method compare to using the anion exchange method to separate plutonium from sediment samples are the shorter separation time and the less acid waste produced. Another advantage is that it is more selective to separate plutonium from other actinides. This approach is very suitable for emergency preparedness when there is an emergency response.

Impactful modulation of micro-structures of acid-resistant picolylamine-based chelate resins for efficient separation of heavy metal cations from strongly acidic media

• PMAA-PD showed better separation ability for Ni(II) versus Co(II) than M4195. • PMAD-PD could adsorb Ni(II) (0.920 mmol/g) and Co(II) (0.605 mmol/g) at pH 1.0. • The reagent costs of PMAA-PD and PMAD-PD were only 15%-20% of that of M4195. • Cu(II) owned much more stable binding to picolylamine-based resins than other HMCs. • Inorganic salts promoted the HMCs adsorption by weakening electrostatic repulsion. The efficient separation of heavy metal cations (HMCs) from strongly acidic media (pH < 2.5) by adsorption is admittedly challengeable due to the obvious protonation. Aiming at this problem, two acid-resistant picolylamine-based chelate resins PMAA-PD and PMAD-PD with different micro-structures were prepared based on the intermediate modification with ethylenediamine or tetraethylenepentamine (TEPA). The reagent costs for preparing PMAA-PD and PMAD-PD were estimated to be only 15%-20% of that for the same-type commercial resin Dowex M4195 (M4195), but their maximum adsorption capacities of Ni(II) (1.535 and 1.713 mmol/g) at pH 2.0 exceeded that of M4195 by 37.54% and 53.49%, respectively. The combination of amide oxygen and bis-picolylamine functionality in PMAA-PD was verified to form more stable binding to Ni(II) relative to the single bis-picolylamine functionality in M4195, resulting in its separation factor α Ni(II)/Co(II) of 50.9 being 79.31% higher than that of M4195 and making it more adequate to separate Ni(II) from acidic cobalt-rich liquid to produce high-purity cobalt (>99.99%). Additionally, PMAD-PD showed the better acid resistance and a versatile decontamination capacity toward Cu(II), Ni(II), Co(II), Zn(II), Cd(II), Fe(II) and Fe(III) for complex strongly acidic wastewater, as its special micro-structure characterized by plentiful small-size pores (<4 nm) and long TEPA skeleton caused abundant synergetic chelation. Moreover, coexisting inorganic salts promoted the HMCs adsorption onto both PMAA-PD and PMAD-PD by weakening electrostatic repulsion. Therefore, the self-synthesized picolylamine-based chelate resins are promising to efficiently separate HMCs from specific acidic industrial media and thus achieve the purification or decontamination.

Increasing large-scale feasibility of two-phase olive-oil washing wastewater treatment and phenolic fraction recovery with novel ion exchange resins

The present investigation was focused on improving the feasibility of large-scale application of a ‘green’ procedure to recover total antioxidant compounds (TACs) by solid phase extraction from the liquid residues of oleic industry (two-phase olive oil washing wastewaters, OOWW). To this aim, the use of ion exchange resins Dowex 21 K XLT® strong base and Dowex 66® weak base was examined. Adsorption capacity equal to 146.12 mg TACsadsorbed/gresin upon 114 gresin/LOOWW for the weak-base resin and 117.29 mg TACsadsorbed/gresin for 114 gresin/LOOWW for the strong-base resin was successfully attained. Thus, it was possible to recover up to 83.3% TACs with the weak-base resin in contrast to 60.8% with the strong-base one. Also, 55.8% vs. 53.7% COD removal was ensured. The process could be driven with raw OOWW, taken directly at the conditions at the outlet of vertical centrifuges, since narrow improvement with T and pH modifications was found. Moreover, significant reduction in phenols concentration would prevent biomass inhibition of further biological treatments, or even permit partial discharge on land. On the other hand, the high added-value concentrated pool of antioxidant compounds would be key to render the reclamation of this effluent feasible at industrial scale.

Synthesis of Dowex functionalised half-sandwich Ru (II) (η6-p-cymene) complex as effective and selective hydrogenation of furfural to levulinic acid

The ruthenium(II) complex [(η6-p-cymene)Ru(Cl)(8-amino quinoline)] and [η6-p-cymene)Ru(OH2)(8-amino quinoline)] were synthesised, charactrised, and used to prepare novel ruthenium(II) based Dowex resin polymer [(η6-p-cymene)Ru(Cl / or OH2)(8-amino quinoline)]@Dowex. The ruthenium(II) comlex based Dowex catalyst is synthesisedby treatment of [(η6-p-cymene)Ru(Cl)(8-amino quinoline)] or [η6-p-cymene)Ru(OH2)(8-amino quinoline)] with Dowex@Na via ion exchange synthesis, in the presence of DCM as a solvent forming [(η6-p-cymene)Ru(Cl / OH2)(8-amino quinoline)]@Dowex, respectively. The developed Dowex polymer were caractrised by IR spectroscopy, ICP analysis, and 13C Solid-State NMR. The ICP proved the presence of Ru in the polymer resien with 63 and 61 wt% respectively. The catalytic transfer hydrogenation of furfural over both Ru(II) comlex based Dowex catalyst were investigated with formic acid as the hydrogen donor and water as the solvent at 80 oC after 19 h. The [(η6-p-cymene)RuCl (8-amino quinoline)]@Dowex and [(η6-p-cymene)RuOH2(8-amino quinoline)]@Dowex catalysts were shown to exhibit high activity in the transfer hydrogenation of furfural to form a sole levulinic acid (Lv) giving good conversion and excellent selectivity under mild reaction conditions. The [(η6-p-cymene)RuOH2(8-amino quinoline)]@Dowex catalyst showed high stability and reactivity in four catalyst recycling runs, which presents a completed selectivity of levulinic acid and enhancement of yield to 66%. Therefore, recyclability and leaching tests confirmed [η6-p-cymene)Ru(OH2)(8-amino quinoline)] complex to function as a heterogeneous catalyst which could be reused for at least four consecutive reaction runs without significant loss of catalytic activity.