Presence Of Cation Exchange Resin Research Articles

ENHANCING COPPER REMOVAL THROUGH INTEGRATED CAPACITIVE DEIONIZATION WITH HETEROGENEOUS CATION EXCHANGE MEMBRANE

Capacitive deionization (CDI) is a novel technique to eliminate ions present in the solution. This study was designed to evaluate the impact of cation exchange resin loading on the membrane using the nonsolvent-induced phase inversion method. After optimizing the resin loading on the membrane, the prepared membrane was employed for the membrane capacitive deionization (MCDI). A concentration of 500 mg.L-1 Cu2+ was used as a test contaminant in the CDI system to study Cu2+ removal and recovery at different voltages. Results showed that resin loading substantially influenced the membrane structure and enhanced the Cu2+ removal by the CDI technique. The presence of cation exchange resin on the membrane was found by the appearance of a peak at 1,007 cm-1, 1,035 cm-1, and 1,128 cm-1 in the FTIR spectra of the –SO3 group, which became more significant as the amount of resin increased. The prepared membrane’s water uptake and ion exchange capacity increased as the quantity of resins loaded onto the membrane increased. When monitoring a current-time graph during CDI tests, an adsorption amount of 6.9 mg.g-1 of Cu2+ and recovery efficiency of 51.7 % at the 10th cycle in the MCDI cell was observed for M20 (20% by wt resin). Using the prepared membrane in the CDI system has the potential to remove Cu2+ from the solution selectively.

Organic binding iron formation and its mitigation in cation exchange resin assisted anaerobic digestion of chemically enhanced primary sedimentation sludge

Fe based chemically enhanced primary sedimentation (CEPS) is an effective method of capturing the colloidal particles and inorganic phosphorous (P) from wastewater but also produces Fe-CEPS sludge. Anaerobic digestion is recommended to treat the sludge for energy and phosphorus recovery. However, the aggregated sludge flocs caused by the coagulation limited sludge hydrolysis and P release during anaerobic digestion process. In this study, cation exchange resin (CER) was employed during anaerobic digestion of Fe-CEPS sludge with aims of prompting P release and carbon recovery. CER addition effectively dispersed the sludge flocs. However, the greater dispersion of sludge flocs could not translate to higher sludge hydrolysis. The maximum hydrolysis and acidification achieved at lower CER dosage of 0.5 g CER/g TS. It was observed that the extents of sludge hydrolysis and acidification had a strongly negative correlation with the organic binding iron (OBI) concentration. The presence of CER during anaerobic digestion favored Fe(III) reduction to Fe(II), and then further induced iron phase transformation, leading to the OBI formation from the released organic matters. Meanwhile, higher CER dosage resulted in higher P release efficiency and the maximum efficiency at 4 g CER/g TS was four times than that of the control. The reduction of BD-P, NaOH-P and HCl-P in solid phase contributed most P release into the supernatant. A new two-stage treatment process was further developed to immigrate the OBI formation and improve the carbon recovery efficiency. Through this process, approximately 45% of P was released, and 63% of carbon was recovered as methane from Fe-CEPS sludge via CER pretreatment.

ТРАНСЕСТЕРИФІКАЦІЯ ТРИГЛІЦЕРИДІВ СОНЯШНИКОВОЇ ОЛІЇ АЛІФАТИЧНИМИ СПИРТАМИ С1–С4

Transesterification of sunflower oil triglycerides by C1-C4 aliphatic alcohols in the presence of cation exchange resin KU-2-8 with immobilized divalent metal ions has been studied. It was found that the reaction occurs at a high initial rate and the conversion of triglycerides for 180 min in presence aliphatic alcohols C1– C3 is 88.4-99.8 %. It is shown that under these conditions the rate of transesterification reaction of triglycerides with butan-1-ol is significantly lower and the conversion achieved in 180 min does not exceed 52.3 %.

Esterification of unsaturated fatty acids by the fusel oil alcohols

The aim of the research was to determine the regularities for esterification process of an unsaturated fatty acids by the fusel oil alcohols, including by individual 2-methylpropan-1-ol and 3-methylbutan-1-ol. As catalysts for esterification process the cation exchange resin KU-2-8 and the p-toluenesulfonic acid were used. It was established that during the esterification process of an unsaturated fatty acids by 3-methylbutan-1-ol in the presence of p-toluenesulfonic acid the acids conversion in 40 minutes of the reaction reaches 95.1 %, while in the presence of cation exchange resin it reaches 92.6 % for 300 minutes. Under these same conditions an unsaturated fatty acids conversion for esterification reaction with 2-methylpropan-1-ol in the presence of cation exchange resin KU-2-8 reaches only 78.9 % in 300 min. The use of benzene which forms a triple benzene-alcohol-water azeotropic mixture has a different effect on the achieved equilibrium conversion of acids when they interact with 2-methylpropane-1-ol and fusel oil. The maximum effect of the use of benzene is achieved in the esterification process of an unsaturated fatty acids by fusel oil in the presence of cation exchange resin KU-2-8: maximum conversion of unsaturated fatty acids is 83.2 %. In the absence of benzene it reaches only 22.6 %. Extreme dependence of an unsaturated fatty acids conversion on the reagents ratio was found. It is explained by the fact that in the presence of a high fusel oil excess the quotient of water-soluble alcohols increases. It worsens the drainage of water from the reactor and results in a low an unsaturated fatty acids conversion. The low value of the acids conversion by a small surplus of fusel oil is due to a decrease in the proportion of C2–C3 alcohols, which are also involved in the esterification process of an unsaturated fatty acids and are more reactive than higher alcohols. The accomplished studies show the expedience of using as a raw material for the production of esters of higher fatty acids of such substances as an unsaturated fatty acids (sunflover oil waste products) and fusel oil (waste of ethyl alcohol production) or of individual C4–C5 alcohols.

Desorption kinetics of cesium from Fukushima soils

Understanding the behaviors of Cs+ in soils is crucial for evaluation of the impacts of disposal of soils contaminated by radiocesium, 137Cs. The desorption rate of Cs+ evaluated in relatively short periods of time may not be adequate for such a purpose. In this study, we investigated long-term desorption kinetics of 137Cs and 133Cs from soils collected in Fukushima Prefecture by batch desorption experiments in the presence of cation exchange resin as a sorbent. The sorbent can keep the concentration of Cs+ in the aqueous phase low and prevent re-sorption of desorbed Cs+. Up to 60% of 137Cs was desorbed after 139 d in dilute KCl media, which was larger than the desorption by conventional short-term extraction with 1 M ammonium acetate. Desorption of 137Cs continued even after this period. It was also found that high concentration of K+ prevented desorption of Cs+ in the initial stage of desorption, but the effect was alleviated with time. The desorbed fraction of stable Cs was smaller than that of 137Cs. This indicated that 137Cs may gradually move to more stable states in soils. The half-life of 137Cs desorption from the slowest sorption site was estimated to be at least two years by a three-site desorption model.

Esterification of fusel oil using reactive distillation – Part I: Reaction kinetics

Fusel oil is a mixture of C2–C5 alcohols such as ethanol, n-propanol, iso-butanol and iso-amyl alcohol. It is expected that reactive distillation (RD), which is a proven intensification strategy for esterification of individual alcohols can also be a promising option for simultaneous esterification of all the alcohols in fusel oil. To evaluate its feasibility and design a unit on large scale, kinetic and phase equilibrium models are necessary. In this work, we experimentally investigate reaction kinetics for all the esterification and trans-esterification reactions of the different constituents of fusel oil with acetic acid. The reactions are performed in the presence of cation exchange resin, Amberlyst-15, in a batch reactor over a wide range of parameters such as temperature, mole ratio and catalyst loading. A unified Langmuir–Hinshelwood–Hougen–Watson (LHHW) model is proposed for the reacting system consisting of all the alcohols and the experimental data is used to estimate the model parameters. The predictions are in line with the experimental data for individual alcohols as well as their mixtures. A feasible process based on reactive distillation is simulated in ASPEN PLUS using the kinetics developed in this work.

Crystal and molecular structure of methyl l-glycero-α-d-manno-heptopyranoside, and synthesis of 1→7 linked l-glycero-d-manno-heptobiose and its methyl α-glycoside

Methyl l-glycero-α-d-manno-heptopyranoside was synthesized in good yield by a Fischer-type glycosylation of the heptopyranose with methanol in the presence of cation-exchange resin under reflux and microwave conditions, respectively. The compound crystallized from 2-propanol in an orthorhombic lattice of space group P21212 showing a comparatively porous structure with a 2-dimensional O–H⋯O hydrogen bond network. As model compounds for the side chain domains of the inner core structure of bacterial lipopolysaccharide, l-glycero-α-d-manno-heptopyranosyl-(1→7)-l-glycero-d-manno-heptopyranose and the corresponding disaccharide methyl α-glycoside were prepared. The former compound was generated via glycosylation of a benzyl 5,6-dideoxy-hept-5-enofuranoside intermediate followed by catalytic osmylation and deprotection. The latter disaccharide was efficiently synthesized in good yield by a straightforward coupling of an acetylated N-phenyltrifluoroacetimidate heptopyranosyl donor to a methyl 2,3,4,6-tetra-O-acetyl heptopyranoside acceptor derivative followed by Zemplén deacetylation.

Styrylation of phenol in the presence of cation-exchange resins. Influence of the product composition on its stabilizing performance in rubber

Methylbenzylated phenols were prepared by catalytic reaction of phenol with styrenes. The effect of a series of cation-exchange resins on the product composition was examined, and the stabilizing performance of the products in rubber was evaluated.

Calcium oxide as a solid base catalyst for transesterification of soybean oil and its application to biodiesel production

In order to study solid base catalyst for biodiesel production with environmental benignity, transesterification of edible soybean oil with refluxing methanol was carried out in the presence of calcium oxide (CaO), -hydroxide (Ca(OH)2), or -carbonate (CaCO3). At 1 h of reaction time, yield of FAME was 93% for CaO, 12% for Ca(OH)2, and 0% for CaCO3. Under the same reacting condition, sodium hydroxide with the homogeneous catalysis brought about the complete conversion into FAME. Also, CaO was used for the further tests transesterifying waste cooking oil (WCO) with acid value of 5.1 mg-KOH/g. The yield of FAME was above 99% at 2 h of reaction time, but a portion of catalyst changed into calcium soap by reacting with free fatty acids included in WCO at initial stage of the transesterification. Owing to the neutralizing reaction of the catalyst, concentration of calcium in FAME increased from 187 ppm to 3065 ppm. By processing WCO at reflux of methanol in the presence of cation-exchange resin, only the free fatty acids could be converted into FAME. The transesterification of the processed WCO with acid value of 0.3 mg-KOH/g resulted in the production of FAME including calcium of 565 ppm.

Esterification of Lactic Acid with n-Butanol by Reactive Distillation

Esterification of lactic acid with n-butanol may be performed to synthesize n-butyl lactate or to recover lactic acid from its aqueous solution. In the present work, the reaction is performed in the presence of cation-exchange resins as a catalyst. Kinetic parameters like activation energy and the rate constants are estimated using the pseudohomogeneous model. The applicability of reactive distillation for this reaction is evaluated through experiments using batch and continuous reactive distillation techniques. An equilibrium stage model is formulated, and simulation results are compared with the experimental results. Further, the effects of operating parameters like feed mole ratio, catalyst loading, and boilup rate are evaluated on the conversion of lactic acid in batch reactive distillation. Experimental results of continuous reactive distillation are compared with the simulation results observed using the Aspen plus process simulator. Effects of operating variables were studied with the help of the e...

Hydration of Dicyclopentadiene in the Presence of Cation Exchange Resin

In the present work the hydration of dicyclopentadiene (DCPD) has been studied in the presence of cation exchange resin catalyst. Ion exchange resin Amberlyst-15 was found to offer the best performance with more than 95% selectivity toward cydecanol and conversion as high as 15%. The literature suggests that the zeolites are more active than ion exchange resin catalysts for such reactions. However, this is one of those few liquid phase hydrations for which ion exchange resins offer much better performance in terms of both rate and selectivity toward alcohol. An important finding of our earlier study on this reaction is that the properties of the ion exchange resin catalyst are modified during the course of reaction, which helps in improving the reaction kinetics. In the present work, the kinetic studies have been discussed in detail and issues such as catalyst reusability and reasons for the rate enhancement have been addressed.

Kinetics of esterification of propionic acid with n-amyl alcohol in the presence of cation exchange resins

Esterifications of n-amyl alcohol with propionic acid catalyzed by macroporous (Amberlyst-15) and microporous (Dowex 50 W and Amberlite IR-120) polymeric ion-exchange resins were carried out between 333–348 K. When these catalysts were used as commercially available, Amberlyst-15 was observed to be the most effective catalyst with respect to rate constants, but after drying it became the less effective one. The reaction rate increased with increase in catalyst concentration and reaction temperature. Stirrer speed and different mesh sizes had virtually no effect on the rate under the experimental conditions. The effect of divinylbenzene content was examined for the microporous resin Dowex 50W, and the results showed that the propionic acid conversion decreased as the divinylbenzene content was increased. The rate data were correlated with a second-order homogeneous reaction model. The apparent activation energies, reaction enthalpies and entropy values were calculated for each catalyst. Reaction monitoring is simple and fast by volumetric method and the reproducibility of this method was the order of ± %2.54.

Volumetric, Chromatographic, Refractometric Studies on the Esterification of Methanol with Acetic Acid in the Presence of Cation-Exchange Resins

Summary Esterification of methyl alcohol with acetic acid catalysed by commercially available polymeric ion-exchange resins Amberlyst-15, Dowex 50W and Amberlite IR-120 was carried out in the temperature ranging between 323–338K. Mesh sizes and divinylbenzene contents had virtually no effect on the rate the data of which were correlated with a second-order homogeneous reaction. The samples were analysed with gas chromatography, refractometry and volumetry. The reproducibilities were the order of ±2.89%, ±5.07% and the order of ±6.58% respectively for the volumetric, chromatographic and refractometric methods.

Resin-catalyzed hydrolysis of some esters in aqueous and non-aqueous mixtures

The catalytic hydrolysis of ethyl, butyl and isobutyl acetates in aqueous solution and aqueous organic mixtures in presence of cation exchange resin in the hydrogen form was studied. The acid resin, however, behaved in aqueous organic mixtures in the same way as such resins do in pure water. The order of the chemical reaction in the heterogeneous catalysis by the resin was found to be the same as in the homogenous catalysis by a dissolved electrolyte. This was considered to indicate that the reaction mechanism is essentially the same in both cases. The overall rate was controlled by the chemical reaction of the ester at the catalytically active sites within the resin. The activation parameters were calculated for all the investigated reactions.

Kinetics of Esterification of Lactic Acid with Methanol in the Presence of Cation Exchange Resin Using a Pseudo-Homogeneous Model.

The kinetics of esterification of lactic acid with methanol in the liquid phase are studied by using a cation exchange resin in the H+ form (DOWEX-50W) as an acid catalyst. Experiments were carried out in a stirred batch reactor at different temperatures (323, 333, 343, 353 K) under atmospheric pressure. The effects of reaction temperature and catalyst loading on the reaction rate are investigated. It is found that catalyst size and stirring speed have no significant effects on reaction rate. The reaction rate data are correlated with a kinetic model based on pseudo-homogeneous catalysis. The activity of resin is compared with that of sulfuric acid as a catalyst. A kinetic equation for describing the reaction catalyzed by cation exchange resin is developed.

Esterification of formic acid, acrylic acid and methacrylic acid with cyclohexene in batch and distillation column reactors: ion-exchange resins as catalysts

Esterification of formic acid, acrylic acid and methacrylic acid with cyclohexene was carried out in the presence of cation-exchange resins as catalysts. Effect of various parameters, e.g. speed of agitation, catalyst particle size, catalyst loading, types of catalyst, temperature, mole ratio of the reactants, was studied to optimise the reaction conditions. The reaction of formic acid, with different concentrations in aqueous solutions, with cyclohexene was studied. Experiments were carried out in the presence of homogeneous catalyst, p-toluene sulphonic acid ( p-TSA), to compare results with the heterogeneous catalyst. A comparison of anhydrous esterification between acrylic acid and that of methacrylic acid with cyclohexene has been reported. The conversion of formic acid in aqueous solutions to cyclohexyl formate, by reaction with cyclohexene, in a distillation column reactor (DCR), packed with an acidic ion-exchange resin catalyst was studied; the effect of variables such as feed flow rate, molar ratio of reactants, amount of catalyst in the reboiler, concentration of formic acid, location of the feed point, etc., was studied. A comparison between the rate of esterification of formic acid with cyclohexene in batch mode and in distillation column reactor has been made. An attempt was also made for the selective esterification of formic acid with cyclohexene from a mixture of formic acid and acetic acid in a DCR.

Removal of formaldehyde from aqueous solutions

The removal of formaldehyde from aqueous solutions of 2-butyne-1,4-diol (BD), which are prepared from ethynylation of acetylene with aqueous formaldehyde, was successfully accomplished by a number of approaches: reaction with sodium bisulfite and removal of the resultant ionic product with an anion exchange resin in a fixed bed system or using an anion exchange resin bed in bisulfite form; reactive distillation with methanol and ethylene glycol in the presence of cation exchange resin as catalyst to give the corresponding acetals; internal acetalization with BD in the presence of cation exchange resin as catalyst; Cannizzaro's reaction with sodium hydroxide; and aldol type condensation in the presence of sodium hydroxide. Residual concentrations of formaldehyde as low as 20 ppm could be achieved through more than one of the methods mentioned above.

A convenient method for the preparation of methyl ketones: acetylation of diisobutylene and diisoamylene with acetic anhydride in the presence of cation exchange resin and acid-treated clay as catalysts

Acetylation of diisobutylene and diisoamylene to form methyl ketones was carried out with acetic anhydride in the presence of cation exchange resin (Amberlyst-15) and acid-treated clay (Engelhard, F-24) as catalysts in the temperature range of 50–100°C. The effect of catalyst loading, temperature and mole ratio of olefin to acetic anhydride was studied. The overall rate of reaction increased with an increase in the catalyst loading, temperature and mole ratio of acetic anhydride to olefin. The kinetic data were analyzed using a heterogeneous model based on Rideal-Eley rate expressions. The values of apparent rate constants and activation energy are reported.

Alkylation of phenol with MTBE and other tert-butyl ethers: cation exchange resins as catalysts

Alkylation of phenol was carried out using methyl tert-butyl ether, mono tert-butyl ether of mono ethylene glycol, tert-butanol and isobutylene in the presence of cation exchange resins, acid treated clay and para-toluene sulfonic acid as catalysts. The selectivity with respect to 2- and 4-tert-butyl phenol was studied.

Esterification of acetic acid with styrene: Ion exchange resins as catalysts

Esterification of acetic acid with styrene was carried out in the presence of cation exchange resins as catalysts in the temperature range 20–60°C. The reaction was accompanied by dimerization of styrene. The selectivity with respect to the ester (1-phenylethyl acetate) was greatly influenced by the catalyst, solvent and operating conditions. Some experiments were carried out in the presence of homogeneous catalysts such as 98% H 2SO 4 and p-toluene sulfonic acid (PTSA) to find their utility for obtaining the ester. Optimum conditions for realising high selectivity with respect to the ester have been delineated. Monodisperse K2661 was found to be the best catalyst amongst those studied, in so far as the selectivity with respect to the ester was concerned.