Acid Ion Exchange Research Articles

ChemInform Abstract: Alternative Fuel Additives from Glycerol by Etherification with Isobutene: Structure‐Performance Relationships in Solid Catalysts

AbstractReview: 154 refs.

The Oligomerization of Olefin Hydrocarbons in Light FCC Naphtha on Ion Exchange Resin Catalyst

In our experimental work our aim was the investigation of the possibility to convert olefin hydrocarbons of a light FCC naphtha fraction with oligomerization. In this framework, we studied the production possibilities of higher carbon number isoolefin rich motor fuel blending components, with oligomerization of the C4-C6 olefin content of the feedstock on water-containing acidic ion exchange resin catalysts. From the studied catalysts the ion exchange resin showed the highest oligomerization activity: the conversion of the olefins was 90.9 % and the share of oligomer products was 29.0 %. After hydrogenation of the C8-C16 isoolefin mixture, the octane number of gasoline product is around 100, the JET product has high energy content and low crystallization point, the cetane number of gas oil product is high and it has a good CFPP (cold filter plugging point). So with these two catalytic steps valuable products can be produced from light olefin-containing refinery by-products.

External liquid solid mass transfer for solid particles transported in a milli-channel within a gas–liquid segmented flow

This article focuses on the measurement of external liquid–solid mass transfer coefficient for micro-particles (dP=40–200μm) transported in a gas–liquid Taylor flow. The particles are kept in motion due to the secondary vortices present in the liquid slugs of these segmented flows. Acidic ion exchange particles and dilute sodium hydroxide solutions are used to perform ion exchange and neutralisation under external mass transfer limitations. Concentration profiles are monitored along the reactor with 4 conductivity cells which provides accurate mass transfer coefficients for each experiment. Two phase velocity (2.5–28cm/s), mean particle size (100–160μm), solid loading (5–18g/L), reactor orientation (vertical down flow-horizontal) and liquid phase nature (Sc=790–2300) were investigated. In that experimental window, it was found that the solid charge and the flow direction have a small influence on the L–S mass transfer even though the direction of the flow influences particle distribution in the liquid slug. Similar mass transfer coefficients and dependencies on the two phase velocities and liquid properties were found. Increasing the two-phase velocity leads first to increase the mass transfer coefficient. Then at highest velocities (uTP>20cm/s), a much lower impact is observed and the mass transfer coefficient tends to stabilize. A first correlation form for the L–S Sherwood number in “slurry Taylor” flow is proposed for both flow orientations. These findings are used in a second part to illustrate the high potentialities of this advanced structured flow in comparison with other conventional reactors using suspended particles like stirred tank and bubble column reactors. The G–L–S “slurry Taylor” offers compelling advantages combining excellent overall external mass transfer (G–L and L–S) and almost ideal plug flow behaviour for the three phases and very good heat transfer capacities.

Catalytic Activity and Accessibility of Acidic Ion-Exchange Resins in Liquid Phase Etherification Reactions

Although macroreticular acidic ion-exchange resins have been widely used as catalysts in the industrial world for decades, their catalytic behavior is still far from being completely understood at a molecular level. Several characterization techniques coexist, which provide information about their properties. Only few of these techniques give an actual picture of their working-state features when swollen in anhydrous polar reactive media such as in etherification processes, where they are extensively used. The inverse steric exclusion chromatography technique, based on modeling the micropores structure, or gel-phase, as a set of discrete volume fractions with a characteristic polymer chain density, constitutes an appropriate procedure to assess the morphology of ion-exchangers in the swollen state. Present work proposes an empirical model to correlate the properties of the volume fractions with their catalytic activity in the etherification reaction rates of isobutene by addition of C1–C4 linear primary alcohols. Sixteen different macroreticular acidic ion-exchange catalysts, both commercial and lab-made, have been used, which differ in acid capacity, sulfonation type, cross-linking degree and swollen-phase volume fractions distribution. Experimental reaction rates have been expressed as a sum of contributions of each individual volume fraction. The contribution of each polymer volume fraction corresponds to the product of the catalyst acidity, the characteristic volume fraction within the gel-phase of the catalyst, and a specific turnover frequency of that fraction. Accessibility of the reacting alcohol, expressed in terms of the Ogston coefficient, has been also included in the empirical dependency equation presented in this work.

Oligomerization of Light FCC Naphtha with Ion Exchange Resin Catalyst

There is a great importance to those processes which are producing from the lower value light hydrocarbons (C3–C6 paraffins and olefins) heavier and more valuable products (gasoline or middle distillate). In the hydrocarbon industry proven technologies already exist for the application of acidic ion exchange resin catalysts (e.g. synthesis of ethers). Our objective was to study the selectivity in oligomerization of a distillated FCC naphtha feedstock with ion exchange resins, in function of catalyst properties and operating conditions. In our experimental work we investigated the applicability of acidic ion exchange resins (5.46 and 4.98 eqH+kg−1 acidity; 31 and 52 m2g−1 surface area; 243 and 298 A pore size; respectively) alone and in premixed bed in case of 80–140 °C temperature, 15–40 bar pressure and 0.5–3.0 h−1 LHSV. In case of premixed catalyst bed both the olefin conversion (98–99 %) and the share of heavier oligomers (C12+ share: 40–49 %) increased compared to the share of C8–C11 oligomer products. The application of premixed bed was also investigated during a more than 600-h experiment.

Recovery of indium from TFT and CF glasses of LCD wastes using NaOH-enhanced sub-critical water

Recently, we reported that 83% indium was recovered from CF glass and 10% from TFT glass of LCD panel wastes using sub-critical water at 360°C. In the present work, in order to increase the recovery of indium in the form of indium tin oxide (ITO) and to reduce the reaction temperature, the effect of basic materials and their concentrations in sub-critical water on its recovery were tested. The basic materials were NaOH, KOH, Na2CO3, diethyl amine, Ca(OH)2 and NH3. NaOH showed the largest recovery of indium from both CF and TFT glasses and reduced the reaction temperature. Treatment for only 5min resulted in an outstanding indium recovery of 95% at 220°C from TFT glass and 99% at 160°C from CF glass. After the treatment, both TFT and CF glasses became transparent. ITO did not dissolve in the liquid-phase but remained in the solid organic multi-layers that were separated from the TFT and CF glasses by the sub-critical water reaction. These organic multi-layers were readily recovered by filtration. Since no indium dissolved in the liquid-phase, this recovery method is superior to others such as acid dissolution and ion-exchange. The optimum requirement of NaOH concentration and reaction time for indium recovery was 0.1N and 5min, respectively. The present result showed a significant improvement in indium recovery compared to our previous result without NaOH. Thus, sub-critical water in the presence of NaOH is highly feasible for the recovery of indium from TFT and CF glasses.

Isolation of a thermostable acid phytase from Aspergillus niger UFV-1 with strong proteolysis resistance.

An Aspergillus niger UFV-1 phytase was characterized and made available for industrial application. The enzyme was purified via ultrafiltration followed by acid precipitation, ion exchange and gel filtration chromatography. This protein exhibited a molecular mass of 161 kDa in gel filtration and 81 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), indicating that it may be a dimer. It presented an optimum temperature of 60 °C and optimum pH of 2.0. The K M for sodium phytate hydrolysis was 30.9 mM, while the k cat and k cat / K M were 1.46 ×10 5 s −1 and 4.7 × 10 6 s −1 .M −1 , respectively. The purified phytase exhibited broad specificity on a range of phosphorylated compounds, presenting activity on sodium phytate, p-NPP, 2- naphthylphosphate, 1- naphthylphosphate, ATP, phenyl-phosphate, glucose-6-phosphate, calcium phytate and other substrates. Enzymatic activity was slightly inhibited by Mg 2+ , Cd 2+ , K + and Ca 2+ , and it was drastically inhibited by F − . The enzyme displayed high thermostability, retaining more than 90% activity at 60 °C during 120 h and displayed a t 1/2 of 94.5 h and 6.2 h at 70 °C and 80 °C, respectively. The enzyme demonstrated strong resistance toward pepsin and trypsin, and it retained more than 90% residual activity for both enzymes after 1 h treatment. Additionally, the enzyme efficiently hydrolyzed phytate in livestock feed, liberating 15.3 μmol phosphate/mL after 2.5 h of treatment.

Modeling of Ni2+ exchange on the strong acid ion-exchange resin and the organic-inorganic ion exchanger

Currently, for calculations of processes in the ion-exchange columns is used the model which require the use of parameters such as diffusion coefficients of the ions in solution and the ion exchanger, exchange capacity, selectivity coefficients, and particle size of the ion exchanger and bed height, velocity of the solution. The greatest difficulty is the definition of the diffusion coefficient of exchanging ions in the ion exchanger, as this parameter varies with the degree of substitution of the resin and is very dependent on the presence of other ions in solution. In this regard, the actual task is creating a formalized process model in a dynamic mode, which allows minimizing the number of parameters, eliminating the diffusion coefficients and selectivity. The aim of research is creation of a formalized model of ion exchange, taking into account only empirical parameters.It is investigated the strongly acidic gel ion exchanger modified by aggregates of nanoparticles of zirconium hydrogen phosphate. In dynamic mode it was performed deionization of combined solution prepared in tap water, which contains ions of calcium, magnesium and nickel.Under dynamic conditions it is investigated extract of nickel ions from the combined solution by using a strongly acidic gel cation exchange resin and the composite ion exchanger on its base, containing aggregates of nanoparticles of zirconium hydrogen phosphate. A model is proposed, which allows determining the time at which the capacity is reached before breakthrough for nickel ions. This model involves the use of only empirical parameters obtained in the investigation of ion exchange in a dynamic mode, reflecting the concentration of ions in the solid phase and does not require prior identification and selectivity coefficient of diffusion of sorbed ions, and the communication mode (external and internal diffusion or mixed).

Preparation of highly purified 68Ga solutions via ion exchange in hydrochloric acid–ethanol mixtures

The ion-exchange behavior of 68Ga in mixed HCl–ethanol media on cation and anion exchangers was studied. The mass distribution coefficients of 68Ga on Dowex 50 W × 8 and Dowex 1 × 8 ion-exchange resins at HCl concentrations in the range 0.1–3.0 M and with ethanol volume fractions 0–90 % were determined. The dynamic characteristics of the 68Ga ion exchange in mixed HCl–ethanol solutions were studied. A process, based on the data obtained, was developed for preparing of 68Ga solutions in 0.1 M HCl with high chemical and radiochemical purity that are suitable for producing of 68Ga-radiopharmaceuticals with required quality for clinical use. The suitability of the process for the synthesis of different 68Ga-radiopharmaceuticals in routine clinical practice was demonstrated.

Ultrasound assisted synthesis of methyl butyrate using heterogeneous catalyst

Ultrasound assisted esterification of butyric acid with methanol was investigated in an ultrasound irradiated isothermal batch reactor using acid ion-exchange resin (amberlyst-15) as a catalyst. Effect of parameters such as temperature (323–353K), catalyst loading (0–8.5%w/w), alcohol to acid ratio, M (2–6), ultrasound power (0–145W), duty cycle (0–85%) and amount of molecular sieves added (0–11%w/w) on the rate of reaction was studied. At optimized parameters, a maximum conversion of 91.64% was obtained in 120min in presence of ultrasound. Experimental kinetic data were correlated by using Eley–Rideal (ER) and Langmuir–Hinshelwood–Hougen–Watson (LHHW) models taking into account reverse reaction. Studies showed that single site LHHW with reactants and products both adsorbing on catalyst surface was most suited for the obtained experimental data. Activation energy determined based on heterogeneous kinetics was in the range 49.31–57.54kJ/mol while it was 18.29kJ/mol using homogeneous model.

Novel catalyst PTMA-PILC: structural properties and catalytic performance for the dehydration of bioethanol to ethylene

Novel phosphomolybdic acid-pillared interlayer clay (PTMA-PILC) catalysts were prepared by three steps: acid treatment, ion-exchange and impregnation method.

Probing Ion Exchange in the Triflic Acid–Guanidinium Triflate System: A Solid-State Nuclear Magnetic Resonance Study

Knowledge of ion exchange and transport behavior in electrolyte materials is crucial for designing and developing novel electrolytes for electrochemical device applications such as fuel cells or batteries. In the present study, we show that, upon the addition of triflic acid (HTf) to the guanidinium triflate (GTf) solid-state matrix, several orders of magnitude enhancement in the proton conductivity can be achieved. The static 1H and 19F solid-state NMR results show that the addition of HTf has no apparent effect on local molecular mobility of the GTf matrix at room temperature. At higher temperatures, however, the HTf exhibits fast ion exchange with the GTf matrix. The exchange rate, as quantified by our continuum T2 fitting analysis, increases with increasing temperature. The activation energy for the chemical exchange process was estimated to be 58.4 kJ/mol. It is anticipated that the solid-state NMR techniques used in this study may be also applied to other organic solid-state electrolyte systems to i...

Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract

In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h.

Synthesis, characteristics and adsorption properties of polyphenylene sulfide based strong acid ion exchange fiber

A novel strong acid ion exchange fiber (HO3S-BC-XDC-PPS) was prepared via crosslinking and grafting copolymerization of 1,4-bischloromenthyl benzene (XDC), benzyl chloride (BC) on polyphenylene sulfide (PPS) matrix, as well as following sulfonation reaction. The physicochemical structures and properties of the fibrous ion exchanger were characterized with Fourier transform infrared, scanning electron microscopy, thermogravimetric analysis, elementary analysis and chemical titration, respectively. Compared with the preparation of traditional polypropylene–styrene–divinylbenzene-based ion exchange fibers, the synthesis strategy of PPS-based strong acid ion exchange fiber avoided the complicated irradiation grafting process with 60Co or other radiation facilities. Owing to the existing of thioether (Ar―S―Ar) and sulfoxide (―SO―) unit in fibrous matrix, a super-equivalent adsorption phenomenon for Cu(II) ion was observed. The HO3S-BC-XDC-PPS fiber possessed high exchange capacity (≥3.0 mmol/g) and excellent thermostabilities, and the exchange capacity and desorption rate were not decreased after six adsorption desorption cycles. Copyright © 2014 John Wiley & Sons, Ltd.

Liquid adsorption of tobacco specific N-nitrosamines by zeolite and activated carbon

In order to control the tobacco specific nitrosamines (TSNA) pollution caused by smoking, liquid adsorption of TSNA in tobacco-extract solution by modified activated carbon, zeolites and other porous materials was systemically studied with the monitor of Liquid Chromatography–Tandem Mass Spectrometry (LC–MS/MS) technique. The effect of solid–liquid ratio, the porous structure and surface acidic-basicity of sorbent on the liquid adsorption was assessed. Among various activated carbon (AC) samples modified with acid soak, ion-exchange or impregnation, the impregnated sorbent ZnAC could remove 73% of the TSNA in the solution, offering a cost-effective candidate for potential industrial application. Zeolite CaA was also efficient to trap more than 40% of TSNA in tobacco solution, and the influence of cation on the adsorption of TSNA by zeolite and the possible selectivity for the components of TSNA such as NNN, NAT and NNK were carefully examined. Besides, the fabrication of optimal micro-environment for liquid adsorption of TSNA was explored.

The Oligomerisation of High Olefin Containing Hydrocarbon Fractions on Ion Exchange Resin Catalyst

Nowadays there is an increasingly important issue in refineries to increase the gasoline / middle distillate flexibility because of the ever-changing motor fuel demands. One possible way is to oligomerize light olefins (3-6 carbon atoms). There is a further advantage of the oligomerization technology that with the hydrogenation of the olefin-isoolefin mixture, formed as an intermediate product, high paraffin-isoparaffin containing products can be produced. In our experimental work we investigated the conversion possibilities with oligomerization of the C4-C6 olefin content of light FCC and more fractions with different composition on acidic ion exchange resin catalyst. The favourable application temperature of the ion exchange catalyst was 120-130 °C (P= 30 bar, LHSV= 1.0 h -1 ). The available olefin conversion was also influenced by the composition of the feedstock. We achieved the best olefin conversion in the case of the feedstock with highest olefin content (olefin conversion: 91.5 %, C12+ selectivity: 31.2 %).

Bifunctional Tandem Catalysis on Multilamellar Organic–Inorganic Hybrid Zeolites

Tandem catalysis has been realized on the multilayered zeolites with organic-structure-directing agent (OSDA) molecules occluded within micropores. A combination of mild acid treatment and ion-exchange with ammonia solution was carried out on as-synthesized multilamellar MFI aluminosilicate, giving rise to an acid–base bifunctional catalyst. Containing tripropyl head groups, the Gemini-type quaternary ammonium OSDAs were firmly immobilized in the intersection of straight and sinusoidal 10-membered ring channels, with the other one exposed to the layer surface of the nanosheets. The resulting organic–inorganic materials possessed simultaneously the acid sites related to the framework Al and the base sites derived from coexisting OSDAs. In particular, two types of base sites were present, that is, the Lewis base sites due to the SiO– species and Brønsted base sites due to the OH– counteranion of exposed quaternary ammonium cations. The rigid materials were highly active and reusable in the one-pot reaction of tandem deacetalization–Knoevenagel condensation. Supporting palladium nanoparticles (Pd NPs) on the organic–inorganic hybrid zeolite led to bifunctional catalysts, which catalyzed effectively one-pot synthesis of benzylidene malononitrile from benzyl alcohol under soluble-base-free conditions, in which the benzyl alcohol was first aerobic oxidized to intermediate benzaldehyde followed by Knoevenagel condensation with malononitrile.

Degradative solvent extraction of demineralized and ion-exchanged low-rank coals

Dehydration and upgrading are essential pretreatment methods for efficient utilization of low-rank coal. In previous works the authors employed degradative solvent extraction method to dehydrate and upgrade low-rank coals and fractionate them into several fractions. For further study of this method, two low-rank coals (MM and LY) were pretreated by acid washing for demineralization or acid washing and Na/Co ion-exchange. The pretreated and raw coals were then extracted by 1-methylnaphthalene (1-MN) at 350°C and fractionated into upgraded coal (UC), high molecular weight extract (deposit), low molecular weight extract (soluble), as well as a little H2O and gas products. The results show that both acid washing and ion-exchange enhance the yields and carbon contents of the two extracts. Ion-exchange obviously promotes the removal of oxygen-containing functional group during extraction. The yield of high molecular weight extract of demineralized MM increases from 3.5% to 9.5%, and the carbon content and oxygen content of low molecular weight extract of Na ion-exchanged LY are as high as 85.3% and less than 6.4%, respectively. Ion-exchange has a distinct influence on physical and chemical properties of the extracts. The influence of Na ion-exchange is especially remarkable. Thus, demineralization and ion-exchange have evident promotion for the degradative solvent extraction of low-rank coal.

Three-dimensional graphene networks as a new substrate for immobilization of laccase and dopamine and its application in glucose/O2 biofuel cell.

We report here three-dimensional graphene networks (3D-GNs) as a novel substrate for the immobilization of laccase (Lac) and dopamine (DA) and its application in glucose/O2 biofuel cell. 3D-GNs were synthesized with an Ni(2+)-exchange/KOH activation combination method using a 732-type sulfonic acid ion-exchange resin as the carbon precursor. The 3D-GNs exhibited an interconnected network structure and a high specific surface area. DA was noncovalently functionalized on the surface of 3D-GNs with 3,4,9,10-perylene tetracarboxylic acid (PTCA) as a bridge and used as a novel immobilized mediating system for Lac-based bioelectrocatalytic reduction of oxygen. The 3D-GNs-PTCA-DA nanocomposite modified glassy carbon electrode (GCE) showed stable and well-defined redox current peaks for the catechol/o-quinone redox couple. Due to the mediated electron transfer by the 3D-GNs-PTCA-DA nanocomposite, the Nafion/Lac/3D-GNs-PTCA-DA/GCE exhibited high catalytic activity for oxygen reduction. The 3D-GNs are proven to be a better substrate for Lac and its mediator immobilization than 2D graphene nanosheets (2D-GNs) due to the interconnected network structure and high specific surface area of 3D-GNs. A glucose/O2 fuel cell using Nafion/Lac/3D-GNs-PTCA-DA/GCE as the cathode and Nafion/glucose oxidase/ferrocence/3D-GNs/GCE as the anode can output a maximum power density of 112 μW cm(-2) and a short-circuit current density of 0.96 mA cm(-2). This work may be helpful for exploiting the popular 3D-GNs as an efficient electrode material for many other biotechnology applications.

Application of High-Efficiency Reverse Osmosis Technology in Reclaimed Water Treatment in Power Plants

Because of the poor quality of the operational water (urban reclaimed water) of one power plant in Hebei, China, a high-efficiency reverse osmosis (HERO) system with foreign patents is utilized for advanced treatment of the reclaimed water. The influence of the main factors (including the alkalinity and the suspended solid content of the feed water, the flux, and the pH of the concentrated water) on the performance of the HERO system were studied. The high alkalinity (high concentration of carbonate) of the feed water resulted in HERO scaling, and the low alkalinity caused the penetration of hardness through the weak acid ion exchangers and, therefore, also caused HERO scaling. The high suspended solid content of the feed water caused rapid decrease in the product flux of HERO. The low concentrated water flux also decreased the product flux. As the pH of the concentrated water became higher, the stability of the HERO operation increased. Based on the pH endurance of the membranes and the characteristic of the high-pH operation of the HERO system, the water production was basically stable when the pH of the concentrated water lay between 10.5 and 10.8. Affected by the ammonia in the reclaimed water, the pH of the product water was higher than that of the feed water. The pH of the feed water was higher than that of the concentrated water. When the pH of the concentrated water was above 10.8, the pH values were close to one another. The results of the chemical cleaning experiments indicated that hardness, phosphorus, ammonia, silicon dioxide, and iron ions were the main influencing chemical factors of HERO, in which the former three formed a sediment of magnesium ammonium phosphate, and the latter two formed an iron silicate sediment.