Commercial Ion Exchange Resin Research Articles

Removal of sodium and chloride ions from aqueous solutions using fique fibers (Furcraea spp.).

Fique fibers obtained from the leaves of Furcraea spp., a highly abundant plant in the mountains of South America, may offer an alternative as biosorbents in desalination processes as they exhibit high removal capacities (13.26 meq/g for chloride ions and 15.52 meq/g for sodium ions) up to four times higher than exchange capacities commonly observed in synthetic resins. The ion removal capacity of the fibers was also found to be a function of the pH of the solution with the maximum removal of ions obtained at pH 8. Unlike most commercial ion exchange resins, our results suggest that fique fibers allow simultaneous removal of chloride and sodium ions.

Ruthenium Recovery from Acetic Acid Waste Solution by Using PEI-Coated Biomass-Chitosan Composite Fiber

Polyethylenimine (PEI)-coated biomass-chitosan composite fiber (PBCF) was fabricated to recover Ru from acetic acid waste solution. The present work aimed to understand the effects of molecular weight of chitosan and drying method on stability and sorption performance of the PBCF. For this, the PBCF was prepared by extruding the mixed solutions of chitosan and Corynebacteriumglutamicum to form the composite fibers which were modified with ionic polymer, PEI. The degree of swelling of PBCFs prepared by hot-air, natural, and freeze drying methods were 1.25, 1.34, and 1.07 %, respectively, indicating that the freeze-drying method was the best. Batch biosorption studies showed that the maximum Ru uptake could be achieved with PBCF prepared with medium molecular weight chitosan, and could reach 34.1 mg/g, which was 7.9 times higher than that of the commercial ion exchange resin, LEWATIT® MonoPlus M 500 (4.3 mg/g). Therefore, PBCF can be considered as an alternative sorbent to synthetic resin for recovery of Ru form industrial acetic acid waste solution.

Synthetic Middle-Distillate-Range Hydrocarbons via Catalytic Dimerization of Branched C6–C8 Olefins Derived from Renewable Dimethyl Ether

2,3,3-Trimethyl-1-butene (triptene) and other branched C6–C8 olefins, having structures characteristic of the products from the low-temperature acid-catalyzed homologation of dimethyl ether (DME), were converted to distillate-range hydrocarbons (C10–C20) with high selectivity via dimerization over a commercial ion-exchange acidic resin (Amberlyst-35) under liquid-phase stirred-batch conditions operating at ambient pressure. Triptene conversion and dimer (2,2,3,5,5,6,6-heptamethyl-3-heptene) production were monitored with time at different temperatures (60, 80, and 100 °C). The dimer production rate increased with increasing temperature; however, dimer concentration decreased with increasing temperature due to competing side reactions. Dimerization, as compared to cracking, isomerization, and oligomerization, was the dominant reaction pathway during the first hours of reaction at all temperatures. Dimerization at 100 °C achieved a conversion of 35% and a molar selectivity to the desired dimer of 71% in 2 h...

Carboxymethyl cellulose fiber as a fast binding and biodegradable adsorbent of heavy metals

In this study, a fast kinetic sorbent, epichlorohydrin cross-linked carboxymethyl cellulose fiber (ECMCF), was developed by using a simple synthetic method. SEM images showed that the ECMCF has a thin fibrous shape (20–90 µm of diameter) with a rough and porous surface, which is beneficial for the purpose of sorption. Cadmium metal ion (Cd(II)) was chosen as a model divalent heavy metal and the sorption performance of ECMCF was evaluated by batch and column experiments. The result of pH edge revealed that pH 6.0 was the best condition for Cd(II) sorption. The maximum uptake of Cd(II) by ECMCF was 150.60 ± 10.47 mg/g, which was comparable and higher than previously reported sorbents. Batch kinetic study showed that the ECMCF had a fast binding rate of Cd(II) within 2 min. Even in the column study, the ECMCF had a better breakthrough curve than two typical commercial ion exchange resins, Amberlite IRC 86 and Amberlite IR 120H, which were used as comparative sorbents.

A sustainable cationic chitosan/E. coli fiber biosorbent for Pt(IV) removal and recovery in batch and column systems

In this study, the cationic bacterial biosorbent, poly(allylamine hydrochloride) (PAA/HCl)-modified Escherichia coli, was successfully immobilized as a chitosan fiber, which was proved to be a sustainable biosorbent for platinum removal and recovery from aqueous solutions in batch and column systems. Compared to the commercial ion exchange resins, PAA/HCl-modified E. coli chitosan fiber showed a quite good performance for Pt(IV) removal. Two-parameter (Langmuir and Freundlich) and three-parameter (Sips and Redlich–Peterson) models were employed to describe the batch isotherm experimental data. Among these four models, the Redlich–Peterson model fit best, with higher coefficient of determination, chi-square and average percentage error values. Thermodynamic parameters (ΔG0<0 and ΔH0>0) showed the spontaneity and endothermic nature of biosorption process. The kinetics of Pt(IV) biosorption with different initial concentrations were better fit by the pseudo-second-order model, with higher coefficient of determinations and more closely predicted qe values. An acidified 0.005M thiourea was used to regenerate platinum from exhausted biosorbent maintaining desorption efficiencies over 90.2% until five cycles. In the column studies, the breakthrough curve showed a typical S-shaped curve, with breakthrough and exhaustion times appearing at 36.0h and 52.5h, respectively, which was opened up a possibility of column regeneration.

Novel membrane-supported hydrogel for removal of heavy metals

Polyethersulfone membranes with integrated negatively-charged hydrogel of crosslinked poly(acrylamido-2-methylpropane sulfonic acid) were prepared by a combination of a liquid phase inversion process with photopolymerization and crosslinking of functional monomers included in the casting solution. A designed experiment was conducted to select the optimal composition for preparing membranes with a sufficient degree of swelling and ion exchange capacity. Scanning electron microscopy images revealed an ultrafine hybrid structure with an interconnected network of submicron particles embedded within the microporous polyethersulfone support. An intramembrane diffusion model was used to describe kinetics of heavy metal sorption by these hydrogels and the calculated apparent diffusion coefficients were 2–3 times larger than in commercial ion-exchange resins. Equilibrium sorption of heavy metals was described using a semi-empirical Langmuir model.

A mild route to solid-supported rhodium nanoparticle catalysts and their application to the selective hydrogenation reaction of substituted arenes

A clean route is described for the preparation of 1.3% (w/w) supported rhodium nanoparticle (3.0 ± 0.7 nm) catalysts onto commercial ion-exchange resins.

Study on the removal of dissolved organic matters in the raw water by a new magnetic anion-exchange resin

The removal of dissolved organic matters (DOM) in the raw water of Tongyu River using a new magnetic anion-exchange resin (NDMP) was investigated. NDMP was more effective than a commercial magnetic ion-exchange resin (MIEX) for the purification of drinking water. NDMP can eliminate 49% of dissolved organic carbon (DOC) and 86% of UV absorbance at 254nm (UV254) in the raw water within 30 min. During multiple-loading jar tests, DOC of the effluent was 2.1 mg/L at 100 BV and increased to 3.0 mg/L after the loading of 1,200 BV by NDMP treatment. The saturated resin was renewed after regeneration with sodium chloride. NDMP displayed high removal ability for both hydrophobic acid (HPO) and transphilic acid (TPI) compared to MIEX resin, whereas the removal rate of hydrophilic (HPI) was relatively low. The removal rates of HPO, TPI, and HPI in the raw water at the NDMP amount of 10 mL/L were 62, 65, and 24%, respectively. Therefore, the NDMP resin can be used in the purification of drinking water at high DOC level.

Selection of Ion Exchange Resins for Tungsten and Molybdenum Separation

A solution containing tungsten and molybdenum was acidified using hydrochloric acid, and the ability of several commercial ion exchange resins to separate tungsten and molybdenum was evaluated. The results from the acidification test indicate that when the pH of the solution is adjusted to 7.0, WO42- is polymerized into HW6O215-, while MoO42- is not. The test results of resins selection show that the D213 resin and the D308 resin are superior to other resins in separating low concentrations of tungsten and molybdenum, whereas the D201 resin and the D309 resin are suitable for separating high concentrations of tungsten and molybdenum. The results from the column test indicate that weak-base anion exchange resins are better than strong-base anion exchange resins for both low and high concentrations of tungsten and molybdenum.

Reaction Kinetics and Thermodynamic Equilibrium for Butyl Acrylate Synthesis from n-Butanol and Acrylic Acid

The esterification reaction of n-butanol with acrylic acid in the presence of a commercial ion-exchange resin, Amberlyst 15-wet, was carried out in a batch reactor. The reactions were performed at different temperatures (50 to 90 °C), different n-butanol/acrylic acid molar ratios (2 and 3), and different catalyst amounts (1 wt % to 3.5 wt %). Different reaction rate expressions were evaluated. A simplified Langmuir–Hinshelwood–Hougen–Watson kinetic model was found to be the best model to describe the experimental results. This model is given by the following expression: r = Kc·((a1·a2 – (a3·a4)/Keq)/(1 + K4·a4)2), with kc (mol·gcat–1·min–1) = 1.52 × 107 – 66 988/(RT) and K4 = 1.589. Also equilibrium experiments were carried out. The proposed equilibrium equation was Keq = exp((−(1490 ± 577)/T + (7.21 ± 1.67)). From this equation, it was possible to determine the reaction standard enthalpy and entropy values: ΔH° = 12.39 ± 4.80 [kJ/mol] and ΔS° = 59.98 ± 13.87 [J/mol·K].

Comparison of heavy metal ions removal from industrial lean amine solvent using ion exchange resins and sand coated with chitosan

The accumulation of heavy metal ions in natural gas sweetening unit causes problems such as corrosion, foaming and fouling of the equipment. Heavy metal ions being chelated to lean amine solvent cannot be removed from the solvent by simple heating in the regenerator, hence requiring new approaches for heavy metal ions removal from aqueous solution of lean amine (methyldiethanolamine) solvent is mandatory. In this study, three different grades of commercial ion exchange resins (A–C) including chitosan coated Resin C and sand coated with chitosan (SCC) were tested to remove major heavy metal ions from raw industrial lean amine (MDEA) solution employing the principles of adsorption. Finally, Resin C and SCC were used for elaborate batch and continuous adsorption studies. SEM and FTIR analysis mapped the surface morphology changes and coating of chitosan before adsorption process over the adsorbent. The equilibrium batch sorption studies for heavy metal ions removal were fitted into Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) isotherms The Langmuir model predicted maximum uptake capacity for chitosan coated resin C and SSC (in brackets) 38.022 (14.184) μg/g for chromium, 59.88 (75.7575) μg/g of iron and 22.47 (185.185) μg/g of lead having total maximum metal removal of 6.858 (5.0226) μequivalence/g. The sorption kinetics obeys pseudo-first-order having rate constant 0.0111 min−1 (0.0095 min−1) for chromium ions. The negative values of Gibb's free energy explains spontaneity of the reaction with endothermic heat of adsorption for the removal of heavy metal ions using resin C and SCC. The breakthrough curves for removal of metal ions in column bed with 2.54 cm column diameter and flow rate of 4.5 ml/min was achieved within 8 h. The parameters k and τ for chitosan coated resin C and SCC were determined to be 0.014 (0.015) min−1 and 551.25 (525.7867) min.

The effect of the metal precursor-reduction with hydrogen on a library of bimetallic Pd-Au and Pd-Pt catalysts for the direct synthesis of H2O2

Two sets of bimetallic Pd-Pt (Pd: 1.0; Pt: 0.25-1.0%, w/w) and Pd-Au (Pd: 1.0; Au: 0.25-1.0%, w/w) catalysts have been used, with no added promoter, in the catalytic direct synthesis (CDS) of hydrogen peroxide from its elements at 2°C with a CO2/O2/H2 mixture (72/25.5/2.5%, respectively). The catalysts were supported on the commercial macroreticular ion-exchange resin Lewatit K2621 and were obtained from the reduction with H2 of ion-exchanged cationic precursors at 5bar and at 60°C. The addition of Pt or Au to Pd produced an increase of the initial overall catalytic activity in comparison with monometallic Pd with both the second metals, but with Pt the increase was much higher than with Au. Moreover, the addition of 0.25% (w/w) Pt, or more, invariably made all the Pd-Pt catalysts less selective with respect to Pd alone. In the case of Au, by contrast, the addition of 0.25% w/w produced an increase, albeit small, of the selectivity. As the result, the most active and productive Pd-Pt catalyst was 1Pd025PtK2621 with 1891 mol(H2) mol(Pd+Pt)−1 h−1 initially consumed, 1875 mol(H2O2) mol(Pd+Pt)−1 h−1 initially produced, a 45% selectivity towards H2O2 at 50% conversion of H2. In the case of the Pd-Au bimetallic catalysts, 1Pd025AuK2621 was the best one, with 1184 mol(H2) mol(Pd+Pt)−1 h−1 initially consumed, 739 mol(H2O2) mol(Pd+Pt)−1 h−1 initially produced, a 55% selectivity towards H2O2 at 50% conversion of H2. Although the characterization of the Pd-Pt and Pd-Au catalysts with TEM showed that the morphology of the nanostructured metal phases in the Pd-Pt and Pd-Au catalysts was very different from each family to the other, no clear correlation between the size of the nanoparticles and their distribution and the catalytic performance was apparent. These catalysts were also generally different, especially the Pd-Au ones, from previously reported related materials obtained from the same support and the same precursor, but with a different reducing agent (formaldehyde).

Rapid Preparation of Biosorbents with High Ion Exchange Capacity from Rice Straw and Bagasse for Removal of Heavy Metals

This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (∼3.62 meq/g) and shorter reaction time (1.5–5.0 min) than the phosphorylation by oil bath heating. Adsorption experiments towards Pb2+, Cd2+, and Cr3+ ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40 ppm, adsorbent 2.0 g/L). The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax). As a result of Pb2+ sorption test, the modified rice straw (RH-NaOH 450W) removed Pb2+ much faster in the initial step and reached 92% removal after 20 min, while Dowax (commercial ion exchange resin) took 90 min for the same removal efficiency.

Liquid phase oxidation of glycerol in batch and flow-type reactors with oxygen over Au–Pd nanoparticles stabilized in anion-exchange resin

Au–Pd bimetallic nanoparticles for selective oxidation of glycerol were successfully prepared in a commercial ion-exchange resin.

Development of Powerful Bacterial Biosorbent Fibers for Recovery of Ruthenium and Comprehension of the Role of Bacterial Biomass in the Fiber

The main purpose of this work is to develop and evaluate the fibrous bacterial biosorbents and to undestand the role of bacterial biomass in functionalizing polyethylenimine (PEI)-coated bacterial biosorbent fiber (PBBF). For this, chitosan fiber (CSF) and chitosan/biomass composite fiber (CSBF) were separately prepared by extruding chitosan solution and chitosan/biomass suspension, respectively. To make PBBF, the CSBF was coated with PEI and then cross-linked by glutaraldehyde. An acetic acid waste solution containing the initial ruthenium concentration of 1822.9 mg/L was used as a model waste solution. Batch sorption studies showed that the maximum Ru uptake of PBBF was 110.5 mg/g, which was 16.5 times higher than that of the commercial ion exchange resin, Lewatit MonoPlus M600. In addition, the thin fiber type of biosorbent showed as fast sorption kinetics as powder form of the raw biomass. Therefore, PBBF was evaluated as a promising biosorbent for recovery of Ru from Ru-containing acetic acid waste solutions. The role of biomass in the fiber was also investigated through sorption experiments and SEM, FTIR and XPS analyses with differently prepared fiber sorbents. In the case that the CSF was made without the biomass, it could not be coated with PEI. Meanwhile, the CSBF could successfully coat with PEI and primary amine groups were significantly increased on the surface of the fiber. Therefore, it can be concluded that the biomass should be essential to make PEI-reinforced chitosan fiber and that the negatively charged carboxyl groups on the biomass give the driving force for binding of cationic polymer PEI.

Microsized particles of Aza222 polymer as a regenerable ultrahigh affinity sorbent for the removal of mercury from aqueous solutions

This paper reports the preparation and characterization of a microparticulate sorbent based on a novel p-xylylene-peraza[2.2.2]cryptand (Aza222) polymer that exhibits selectivity and high affinity for mercury cations [1–3]. The sorbent particles dispersed into an aqueous suspension were characterized in terms of surface morphology, size distribution, porosity, and surface charge. Based on measured adsorption isotherms, two possible mechanisms of adsorption by this novel sorbent are proposed: high affinity stoichiometric complexation of Hg2+ within the Aza222 cage, which proceeds until the stoichiometric capacity of the sorbent is saturated; then excess mercury removal by nonspecific physisorption onto the surface of the Aza222 polymer. The experimentally determined mercury loading capacity of the sorbent was in accord with stoichiometric calculations at both high (mg/L) and low (μg/L) concentrations, opening possibilities for the use of the polymer for mercury detection or other analytical applications. Desorption studies were carried out and a preliminary study demonstrated that the sorbent is regenerable. The mercury capacity and selectivity of the sorbent in the presence of calcium ions compared favorably against corresponding properties of both a commercial ion exchange resin used for mercury removal and a related but non-macrocyclic polyamine-based polymer. Density functional (B3LYP) calculations using the 6-31G* basis set for light elements (C, H, Li, N, O) and the LANL2DZ effective core potential and basis set combination were used to compute the relative stability constants of the various metal-cryptand complexes. The agreement between theoretical and experimental Ks values, where known, was generally excellent, supporting the prediction of unknowns. Of particular relevance to the experimental work herein, the calculated difference between log KS for Hg2+ vs. Ca2+ ion binding in the hexamethylated peraza[2.2.2]cryptand is 23.0, indicating an overwhelming preference for binding mercury in this all-nitrogen complexant model for the ligand covalently embedded in the Aza222 polymer sorbent.

Selective oxidation of 5-hydroxymethyl-2-furfural into 2,5-diformylfuran over VO2+ and Cu2+ ions immobilized on sulfonated carbon catalysts

Immobilization of vanadyl (VO2+) and cupric (Cu2+) ions on sulfonated carbon and their catalytic activity toward the aerobic oxidation of 5-hydroxymethyl-2-furfural (HMF) are described. The carbon material (C) was derived from commercial ion exchange resin (Amberlyst-15) by performing carbonization process. Subsequently, sulfonated carbon (CS) was prepared by treating C with 98% sulfuric acid. Finally, VO2+ and/or Cu2+ ions were immobilized on CS by ion exchange technique. The synthesized catalysts were characterized by X-ray diffraction (XRD), elemental analysis, Raman spectroscopy, and transmission electron microscopy (TEM). Interestingly, in the catalytic oxidation of HMF using these catalysts, 2,5-diformylfuran (DFF), a high-value chemical is found to be the major product. The VO2+ ion-immobilized catalyst (V-CS) exhibits highly stable catalytic activity without the leaching of vanadyl ion during recycling tests, with low selectivity to DFF. The copper counterpart (Cu-CS), however, shows the opposite behavior, i.e., high selectivity to DFF and decreasing catalytic performance due to the leaching of copper component during recycling runs. The presence of copper in low concentrations in the vanadyl-exchanged catalyst (V-Cu-CS) leads to high selectivity to DFF and good re-usability. A catalyst with the composition 0.93%V–0.26%Cu-CS exhibits the best performance.

PVA supported catalytic membranes obtained by γ-irradiation for biodiesel production

PVA supported catalytic membranes have been synthesized by mutual γ-irradiation method using adipic acid (AA) and succinic acid (SA) as crosslinkers and a commercial ion exchange resin as catalyst.These membranes were tested as catalyst under batch conditions in esterification reaction of lauric acid to methyl laurate aiming biodiesel production. The effect of different synthesis parameters such as crosslinker, crosslinker's concentration and absorbed dose on membranes’ physical–chemical properties and catalytic activity was studied. Results demonstrated that PVA supported resin membranes are effective catalysts in the lauric acid esterification reaction. Also showed that PVA-SA membranes exhibit the better catalytic properties and, within the range of conditions studied, an increase in the γ-radiation dose leads to a slight increase of membranes’ catalytic activity.

Preparation of highly graphitized porous carbon from resins treated with Cr6+-containing wastewater for supercapacitors

A commercial ion exchange resin was used to remove Cr2O72− from Cr6+-containing wastewater, which was carbonized to produce porous carbon possessing a high graphitic degree and large specific surface area. Symmetric supercapacitors based on this porous carbon exhibited superior rate capability.

Recovery of metallic palladium from hydrochloric acid solutions by a combined method of adsorption and incineration

This study evaluated the recovery of palladium (Pd) by ion exchange resins from hydrochloric acid solutions using a combined method of adsorption and incineration. Lewatit MonoPlus TP 214 was selected as a representative commercial ion exchange resin and its adsorption performance was evaluated. Kinetic and isotherm experiments revealed that Pd(II) adsorption equilibrium was reached within 21h, and the maximum uptake estimated by the Langmuir model was 241.1±11.6mg/g. To recover Pd as a solid form, the Pd ions-loaded resin was incinerated. The effects of incineration temperature and Pd amount were examined to enhance the recovery efficiency and purity of the recovered Pd. SEM–EDX and XRD analyses were used to confirm existence of Pd phase in ash incinerated in air at 600°C and 900°C. Both the incineration temperature and Pd amount significantly affected the recovery efficiency and purity. The form of Pd was changed from PdO to Pd0 as the incineration temperature was increased from 600°C to 900°C. At 900°C and 258.5mg/g of Pd(II) uptake, metallic Pd was successfully recovered with 99.0% of recovery efficiency and 96.1% of purity. Consequently, it can be claimed that the sorption–incineration process is likely an effective way enabling simple and fast recovery of precious metals as a metallic form from waste solutions.