Acid Cation Exchange Research Articles

SINTESIS DAN PERBANDINGAN STRUKTUR, TEKSTUR BENTONIT ALAM DAN BENTONIT TERAKTIVASI ASAM

Bentonite is a material that has several layers, which consists of one layer of octahedral and two tetrahedral layers or commonly known as the bentonite mineral that is composed of layers of 2: 1. Bentonite nature in general is less than optimal when used as an adsorbent. This can be overcome by activating the natural bentonite either chemistry or physics. In this study, natural bentonite acid activated. Bentonite activated with HF acid with a variety of 1% -5%. Acid can damage the structure of octahedral layers in the space between the layers. Effect of activation with HF acid cause ion exchange of Al3+, Fe3+, Mg2+ with H+ ions from the acid HF so changes smectite crystalline structures. Activation of bentonite with lead acid cation exchange capacity decreased and significantly increases the specific surface area of 26.893 m2 / g (natural bentonite) to 43.167 m2 / g (activated).

Removal of Radium from Synthetic Shale Gas Brines by Ion Exchange Resin

Abstract Rapid development of hydraulic fracturing for natural gas production from shale reservoirs presents a significant challenge related to the management of the high-salinity wastewaters that return to the surface. In addition to high total dissolved solids (TDS), shale gas-produced brines typically contain elevated concentrations of radium (Ra), which must be treated properly to prevent contamination of surface waters and allow for safe disposal or reuse of produced water. Treatment strategies that isolate radium in the lowest volume waste streams would be desirable to reduce disposal cost and generate useful treatment by-products. The present study evaluates the potential of a commercial strong acid cation exchange resin for removing Ra2+ from high-TDS brines using fixed-bed column reactors. Column reactors were operated with varying brine chemistries and salinities in an effort to find optimal conditions for Ra2+ removal through ion exchange. To overcome competing divalent cations present in the b...

Furfural based policondensation type sulfonic acid cation-exchange resin

Furfural based policondensation type sulfonic acid cation-exchange resin

Prewashing enhances the liquid hot water pretreatment efficiency of waste wheat straw with high free ash content

The effect of prewashing process prior to the liquid hot water (LHW) pretreatment of high free ash content waste wheat straw (WWS) was investigated. It was found that prewashing process decreased the ash content of WWS greatly, from 29.48% to 9.82%. This contributed to the lower pH value of prehydrolyzate and higher xylan removal in the following LHW pretreatment. More importantly, the prewashing process effectively increased the cellulose enzymatic hydrolysis efficiency of pretreated WWS, from 53.04% to 84.15%. The acid buffering capacity (ABC) and cation exchange capacity (CEC) of raw and prewashed WWS were examined. The majority of free ash removal from WWS by prewashing resulted in the decrease of the ABC of the WWS from 211.74 to 61.81mmol/pH-kg, and potentially enhancing the efficiency of the follow-up LHW pretreatment.

Kinetic and Reactive Distillation for Acrylic Acid Synthesis via Transesterification

Reaction distillation was first used for the process of acrylic acid synthesis through transesterification of methyl acrylate with acetic acid using a strongly acidic cationic exchange resin catalyst (NKC-9). Pseudo-homogeneous (P-H) and Langmuir–Hinshelwood (L-H) heterogeneous kinetic models were presented and fitted with the experimental data obtained from the batch reaction. The key factors of the heterogeneous kinetic model were the four components’ adsorption equilibrium constants on the catalyst surface, and they were determined by adsorption experiments. The activity coefficients were calculated using the NRTL method. The catalyst stability was evaluated in a fixed-bed reactor. Catalyst activity showed no obvious decrease after 1000 h of running. A reactive distillation column for acrylic acid synthesis was proposed and designed with process simulation.

Modified DIX model for ion-exchange equilibrium of l-phenylalanine on a strong cation-exchange resin

L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of l-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of l-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange (DIX) model, which takes the activity into account, was established to predict the uptake of l-phenylalanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest l-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.

Preparation of poly(glycidylmethacrylate-divinylbenzene) weak acid cation exchange stationary phases with succinic anhydride, phthalic anhydride, and maleic anhydride for ion chromatography.

In this work, poly(glycidylmethacrylate-divinylbenzene) microspheres were prepared and applied for the preparation of weak acid cation exchange stationary phases. Succinic anhydride, phthalic anhydride, and maleic anhydride were selected as carboxylation reagents to prepare three weak acid cation exchangers by direct chemical derivatization reaction without solvent or catalyst. The diameters and dispersity of the microspheres were characterized by scanning electron microscopy; the amount of accessible epoxy groups and mechanical stability were also measured. The weak acid cation exchangers were characterized by Fourier transform infrared spectroscopy; the content of carboxyl groups was measured by traditional acid base titration method. The chromatographic properties were characterized and compared by separating alkali, alkaline earth metal ions and ammonium and polar amines. The separation properties enhanced in the order of succinic anhydride, phthalic anhydride, and maleic anhydride modified poly(glycidylmethacrylate-divinylbenzene) cation exchangers.

Weak Base Diffusion in Strong Acid Cation Exchangers

ABSTRACTThe gel diffusion kinetics of ion exchange on strong acid cation exchangers with the participation of a weak base is considered. The kinetics of benzocaine desorption from sulfonated polycalixarene and CU-23 30/100 sulfocationite has been experimentally studied. It is found that the diffusion coefficient of cations of protonated benzocaine is (1.21 ± 0.23) ∙10−12 m2/s in CU-23 30/100 sulfocationite and (0.65 ± 0.06) ∙10−13 m2/s in sulfonated polycalixarene. The diffusion coefficient of nonionized benzocaine molecules is (0.65 ± 0.15) ∙10−14 m2/s in sulfonated polycalixarene. The model of the pharmacokinetic behavior of benzocaine immobilized in sulfocationite is presented.

Selective Synthesis of Vinyl‐ or Alkynyl Chalcogenides from Glycerol and their Water‐Soluble Derivatives

AbstractWe describe here a convenient procedure to synthesize new vinyl chalcogenides in the reaction of dichalcogenides derived from glycerol with terminal alkynes and NaBH4, where polyethylene glycol‐400 (PEG‐400) is the solvent at 30 °C in a N2 atmosphere. In addition, we report an interesting result for the synthesis of alkynyl chalcogenides using the same substrates with EtOH as the solvent. In both protocols, the corresponding products were obtained in good yields with high selectivity and tolerated a range of terminal alkynes. The treatment of these compounds with acidic cation exchange resin Dowex‐(H+) produced new water‐soluble organochalcogen compounds.

Adsorption thermodynamics and kinetics of yohimbine onto strong acid cation exchange fiber

Abstract The strong acidic cationic exchange fiber (SACEF) was used to adsorb yohimbine from alcoholic solution. Batch experiments were performed to examine the effects of adsorbent dosage, solution pH and temperature in the adsorption process. The thermodynamics and kinetics of adsorption were also analyzed. The optimum yohimbine adsorption onto the SACEF was found at pH = 5 of solution and equilibrium could be attained within 20 min. The equilibrium adsorption data were preferably modeled with the Freundlich isotherm model and the thermodynamic parameters were calculated to be: 11.99 kJ/mol

Evaluation of chelate and cation exchange resins to remove copper ions

Copper ion (Cu2+) removal from aqueous solutions was performed with two different chelating resins (bis-picolylamine, iminodiacetate). In order to compare the results obtained from the chelating resins, strong acid cation exchangers were used with sulfonic acid functionally. The effects of the following parameters such as the amount of resin, the duration, pH levels and concentration were noted for the ion-exchange. The Langmuir, Freundlich, D-R and Scatchard isotherm models were used to evaluate the data. The Langmuir isotherm model was found to be the best model. The chelating resins which retained some of their functional groups showed good properties for the removal of Cu2+ from aqueous solutions. The sorption capacity of the resins increased with the rising Cu2+ concentration in the aqueous medium. FT-IR analysis results show clearly that the ion-exchange and chelating took place as mechanisms which rule during the sorption of Cu2+ from aqueous phase.

Effect of competing amines on the removal of tetramethylammonium hydroxide from solution using ion exchange.

Tetramethylammonium hydroxide (TMAH, TMA(+)) has been widely used as the photoresist developer in semiconductor and thin film transistor liquid crystal display manufacturing. In this study, TMAH-containing wastewater was treated by ion exchange method. Strong acid cation exchange resin was used. A kinetics study revealed that the ion exchange reaction reached equilibrium within 20 min and it could be described by a pseudo-second-order model. To assess the effects of competing ions, wastewater was spiked with three different amines, namely ethylamine (EA(+)), diethylamine (DEA(+)), and triethylamine (TEA(+)). TMAH uptake decreased when in the presence of amines, and it decreased in the order EA(+) < DEA(+) < TEA(+). It could be attributed to different proton affinity (PA) and the strength of affinity between amine molecules and resin matrix, as found from the ab initio calculation values and Langmuir isotherm parameters. However, the interaction energy between sulphonic acid groups and interfering amines in solution using density functional theory (DFT) calculation resulted in a different trend compared with that of PA. The difference might be caused by stabilization of amines by resin matrix and different molecular structures.

Performance of ion exchange resin as solid catalyst for the esterification of acetic acid with ethanol

Esterification of acetic acid with ethyl alcohol was carried out in the presence of a cation exchange resin. The resin used was Lewatit S1467, which is commercially available at a low cost and used commonly in the water treatment industry. The catalyst pretreated with HCl showed higher acetic acid conversions. The acidic cation exchange resin treated with HCl was examined for catalyst loading, reaction temperature and reusability. The highest acetic acid conversion of 58 % was observed for acetic acid to ethanol mole ratio of 1:1 at 335 K with a 5.4 % (w/w) catalyst loading. The experimental data were fitted with the pseudo homogeneous model, and the heterogeneous models Langmuir-Hinshelwood (LH) and Eley- Rideal (ER). LH model provided a better agreement with the experimental kinetic data, and the activation energy was found to be about 58 kJmol-1.

Isolation of fructose from high‐fructose corn syrup with calcium immobilized strong acid cation exchanger: Isotherms, kinetics, and fixed‐bed chromatography study

AbstractIn this work, a separation strategy for fructose purification from high‐fructose corn syrup (HFCS) was established, involving two consecutive instances of chromatography with Ca2+‐immobilized cation exchanger XA 2004/22. Among the 14 calcium ion form of strong acid cation exchangers tested, cation exchanger XA 2004/22 displayed the best adsorption performances for fructose, with the adsorption ratio of fructose to glucose reaching 2.32 at 303 K. The static equilibrium adsorption data of fructose on Ca2+‐immobilized cation exchanger XA 2004/22 closely fitted the linear equation, and the adsorption kinetic followed the pseudo‐second order model. Close agreement between the theoretical curves and the experimental breakthrough data was observed using the Thomas and Yoon‐Nelson models. Under the optimized conditions, fructose was prepared at a purity of 0.924 g/g (92.4 mass %) and 0.243 g/g (24.3 mass %) yield by two‐step packed bed chromatography with Ca2+‐immobilized cation exchanger XA 2004/22. Further introducing one step of simple cooling crystallization gave crystalline fructose at 0.99 g/g (99 mass %) purity.

Etherification of Glycerol with Ethanol over Solid Acid Catalysts: Kinetic Study Using Cation Exchange Resin

The etherification of glycerol with ethanol is a novel process to utilise low-value by-product (glycerol) of the biodiesel industry to produce ethers of glycerol suitable for use as fuel additive or solvent. The etherification of glycerol with ethanol was investigated under the liquid phase in a high pressure batch reactor using two different types of commercial solid acid catalyst (zeolites and strongly acidic cation exchange resin (CER)). The CER showed superior catalytic activity over H-beta zeolite. The diethyl ether was observed as major product at high ethanol-to-glycerol mole ratio. The product selectivity diverted towards ethers of glycerol with decreasing ethanol-to-glycerol mole ratio. Among ethers of glycerol, glycerol monoethyl ether was the major product of the reaction. The reaction mechanism for etherification of glycerol with ethanol was delineated based on experimental observations. The reaction rate increased with increasing catalyst loading and temperature without affecting selectivity to the products significantly. The apparent activation energy of glycerol and ethanol was 25.1 and 26.6 kcal/mol, respectively. An empirical kinetic model was developed to correlate experimental data at different temperatures. The conversion of the reactants calculated from the kinetic model matched reasonably with experimental data.

Removal of 134Cs and 152+154Eu from liquid radioactive waste using Dowex HCR-S/S

Abstract Radionuclides should be separated from the waste streams before their discharge due to their undesired effects on human physiology and ecological systems. In this work, the feasibility of using Dowex-HCR-S/S(HCR), a strong acid cation-exchange resin as sorbent for 134Cs and 152+154Eu ions removal was examined. Sorption experimental data were analyzed by kinetic and isotherm models. The distribution coefficients of 134Cs and 152+154Eu were studied as a function of pH; 3525.6 mL/g and 393.1 mL/g were obtained in case of 152+154Eu and 134Cs at pH 4.1, respectively. Four isotherm models; Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich, were used to fit the sorption equilibrium data. The results indicated that the sorption of both 134Cs and 152+154Eu onto HCR resin is highly fit with the pseudo-second order model. The sorption kinetic for 134Cs and 152+154Eu onto polymeric resin takes 90 and 120 min to reach equilibrium which is considered as a fast kinetic process. The results of sorption experiments indicate that the maximum sorption capacity of 134Cs and 152+154Eu are 102.84 and 161.93 mg/g. The amount of radionuclides removed increased with increasing temperature, which indicates the endothermic nature of the sorption process. The negative values of ΔG ○ indicated the spontaneity of the sorption process. The proposed procedure has been successfully applied for the removal of 134Cs, 152+154Eu and other radionuclides from real liquid radioactive waste. The present study concludes that the commercial HCR resin used under these conditions, has a considerable potential as an effective sorbent for the removal of 134Cs and 152+154Eu from real radioactive wastewater. It can therefore have a place in the treatment of cationic radionuclides from radioactive wastewater since it is of a low-cost and commercially available adsorbent.

ケナフを材料とした弱酸性型陽イオン交換体の合成とその銅（II）及び白金族金属イオン吸着特性

ケナフを材料とした弱酸性型陽イオン交換体の合成とその銅（II）及び白金族金属イオン吸着特性

Esters of ricebran oil with short chain alcohols as alternative fuel for diesel engines

The potential of ricebran oil as a feedstock for the production of a fuel for diesel engines alternative to regular diesel fuel has been assessed. Esterification rate of crude ricebran oil with methyl alcohol was studied using different volumetric ratios of alcohol to oil, different catalyst loads and catalyst types. Catalysts used were sulfuric acid at a concentration of 2% of the oil/alcohol mixture in addition to hydrochloric acid and Amberlite IR-120 cation exchange resin at the same molar concentration of H+ as in case of sulfuric acid. The reaction was fastest using sulfuric acid which has been then used to prepare esters of ricebran oil with methyl, ethyl, propyl and butyl alcohols. The four products have been evaluated as a fuel for diesel engines according to their fuel properties compared to regular diesel fuel. These properties include the calorific value, flash point, viscosity, pour point, cetane number, sulfur content and ASTM distillation characteristics. The results have shown that the methyl as well as the ethyl esters have the closest properties to those of regular diesel fuel. Diesel engine performance using blends of regular diesel fuel with methyl and ethyl esters of ricebran oil have been tested and compared to that using regular diesel fuel. The results have shown that the engine performance using a blend of 50% regular diesel fuel and 50% methyl esters of ricebran oil is better than that using regular diesel fuel. The brake thermal efficiency at full load was 30.2% using the fuel blend compared to 27.5% in case of regular fuel.

Identification and characterization of a novel antioxidant peptide from feather keratin hydrolysate.

To improve the potential value of feather, which is a valuable protein resource, we have separated and identified antioxidant peptide(s) from feather hydrolysate. Feather hydrolysate was prepared by fermentation with Bacillus subtilis S1-4. Antioxidative peptides were separated by sequential acid precipitation, cation exchange, and reversed-phase fast performance liquid chromatography. Finally, a peptide with antioxidative activity was identified as Ser-Asn-Leu-Cys-Arg-Pro-Cys-Gly by MALDI time-of-flight (TOF)/TOF analysis, and determined to represent a portion of feather keratin near its N-terminal. A synthesized peptide with the same sequence was used to characterize its antioxidative properties, including scavenging free radicals, reducing power, and Fe(2+) chelation. In terms of the peptide's amino acid composition, the antioxidative activity might be mainly attributed to Cys and other amino acid residues. Feather keratin is a good source for the quantitative preparation of antioxidative peptides.

Synthesis, characterization and analytical application of polyaniline tin(IV) molybdophosphate composite with nanocrystalline domains

Polyaniline–tin(IV)molybdophosphate nanocomposite has been synthesized by incorporating polyaniline into inorganic exchanger tin(IV)molybdophosphate. Simultaneous TGA–DTA, FTIR, XRD, HRTEM and EDS have been used to characterize this composite material. The polyaniline–tin(IV)molybdophosphate (PATMP) behaves as bifunctional and strong acid cation exchanger with IEC of 1.79meqg−1 for Na+ ions. Thermal analysis of the material shows that the material retains 75% of its ion-exchange capacity up to 600°C. Adsorption behavior of metal ions in different solvents with varying concentration has also been explored. The sorption studies revealed that the material is selective for Pb(II) and Cu(II) ions. The analytical utility of the material has been explored by achieving some binary separations of metal ions on its column based on the distribution coefficients. Pb(II) and Cu(II) have been selectively removed from synthetic mixtures of Pb(II)–Mn(II), Pb(II)–Ni(II), Cu(II)–Mn(II) and Cu(II)–Ni(II).