Commercial Ion Exchange Resin Research Articles

Ion-exchange resins as catalysts in transesterification of triolein

The objective of the present study is to examine commercial ion exchange resins (IER) as heterogeneous catalysts at high temperatures for biodiesel production from triolein in a batch reaction system. Various commercial IER were screened as catalysts in transesterification of triolein and methanol. Of the catalysts tested, Amberlyst 15 was the most active catalyst in screening experiments. Reaction conditions were optimized within the experimental bounds using central composite design (CCD). At the optimized conditions, triolein conversion to products was 97mol%. In longevity experiments Amberlyst 15 was reused once with no loss in catalytic activity, while successive experiments demonstrated decreases in catalytic activity. Product acid value, addition of free fatty acids as well as water addition to the reactants indicate that hydrolysis and esterification side reactions are taking place at the optimized conditions. Reaction kinetics were examined at 100–120°C. A mathematical model of transesterification was developed in MATLab and demonstrated a close approximation to experimental data. For the three forward reactions: triglyceride to diglyceride, diglyceride to monoglyceride, and monoglyceride to glycerol, reaction rate constants are reported to be 9.3×10−7, 2.5×10−6, and 7.5×10−5L/mol/s. The first reversible reaction step converting triglycerides to diglycerides was found to be the rate limiting step. Activation energy for this step was 120kJ/mol.

Ruthenium recovery from acetic acid waste water through sorption with bacterial biosorbent fibers

A fibrous bacterial biosorbent was developed to bind precious metal–organic complexes in batch and column processes. Polyethylenimine (PEI)-modified bacterial biosorbent fiber (PBBF) was prepared by spinning Corynebacterium glutamicum biomass-chitosan blends, coating them with PEI and cross-linking with glutaraldehyde. When an acetic acid waste solution containing 1822.9mg/L Ru was used as a model waste solution, Ru uptake by the PBBF was 16.5 times higher than that of the commercial ion exchange resin, Lewatit MonoPlus M600. The maximum amounts of Ru uptake were 110.5, 16.0 and 6.7mg/g for PBBF, raw biomass, and Lewatit MonoPlus M600, respectively. In a flow-through packed bed, PBBF exhibited the breakthrough time of 42.32h. Therefore, PBBF can be considered as an alternative sorbent for recovery of anionic metal–organic complexes from waste solutions.

Release of Nanoparticles from Ion Exchange Resins and Their Detection

Nanoparticles released from commercial ion exchange resins were analyzed by laser-induced breakdown detection (LIBD). It was shown that virgin resins release a considerable amount of nanoparticles which may harm sensitive production lines, if the resins are used without proper pretreatment. Particle release is reduced to below 1 ppb after regeneration and rinsing of the resins. However, the nanoparticle concentration can still be detected quantitatively by LIBD.

Reversible immobilization of K. fragilis β-galactosidase onto magnetic polyethylenimine-grafted nanospheres for synthesis of galacto-oligosaccharide

Abstract A nanosized support for reversible immobilization of enzymes, magnetic poly(glycidyl methacrylate-ethylene glycol dimethacrylate-hydroxyethyl methacrylate) nanospheres grafted with polyethyleneimine, was prepared and characterized by scanning electron microscopy and vibrating sample magnetometry. The novel support displayed 3.2-fold higher adsorption capacity for Kluyveromyces fragilis β-galactosidase than commercial ion exchange resin DEAE-Sepharose, the maximum amount of the enzyme adsorbed on the support reached 86.7 mg/g with enzyme activity recovery of 92.5%. The adsorbed K. fragilis β-galactosidase showed high catalytic activity and operational stability for synthesis of galacto-oligosaccharide (GOS), 4.5 kg of GOS were produced per gram of adsorbed enzyme from lactose during 15 consecutive batch reactions by reuse of the same biocatalyst, and the immobilized biocatalyst retained about 84.6% of its initial activity after 15 cycles of batch operation. The support could be regenerated and reused, remaining 93.0% of its original adsorption capacity at the end of the twentieth adsorption–desorption cycle.

Evaluation of strongly acidic ion‐exchange catalysts and the desulfonation study in the isobutylene dimerization reaction

AbstractThree commercial ion‐exchange resin based catalysts were compared under different temperature and liquid‐volume hourly space velocity (LHSV) in the isobutene (IB, C4) dimerization reaction using a plug flow reactor in the absence of any selectivity enhancing component. High IB conversion for all catalysts was obtained at or higher than 50°C. But, diisobutene (DIB, C8) selectivity decreased with the increase of temperature. High C8 selectivity was observed with LHSV higher than 1.5 at 50°C. The best catalytic performance of the three resins did not show obvious differences. The effect of the selectivity enhancers on the stability of the resins was also studied. Desulfonation was observed in the C4 dimerization reaction when water or the commonly used enhancer tert‐butyl alcohol (TBA) was added to the feed. The deactivation of catalyst resulted in decrease of both IB conversion and C8 selectivity. Fourier Transform Infrared spectroscopy showed that desulfonation happened in both para and ortho positions of the sulfonated benzene rings. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Removal of mercury from aqueous solutions by adsorption on a new ultra stable mesoporous adsorbent and on a commercial ion exchange resin

The performance of two adsorbents, i.e. a new ultra stable adsorbent SH-ePMO and a commercial ion exchange resin TP-214, for the removal of mercury from aqueous solutions was investigated. The operating variables studied were initial mercury concentration and contact time. The adsorption isotherms showed favourable adsorption. The adsorption isotherms were analysed using Langmuir and Freundlich models. The Langmuir model yielded the best fit for the SH-ePMO, whereas the Freundlich model fitted best the adsorption on TP-214. The maximum adsorption capacities were 66 and 456 mg/g for SH-ePMO and TP-214, respectively. TP-214 is capable of purifying water to parts per trillion levels. The adsorption kinetics showed a fast adsorption for both adsorbents. The kinetics was analysed using Lagergren's pseudo-first-order and pseudo-second-order kinetic models. The pseudo-first-order kinetic model showed a good description of the experimental data of both adsorbents. This study clearly shows the potential of the ultra stable SH-ePMO for removing mercury from aqueous solutions and confirms the performance of the ion exchanger resin TP-214.

Facile heterogeneous catalytic hydrogenations of CN and CO bonds in neat water: anchoring of water-soluble metal complexes onto ion-exchange resins

Rare examples are known of non-covalent immobilization of water-soluble transition metal complexes onto solid supports and their application in catalytic hydrogenations in neat water. In the present work we report on the synthesis of a novel Ir(I) complex bearing the water soluble monodentate cage phosphine PTA (PTA = 1,3,5-triaza-7-phosphaadamantane) and its immobilisation onto commercial ion-exchange resins by a straightforward heterogenization method. The materials obtained were used as catalysts for the hydrogenations of cyclic imines and α-keto esters under mild conditions using water as a green reaction medium, avoiding as much as possible the use of toxic and/or hazardous solvents.

Synthesis of Mesoporous Zirconium Organophosphonate Solid‐Acid Catalysts

AbstractMesoporous zirconium phosphonate materials with bridged organic groups in the framework were hydrothermally synthesized with 1‐hydroxyethylidene‐1,1‐diphosphonic acid as coupling molecule and cetyltrimethylammonium bromide as template. The mesostructure is wormhole‐like with a specific surface area of 702 m2/g and a uniform pore size of 3.6 nm, and the organophosphonate groups are homogeneously integrated in the network of the obtained solids. The hydroxyethylidene‐bridged mesoporous zirconium phosphonates can serve as solid‐acid catalysts for the synthesis of methyl‐2,3‐O‐isopropylidene‐β‐D‐ribofuranoside from D‐ribose and exhibit high catalytic activity with rapid reaction rate, which are comparable to the catalytic performance when liquid acid HCl or commercial ion‐exchange resin NKC‐9 is used as catalyst. Furthermore, mesoporous zirconium phosphonates show high stability with good reusability without any loss of catalytic activity after five cycles, which demonstrates their potential for industrial applications.

Energy Recovery from Acid–Base Neutralization Process through pH-Sensitive Polymeric Ion Exchangers

Globally speaking, waste acid neutralization is a widely used industrial pollution control process. In principle, acid–base neutralization is a thermodynamically favorable reaction that involves the association of hydrogen and hydroxyl ions to form neutral water molecules with the generation of a significant amount of thermal energy (ΔH = −55.84 kJ/mol). However, it is not possible to recover the energy, because the increase in temperature of the bulk solution phase is often miniscule, because of the diluted nature of the waste acid solution and the high specific heat of water. Here, we demonstrate a methodology to recover a significant amount of useful energy by carrying out the neutralization reaction inside a pH-sensitive hydrophilic polymer (or biopolymer) phase containing covalently attached weak-acid or weak-base functional groups. When contacted with an acid or a base, the variation of pH causes the functional groups to reversibly acquire and lose its ionic character. This gives rise to an on–off pattern regarding the generation of osmotic pressure inside the polymer phase, causing it to reversibly swell and shrink, because of the movement of water into and out of the polymer phase. Laboratory experiments validate the reversibility of the swelling–shrinking pattern of a commercial weak-acid ion-exchange resin for multiple numbers of cycles with a concomitant generation of mechanical energy during the neutralization reaction. The process can be enhanced by tailoring the cross-linking and hydrophilicity of the polymer phase. The energy generated is free of carbon emission.

Adsorption characteristics of copper ions using magnetically modified medicinal stones

To improve efficiency of adsorption process, magnetically modified medicinal stones (MMS) were developed by means of entrapment method with iron oxide and urethane. The MMS have the maximum uptake capacity of about 13.6 mg/g-dry mass for copper ions at pH 6. The adsorption mechanism can be explained as ion exchange between alkali earth metals and copper ions. The surface condition and adsorption of copper ions onto MMS were confirmed by ESEM and EDAX. MMS could remove copper ions of about 93% with 1.5 g and the adsorption equilibrium of MMS was faster than that of commercial ion exchange resin (IR-120 plus resin) by about 50 min.

Carbon dioxide sequestration through novel use of ion exchange fibers (IX-fibers)

Electrical power generation and metal removal processes are practiced globally and share two common attributes that make them ideal candidates to be incorporated in a novel carbon dioxide sequestration scheme using ion exchange fibers (IX-fibers). First, the softening of boiler feed water used in power generation and the removal of metals from finishing wastewaters often employs the use of ion exchange for the purpose of selective separation. Second, both processes represent significant point source CO 2 emissions. This investigation demonstrated that using IX-fibers it is possible to sequester a portion of the CO 2 produced in these practices as carbonate alkalinity during the regeneration step of both the water softening and the trace heavy metal removal processes. Weak acid IX-fibers were used for hardness removal while hybrid cation exchange fibers (HCIX-F) loaded with hydrated Zr(IV) oxide (HZO) were used to remove toxic heavy metals such as zinc, cadmium and copper. IX-fibers offer the unique capability to use and consume CO 2 during the efficient regeneration of IX-fibers, whereas commercial ion exchange resins are not amenable to regeneration with CO 2. A much shorter intraparticle diffusion path length in cylindrical IX-fibers as compared to resin beads is the underlying reason for a highly efficient regeneration of the fibers. In addition to sequestering carbon dioxide, no hazardous or aggressive chemicals/brine solutions are present in the regenerant wastes as compared with traditional ion exchange processes.

An investigation into transition metal ion binding properties of silk fibers and particles using radioisotopes

AbstractSilk is a structural protein fiber that is stable over a wide pH range making it attractive for use in medical and environmental applications. Variation in amino acid composition has the potential for selective binding for ions under varying conditions. Here we report on the metal ion separation potential of Mulberry and Eri silk fibers and powders over a range of pH. Highly sensitive radiotracer probes, 64Cu2+, 109Cd2+, and 57Co2+ were used to study the absorption of their respective stable metal ions Cu2+, Cd2+, and Co2+ into and from the silk sorbents. The total amount of each metal ion absorbed and time taken to reach equilibrium occurred in the following order: Cu2+ > Cd2+ > Co2+. In all cases the silk powders absorbed metal ions faster than their respective silk fibers. Intensive degumming of the fibers and powders significantly reduced the time to absorb respective metal ions and the time to reach equilibrium was reduced from hours to 5–15 min at pH 8. Once bound, 45–100% of the metal ions were released from the sorbents after exposure to pH 3 buffer for 30 min. The transition metal ion loading capacity for the silk sorbents was considerably higher than that found for commercial ion exchange resins (AG MP‐50 and AG 50W‐X2) under similar conditions. Interestingly, total Cu2+ bound was found to be higher than theoretically predicted values based on known specific Cu2+ binding sites (AHGGYSGY), suggesting that additional (new) sites for transition metal ion binding sites are present in silk fibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Modification of Rice Straw for Heavy Metal Ion Adsorbents by Microwave Heating

AbstractSummary: Cellulose in rice straw was chemically modified by phosphorylation using conventional heating or microwave heating. Rice straw pretreated by NaOH solution gave the highest phosphorus content when it was phosphorylated using microwave heating at 450 watt (7.07%P, ion exchange capacity 2.60 meq/g). The 3 hour‐reaction in oil bath yielded the modified rice straw with lower of phosphorus content (6.32%P) and higher ion exchange capacity (2.99 meq/g) than that of microwave heating. The feasibility of the modified rice straw as cation sorbents for removing heavy metal was investigated. Cd2+, Cr3+ and Pb2+ were used as sorbates. In sorption test of 40 ppm with 2.0 g/L of the modified rice straw, both modified rice straws could adsorb metal ions faster than the commercial ion exchange resin (dowax) at the time less than 60 min. The modified rice straw prepared by microwave heating (A‐MCW2) could remove 90% of Cd2+ and Cr3+ in 60 minutes and remove 99% of Pb2+ after 30 min.

Synthesis, structure, and selective separation behavior of copper‐imprinted microporous polymethacrylate beads

AbstractMetal ion‐imprinted polymethacrylate beads with sizes ranging from 100 to 300 μm were prepared by suspension polymerization for the application of selective separation of target metal ions. The metal ion contacting area of the beads was enlarged via pore formation (BET 425 m2/g) using toluene as a porogenic agent. The synthesis of the copper‐imprinted porous beads was verified using FTIR, SEM, and ESCA. Separation capacity and selectivity were investigated carrying out column separation experiments. The selective adsorption behavior of the imprinted beads was significantly affected by flow rate, pH, and metal ion concentration in the solution. Adsorption of the copper ion, the template metal ion, onto the beads was highly selective, compared with other ions such as nickel and zinc, with the selective coefficients at approximately 5–10. The microporous particles possessing such high selectivity has a potential application as novel column packing materials especially requiring high selective efficiency, which is usually not achievable by commercial ion exchange resins. © 2009 American Institute of Chemical Engineers AIChE J, 2009

Catalytic etherification of glycerol by tert-butyl alcohol to produce oxygenated additives for diesel fuel

The heterogeneous catalytic etherification of glycerol with tert-butyl alcohol was investigated in presence of lab-made silica supported acid catalysts. As reference, two commercial acid ion-exchange resins were also used. Experiments were carried out in batch mode at T R ranging from 303 to 363 K. An increase in reaction temperature favors the formation of di-substituted ethers. The etherification reaction proceeds according to a consecutive path and the surface reaction between adsorbed glycerol and protonated tert-butanol (tertiary carbocation) can be considered as the rate determining step. Steric hindrance phenomena and water hinder the formation of tri-substituted ether (TBGE). As expected, water removal was necessary to allow the higher ethers formation. The specific activity (turnover frequency, TOF) of A-15 catalyst is significantly higher than that of the other studied acid systems, due to the wide pore diameter that allows an easier accessibility of the reagent molecules.

Flue Gas Carbon Dioxide Sequestration during Water Softening with Ion-Exchange Fibers

This study examines the use of ion-exchange fibers (IX fibers) to permanently sequester carbon dioxide present in flue gas into an aqueous phase as calcium or magnesium alkalinity while concurrently softening hard water. The only process inputs besides carbon dioxide (or flue gas) are snowmelt (or rainwater); no other chemicals are required for the regeneration of the IX fibers. Importantly, the process is not energy intensive and carbon dioxide does not need to be compressed to excessive pressures (>150psi) for efficient use. Sources of carbon dioxide do not require concentration and, therefore, the use of raw flue gas (∼17%CO2) is feasible with the rate of sequestration governed only by the partial pressure of carbon dioxide. While valid for flue gas obtained from any combustion process (e.g., coal, oil, natural gas, etc.), emissions from oil or gas combustion may be more appropriate for use in the described process due to the absence of mercury and particulates. It should also be noted that the presence of sulfur dioxide in flue gas would not adversely affect the process and may even enhance regeneration efficiency. The only product of the proposed process is an environmentally benign regenerant stream containing calcium and/or magnesium alkalinity. The unique property of IX fibers that makes the proposed process both environmentally sustainable and economically feasible is amenability to efficient regeneration with carbon dioxide and harvested snowmelt. Low intraparticle diffusional resistance is the underlying reason why IX fibers are amenable to efficient regeneration using snowmelt sparged with carbon dioxide; 95% calcium recovery was attained at a CO2 partial pressure of 6.8atm. On the contrary, commercial weak-acid ion-exchange resins in spherical bead forms are ineffective for regeneration with carbon-dioxide-sparged snowmelt due to extremely slow ion-exchange kinetics involving counter-transport of Ca2+ (or Mg2+) and H+. The energy balance for a typical electric utility shows that up to 1% of carbon dioxide emitted during combustion would be sequestered in the softening process.

Liquid-phase synthesis of ethyl tert-butyl ether over acid cation-exchange inorganic–organic resins

In this study the possibility to increase the productivity of acid cation-exchange resin catalysts active sites in ETBE synthesis was elucidated. For this purpose the inorganic–organic sulfonated cation-exchange resins with different polymer loadings (1.5–9.2 wt.%) have been synthesized. Such polymer/carrier composites as well as commercial acidic microporous gel-type ion-exchange resin KU-2-8 and macroporous Amberlyst 15 have been studied in the ETBE synthesis. Acid properties of all solids were determined by quasi-equilibrium thermogravimetry of ammonia desorption. We have found out that polymer loading and acid capacity affect oppositely on the ETBE productivity. As a result, there is no direct correspondence between the ETBE productivity of the inorganic–organic sulfonated cation-exchange resins per gram of catalyst on their acidity. However, there is a linear relation between the productivity per gram of polymeric phase and acidity. It was established that due to a better accessibility of acid sites for reactants loaded sulfonated cation-exchange resins exceeds the commercial catalysts by the site time yield values.

A comparative study of alginate beads and an ion-exchange resin for the removal of heavy metals from a metal plating effluent

The capacity of dry protonated calcium alginate beads to sorb metals from an industrial effluent was studied and compared with a commercial ion-exchange resin (Lewatit TP 207). Both sorbents decreased zinc, nickel, iron and calcium concentrations in the effluent, and released sodium during treatment. Alginate beads removed lower amounts of heavy metals than the resin, but exhibited faster uptake kinetics. Zinc desorption from the sorbents was achieved in 30 minutes using 0.1 M HCl or 0.1 M H2SO4. Desorption ratios with these acids varied between 90 and 100% for alginate, and 98 to 100% for the ion-exchange resin. Reusability tests with HCl showed that alginate beads can stand acid desorption and recover binding capacity. Overall, the comparison of dry protonated alginate beads with the resin supports the potential of the biosorbent for the treatment of industrial effluents.

Removal of Pertechnetate from Simulated Nuclear Waste Streams Using Supported Zerovalent Iron

The application of nanoparticles of predominantly zerovalent iron (nanoiron), either unsupported or supported, to the separation and reduction of pertechnetate anions (TcO4-) from complex waste mixtures was investigated as an alternative approach to current waste-processing schemes. Although applicable to pertechnetate-containing waste streams in general, the research discussed here was directed at two specific potential applications at the U.S. Department of Energy's Hanford Site: (1) the direct removal of pertechnetate from highly alkaline solutions, typical of those found in Hanford tank waste, and (2) the removal of dilute pertechnetate from near-neutral solutions, typical of the eluate streams from commercial organic ion-exchange resins that may be used to remediate Hanford tank wastes. It was envisioned that both applications would involve the subsequent encapsulation of the loaded sorbent material into a separate waste form. A high surface area (>200 m2/g) base-stable, nanocrystalline zirconia was used as a support for nanoiron for tests with highly alkaline solutions, while a silica gel support was used for tests with near-neutral solutions. It was shown that after 24 h of contact time, the high surface area zirconia supported nanoiron sorbent removed about 50% (Kd = 370 L/kg) of the pertechnetate from a pH 14 tank waste simulant containing 0.51 mM TcO4- and large concentrations of Na+, OH-, NO3-, and CO32- for a phase ratio of 360 L simulant per kg of sorbent. It was also shown that after 18 h of contact time, the silica-supported nanoiron removed >95% pertechnetate from a neutral pH eluate simulant containing 0.076 mM TcO4- for a phase ratio of 290 L/kg. It was determined that in all cases, nanoiron reduced the Tc(VII) to Tc(IV), or possibly to Tc(V), through a redox reaction. Finally, it was demonstrated that a mixture of 20 mass % of the solid reaction products obtained from contacting zirconia-supported nanoiron with an alkaline waste solution containing Re(VII), a surrogate for Tc(VII), with 80 mass % alkali borosilicate based frit heat-treated at 700 °C for 4 h sintered into an easily handled glass composite waste form.

Adsorptive separation of fructose and glucose from an agroindustrial waste of cashew industry

Nearly all agroindustrial wastes have appreciable sugar content including cashew apples ( Anacardium occidentale, L.), which are an important sub-utilized biomass source in Northeastern Brazil. Adsorption in fixed bed, both in batch and continuous modes, is a low-cost separation technique, which has been widely used in the concentration, separation and purification of bioproducts, such as sugars. The present work is an experimental study aimed at measuring responses in fixed bed, needed for design purposes. Two commercial ion-exchange resins were studied: DOWEX Monosphere 99/Ca and DIAION UBK555. The adsorbents showed linear isotherms for both sugars with marked selectivity for fructose (2.2 for DOWEX and 1.5 for DIAION). A mathematical model was used to estimate kinetic parameters and predict breakthrough behaviour of binary solutions and complex feeds. The kinetics of mass transfer was well described by a linear driving force approximation (LDF) and estimated kinetic constants were around 1 min −1. The results indicate that the use of independent experiments with synthetic monocomponent solutions leads to reliable parameters, and the model is capable to foresee reasonably well the breakthrough curve of the sugars present in the juice, under different purification conditions. The use of complex feeds led to overshoot behaviour, possibly due to the irreversible adsorption of oligosaccharides.