Macroporous Cation Exchange Resin Research Articles

Adsorption Mechanisms of CO2 on Macroporous Ion-Exchange Resin Organic Amine Composite Materials by the Density Functional Theory.

The adsorption mechanisms of CO2 on macroporous cation exchange resin (MCER), D001 ion-exchange resin, and macroporous ion-exchange resin organic amine composite materials (MCER-DEA and D001-PEI) were studied by density functional theory (DFT). The adsorption energies and Mulliken atomic charges in the adsorption process were analyzed, indicating that CO2 on MCER and D001 were physisorbed. The adsorption heat of the adsorption process of MCER-DEA and D001-PEI was calculated by the Monte Carlo method, and it was found that the adsorption process of CO2 by MCER-DEA and D001-PEI was both physical adsorption and chemical adsorption. Besides, the chemical adsorption mechanism of CO2 by MCER-DEA and D001-PEI was investigated by analyzing the free energy barrier and the Gibbs free energy change of the involved chemical reactions and the results showed that the free energy barrier required for MCER-DEA to generate zwitterion was 26.23 kcal/mol, which is 1.74 times that of D001-PEI (15.04 kcal/mol); meanwhile, the free energy barriers of the deprotonation process of zwitterions in MCER-DEA and D001-PEI were 16.23 and 9.89 kcal/mol, respectively, indicating that D001-PEI chemically adsorbs CO2 and requires more energy than MCER-DEA chemical adsorption of CO2. D001-PEI is more conducive to the chemical adsorption of CO2. In addition, H2O molecules were incorporated on the polymer models to study the influence of humidity on the CO2 adsorption mechanism. The analysis revealed that the adsorption of CO2 slowed under humid conditions.

Preparation of CuO loaded cation exchange resin composites and its degradation of polyacrylamide aqueous solution

Macroporous cation exchange resins (CER) were used as carriers, and CuO loaded cation exchange resin composites was successfully prepared under thermostatic oscillation and hydrothermal conditions. The results showed that the as-prepared composites exhibited obvious shell-core structure. The different amounts of NaOH affected the micro morphology of CuO on the surface and in the internal pores of the resin, and also affected the percentage content of Cu element. XRD characterization clearly revealed that the products were monoclinic crystal system CuO species with a grain size of about 16 nm. The highest degradation rate of polyacrylamide (PAM) by CuO@IER-1g reached 81.94%, after 6 cycles CuO@CER-1g has still good photocatalytic activity, and the decrease in degradation rate was the combined effect from the adsorption of ion exchange resins and the electron-hole pairs formed by CuO and a series of free radical transfer reactions under ultraviolet light. This study has important theoretical basis and practical significance for enriching ion exchange theory, developing the photocatalytic industry, and purifying the environment.

Adsorption differences and mechanism of chitooligosaccharides with specific degree of polymerization on macroporous resins with different functional groups

Ion exchange resins are promising materials for separating chitooligosaccharides (COSs) with different degrees of polymerization (DP). The adsorbent functional groups significantly determine the interactions with COSs and affect their adsorption and separation efficiency. This study investigated the adsorption behaviors of COSs on macroporous cation exchange resins with different functional groups to clarify the functional group effect on the adsorption of COSs with different DP, which can also help to provide a theoretical basis for the selection of separation medium and optimization of the separation technics of COSs. The results showed that the adsorption of COSs on sulfonic-acid type resin DX-10 and carboxylic-acid type resin DC-10 were favorable, and the adsorption isotherms were in accord with the Sips model. Adsorption thermodynamics showed that temperature had opposite effects on the two resins' equilibrium adsorption capacity of COSs. The diffusion coefficient of COSs on DX-10 resin was greater, and the affinity gap between COSs on DX-10 resin was larger than that of DC-10 resin, which is beneficial for improving the separation resolution of COSs. In contrast, the interaction energy between COSs with high DP and DC-10 resin was weaker compared with DX-10, which made the elution of COSs with high DP easier.

Preparation of macroporous ion-exchange resin organic amine composite material by using waste plastics and its application in CO2 capture

ABSTRACT Two new types of solid adsorption material (macroporous cation exchange resin (MCER) and macroporous ion-exchange resin organic amine composite material (MCER-DEA)) were prepared from waste television plastics outer shell (WTPS) and used to capture CO2 in flue gas from coal-fired power plants. The results showed that the CO2 adsorption capacity of MCER-DEA was 2.87 mmol/g, while MCER was 1.87 mmol/g. The preparation mechanism and action mechanism of MCER and MCER-DEA was studied by Fourier transform infrared and quantum chemical calculations. The results showed that the electrophilic substitution occurs in between an H atom of meta position on the benzene ring and H2SO4. The electron energy of MCER-DEA was calculated to be 1.14 ev, indicating these MCERs formed acid–base coordination with diethanolamine (DEA). Besides, the electron energy of between MCER and CO2 was 0.27 ev, and the interaction force was dominated by hydrogen bonds. The electron energy of the MCER-DEA and CO2 was 3.02 ev, and the interaction force was mainly controlled by coordination bonds. It indicated that MCER and CO2 were primarily based on physical adsorption, while MCER-DEA and CO2 were mainly based on chemisorption adsorption. Adsorption kinetics studies showed that internal diffusion was a rate-controlling step.

A facile modification of cation exchange resin by nano-sized goethite for enhanced Cr(VI) removal from water

ABSTRACT A novel macroporous strong acidic cation exchange resin (D001) modified by nano-sized goethite (nFeOOH@D001) was fabricated by using a facile ethanol dispersion and impregnation method, and its efficiency for Cr(VI) removal was tested thereafter. Due to the dispersing effect of ethanol, FeOOH particles of 20–150 nm were coated on the D001 surfaces. The nFeOOH@D001 obtained a Cr(VI) removal efficiency and capacity of 80.2% and 7.4 mg/g respectively, 5 times and 8 times higher than that of the pristine D001. The Cr(VI) removal by nFeOOH@D001 followed the pseudo second-order kinetics and the Langmuir adsorption model. Column experiments also demonstrated that the nFeOOH@D001 exhibited a much better ability to remove Cr(VI) as compared to the D001. Additionally, the nFeOOH@D001 showed a potential for reusability and renewability. The adsorbed nFeOOH@D001 could be easily desorbed by 0.1 M acetic acid and a reuse efficiency of 92.7% could be maintained after 4 desorption–adsorption cycles. The used nFeOOH@D001 could be eluted by 0.1 M HCl to remove nFeOOH, and the renewed D001 could be recoated by nFeOOH and achieved a regeneration rate of 97.8% for Cr(VI) removal. The above results indicated that nano-sized goethite modification is a promising method to endow D001 with the ability to remove Cr(VI) from water.

Large-scale production of 88Y and 88Zr/88Y generators: A proof of concept study for a 70 MeV H[formula omitted] cyclotron

The large-scale production of 88Y with proton-induced reactions has been investigated from the perspective of new generation 70 MeV H− cyclotrons. Tandem target configurations are presented for both the direct production of 88Y as well as for producing 88Zr/88Y generators. Based on the relevant excitation functions, physical yields have been derived for 88Y production with Y2O3/SrCO3 tandem targets and 88Zr production with Zr/Y2O3 tandem targets. Yields are presented for optimized targets (i.e. optimum yield) as well as for balanced thermal loads on the individual targets. Liquid 88Zr/88Y generators have been produced using both natural Zr and Nb target materials, the former for dedicated productions and the latter as a byproduct by processing spent irradiated Nb capsules which normally would constitute radioactive waste. These stock solutions, which contain both the target material and 88Zr precursor, are retained virtually unchanged after processing except for the removal of 88Y on AG MP-50 macroporous cation-exchange resin. Methods are presented for the preparation of Nb stock solutions in hydrofluoric acid and Zr stock solutions in sulphuric acid. It is shown that multi-Ci productions of 88Y are feasible at a 70 MeV cyclotron facility, suitable for the needs of fracking applications. In addition, 88Zr/88Y generators can provide 88Y with very high specific activity, suitable for labelling of biomolecules. LA-UR-20-24305.

Resin loaded palladium nanoparticle catalyst, characterization and application in –C–C– coupling reaction

Macroporous ion-exchange resins were used to immobilize palladium (Pd) metal in order to produce nanoparticle catalysts. The complexation of palladium acetate and the following reduction with NaBH4 resulting Pd nanoparticles are loaded on to DIANION™ PK228 macroporous cation exchange resins. Palladium loading was characterized by inductively coupled plasma-atomic emission spectroscopy, field emission scanning electron microscope/energy-dispersive X-ray spectrometry, BET (Brunauer–Emmett–Teller) and HR-TEM. Palladium nanoparticles are loaded on to DIANION™ PK228 macroporous cation exchange resin which shows and excellent catalytic activity for Suzuki–Miyaura cross coupling reaction. Furthermore, the catalyst can be recycled without significant loss of its catalytic activity up to ten times.

An efficient procedure for preparing high-purity pingyangmycin and boanmycin from Streptomyces verticillus var. pingyangensis fermentation broth via macroporous cation-exchange resin and subsequent reversed-phase preparative chromatography

Pingyangmycin (PYM) and boanmycin (BAM), two individual components of bleomycin (bleomycin A5 and bleomycin A6), are glycopeptide antitumor antibiotics. An efficient procedure for the preparation of PYM and BAM from Streptomyces verticillus var. pingyangensis fermentation broth using macroporous cation-exchange (MCE) resin followed by medium-pressure preparative liquid chromatography (MPLC) based on monodisperse poly(styrene-co-divinylbenzene) (p(st-dvb)) microspheres was investigated in this paper. Nine frequently used MCE resins were screened by static adsorption and desorption to enrich PYM and BAM fromthe fermentation broth, and D157 resin was found to be the most effective. After one run of column-based dynamic adsorption and desorption, the contents of PYM and BAM were increased by factors of 13.8 and 12.1 with recovery yields of 84.21% and 81.47%, respectively. The enriched samples were subjected to MPLC with columns prepacked with the PolyRP 10-300 microspheres. The operational parameters of the MPLC, including the stationary phase and mobile phase compositions, sample/stationary phase ratio, sample loading scale and flow rate, were screened and optimized. The results showed that the separation and purification for PYM and BAM by MPLC were dramatically improved with a mobile phase modifier of 0.15 mol/L ammonium chloride aqueoussolution, a flow rate of 10 mL/min and a sample/stationary phase ratio of 1.0:100 (m/v, g/mL), and PYM and BAM with purities of more than 98.65% and 99.12% were obtained, respectively. The total recoveries of PYM and BAM reached 75.38% and 70.31%. The separation and purification method is simple, efficient, energy-saving, environmentally friendly and suitable for the large-scale preparation of high-purity PYM and BAM from Streptomyces verticillus var. pingyangensis fermentation broth.

Nanosized Iron Oxide Uniformly Distributed on 3D Carbon Nanosheets: Efficient Adsorbent for Methylene Blue

Magnetic carbon materials as adsorbents for dye removing have attracted increasing attention because of their magnetic separation feature. However, the immobilization of large magnetic particles on a carbon matrix greatly decreases the available sites for adsorption, resulting in a low adsorption capacity. The synthesis of magnetic carbon materials as adsorbents for dye adsorption with high adsorption capacity remains challenging. Herein, porous carbon (PC) was firstly synthesized through the calcination of macroporous acrylic type cation exchange resin. The as-prepared PC was applied as a matrix to deposit nano-sized Fe3O4 nanoparticles (MPC) via a facile one-pot solvothermal strategy. The nano-sized Fe3O4 nanoparticles (5.19 nm in diameter) are uniformly distributed on the PC surface. The MPC possesses an exceptional performance for methylene blue removal (qe = 214.4 mg g−1) at room temperature, outperforming most previous magnetic carbon adsorbents. The large surface area of the MPC originated from the combined advantages of PC and nano-sized Fe3O4 must be ascribed to the high performance of MPC composite toward methylene blue adsorption.

Kinetic modeling of catalytic esterification of non-edible macauba pulp oil using macroporous cation exchange resin

Conversion of non-edible oils through heterogeneous catalysis and their kinetic aspects are essential in order to produce economically viable biodiesel. Especially for oils containing high Free Fatty Acids (FFA) content since those cannot be viably converted through homogenous catalysis. Herein, the heterogeneous catalytic esterification kinetics of macauba pulp acid oil was exploited. The reaction tests were conducted in a stirred batch reactor with ethanol, and a cation exchange resin (Purolite® CT275)as a catalyst. The reaction kinetics was modeled based on a pseudo-homogeneous (PH) model of second order, showing good agreement with the experimental data acquired under different reaction conditions. The reaction progress was monitored by validated HPLC and GC methods. The internal and external mass transfer resistances were evaluated, and show that the rate limiting step is the surface reaction. To assess the catalyst stability, scanning electron microscopy was performed on both fresh and spent (after 10 reaction cycles) catalysts; reuse of catalyst was conducted without further treatment. The catalyst recycling demonstrates good performance where 85% of its performance was retained, and the SEM images show that the materials were structurally stable. Because the Pseudo-Homogeneous model properly described the kinetic aspects of the esterification process it was possible to estimate thermodynamic parameters by using the Arrhenius plot. The activation energy of the forward reaction was determined as 44.0 kJ/mol, while for the reverse reaction was 11.7 kJ/mol. Therefore, the kinetic and thermodynamic descriptions along with the catalyst stability upon several cycles without any further treatment reflect the viability of these resins for industrial application in the energy sector. Furthermore, combining these features with the low cost of macauba pulp acid oil, we conclude that the process is suitable for scaling up studies.

Continuous biosynthesis of geranyl butyrate in a circulating fluidized bed reactor

The continuous synthesis of geranyl butyrate in organic solvent was studied. The Candida rugosa lipase(CRL) was firstly immobilized on weak-acidic macroporous cation exchange resin D151. The batch experiments indicated that the adequate acid/alcohol molar ratio was 1:1.5 and the reaction time was 3.5–4 h. Then the continuous synthesis was realized with immobilized Candida rugosa lipase in a circulating fluidized bed reactor(CFBR). A stable ester yield of 77% was achieved under optimal conditions: enzyme loading 8 g, expansion ratio 1.6, feed flow rate 0.07 ml/min and butyric acid concentration 75 mmol/l. The results provide the basis for the scale-up of the process.

Development of an efficient method for separation and purification of trans -2,3-dihydro-3-hydroxyanthranilic acid from Pseudomonas chlororaphis GP72 fermentation broth

Abstract Trans-2,3-dihydro-3-hydroxyanthranilic acid (DHHA) is an important intermediate to synthesize a wide variety of secondary metabolites with potential biological activities. Recently, we engineered a biosynthetic pathway in Pseudomonas chlororaphis GP72 and optimized the batch- fermentation conditions to synthesize DHHA. Herein, we developed a proficient method for the separation and purification of DHHA from the culture extract of recombinant Pseudomonas chlororaphis GP72 by applying macroporous cation-exchange resins. The performance and absorption characteristics of six resins namely D001, HZD-2, JK006, HD-8, HZ016, and 732 were evaluated. Notably, HD-8 resin displayed the pronounced adsorption and desorption capacities for DHHA as compared to others and its equilibrium adsorption data were well-fitted to the Langmuir isotherm. Moreover, HD-8 column chromatography-based dynamic adsorption and desorption tests were carried out to standardize the operational parameters for DHHA separation and purification. Under the optimized separating conditions, the average adsorption capacity and desorption ratio of DHHA was 40.3 ± 0.7 mg/g dry resin and 86.7 ± 2.8%, respectively. The purity and recovery of DHHA was recorded to be 95.3 ± 1.2% and 83.2 ± 2.3%, respectively. Taken together, the HD-8 resin appeared as a promising adsorbent for high-level separation and purification of DHHA from the complex media. In conclusion, this method displays a high potential for separating and purifying DHHA and other bioactive compounds in high yield from the fermentation broth.

Studies on free fatty acid esterification of used cooking oil: investigation on the performance of sulphonated cation exchange resins

ABSTRACTUsed cooking oil (UCO) is one of the potential substitutes for conventional biodiesel feedstock. In this study, different types of macroporous cation exchange resins, namely RCP160M, RCP145H, PK228LH, PK216LH, PK208LH, SK104H and SK1BH, were used as catalysts in the UCO esterification process. These resins were characterised using Fourier transform infrared spectroscopy (FT-IR), nitrogen physisorption, scanning electron microscopy (SEM), an elemental analyser (CHNS), titration and a particle size distribution (PSD) analyser to determine their physicochemical properties. These catalysts were screened and RCP160M resin was found to give the best catalytic performance. RCP160M was used in subsequent studies focusing on the effect of different esterification variables. A conversion rate of 95% of free fatty acid (FFA) was achieved at the optimum condition with catalyst loading of 4 wt. %, reaction temperature of 60°C, and methanol-to-oil mass ratio of 18:1. RCP160M shows great potential as a catalyst in the biodiesel pre-treatment process as it outperformed the other catalysts and yielded maximum FFA conversion. This may be attributed to its higher specific surface area and total pore volume. The kinetic results revealed that the experimental data was best fitted to the Eley-Rideal model (Case II) with the activation energy of 37.2 kJ mol−1.

Adsorption equilibrium and kinetics of monomer–dimer monoclonal antibody mixtures on a cation exchange resin

Adsorption equilibrium and kinetics are determined for a monoclonal antibody (mAb) monomer and dimer species, individually and in mixtures, on a macroporous cation exchange resin both under the dilute limit of salt gradient elution chromatography and at high protein loads and low salt based on batch adsorption equilibrium and confocal laser scanning microscopy (CLSM) experiments. In the dilute limit and weak binding conditions, the dimer/monomer selectivity in 10mM phosphate at pH 7 varies between 8.7 and 2.3 decreasing with salt concentration in the range of 170–230mM NaCl. At high protein loads and strong binding conditions (0–60mM NaCl), the selectivity in the same buffer is near unity with no NaCl added, but increases gradually with salt concentration reaching high values between 2 and 15 with 60mM added NaCl. For these conditions, the two-component adsorption kinetics is controlled by pore diffusion and is predicted approximately by a dual shrinking core model using parameters based on single component equilibrium and kinetics measurements.

Free fatty acids esterification for biodiesel production using self-synthesized macroporous cation exchange resin as solid acid catalyst

Using high free fatty acids (FFAs) contents oil as the raw material for biodiesel production can reduce the production cost and make fully use of the bio-oil resources. Macroporous cation exchange resins contain numerous acid sites to catalyze heterogeneous esterification reactions to reduce the FFAs contents and prevent the saponification reaction. This study focuses on the synthesis and performance tests of the macroporous resin catalysts and its water deactivation mechanism. Self-synthesized macroporous cation exchange resins have a surface area of 185 m(2) g(-1) with an average pore diameter of 9.7 nm and the ion exchange capacity is 3.37 +/- 0.11 mmol g(-1). Owing to their pore structure, macroporous resin performs better than gel-type resin in low methanol concentration or high FFAs contents, but they show physical instability in reusability tests. The FFAs conversion reaches 97.8% (substrate oil with acid value of 64.9 mg KOH/g) under 100 degrees C and a methanol/FFAs molar ratio of 15:1 with 10 wt% catalyst loading. Water that originally exists in oil or that is produced in the reaction deactivates differently on the activity of the resin, but this deactivation can be decreased by increasing the reaction temperature. In this study, a linear relationship between original water content and esterified FFAs was identified and differences in deactivation models were investigated. (C) 2015 Elsevier Ltd. All rights reserved.

The production of 82Sr using larger format RbCl targets

The production of 82Sr at iThemba LABS is performed by the proton bombardment of a RbCl target using the facility's Vertical-Beam Target Station (VBTS). 82Sr is separated from the target material using a method based on target dissolution, using dilute ammonium chloride solution, and the use of chromatographic methods on Purolite S950 ion exchange resin. After performing a further purification step using AG MP-50 macroporous cation exchange resin, the result is a product with a high radionuclidic purity and negligible Rb and Fe impurity content.

Optimization of alkylphenols used as semiproducts in the production of additives on Amberlyst 36Dry macroporous sulfonic acid cation-exchange resin

The synthesis of alkylphenols used as semiproducts in the production of lube oil additives via the alkylation of phenol by ethylene oligomers in the presence of Amberlyst 36Dry macroporous catalyst is studied. The proposed Amberlyst 36Dry sulfonic acid cation-exchange resin allows us to simplify appreciably its pretreatment before use, and to increase the time of its operation, along with the rate, conversion, and selectivity of the process relative to the traditional KU2-8ChS catalyst. Ethylene oligomers containing the maximum amount of vinylidene and internal olefins are established to be most active in alkylation. Linear α-olefins are much less active in alkylation. The ratio of ortho- and para-alkylphenols is generally determined by the temperature and structure of olefins and remains nearly constant with an increase in the process time. The rate of converting alkylphenyl esters into alkylphenols is found to depend on the structure of the ester alkyl radical. Alkylphenols, which fully correspond to the imposed technical requirements as semiproducts used in the production of additives, can be synthesized with a nearly quantitative yield with respect to ethylene oligomers at 135.0°C and a molar ratio ethylene oligomers : phenol = 1.0 : 6.0.

Adsorption and Enrichment of Alkalids from Areca Nut by Means of Macroporous Resins

Resin adsorption as a means of separating and enriching areca alkalids from areca nut extracts was investigated. The adsorption/desorption properties of areca alkalids on six macroporous adsorption resins and a macroporous cation-exchange resin D151 were evaluated. The results showed that D151, AB-8 and XAD-7 resins presented a higher adsorption capacity, adsorption ratio and desorption ratio than the other resins studied. Equilibrium and kinetic adsorption data for areca alkalids onto these three resins were obtained. Such data were best fitted by the Langmuir isotherm model and the pseudo-first-order kinetic model. The thermodynamic and kinetic parameters showed that D151 resin possessed the greatest adsorption capacity and the highest adsorption rate of the three resins, with the adsorption of areca alkalids being spontaneous and endothermic.To optimize the operating parameters for enriching areca alkalids, dynamic adsorption and desorption tests were undertaken employing a column packed with D151 resi...

Synthesis of methylal by catalytic distillation

Methylal is an important raw material and an excellent solvent in industry. The conventional methods for the synthesis of methylal have drawbacks such as corrosion to the equipments, catalyst isolation, high molar ratio of methanol to formaldehyde and high cost of equipments. To overcome these drawbacks, the synthesis of methylal was investigated in a pilot scale catalytic distillation column using Sulzer BX and the structured catalytic packing Katapak-SP 12 in the present study. The reaction was catalyzed by polystyrene based macroporous cation exchange resin (D72) which was filled in the catalystic layers of the structured packings. The effects of operating parameters such as reflux ratio, total feed rate, molar ratio of methanol to formaldehyde, catalyst weight, aqueous formaldehyde concentration were studied experimentally. The appropriate operating parameters obtained in the present study include: reflux ratio is 5; total feed rate is 3.10 kg/h; molar ratio of methanol to formaldehyde is 2.5, catalyst weight is 0.51 kg, aqueous formaldehyde concentration is 35.3%. Under the above operating conditions the average conversion of formaldehyde is 99.6% while the average methylal purity is 92.1%. In order to achieve higher purity of methylal at the top of the column, two different configurations: feeding aqueous formaldehyde and feeding water at mid-way of rectifying section, was tried in the experiments. The experimental results show that the former configuration surpasses the latter, under which the average conversion of formaldehyde is 99.8% and the average methylal purity is 99.1%.

Selective Removal of Cu(II) Ions by Using Cation-exchange Resin-Supported Polyethyleneimine (PEI) Nanoclusters

A novel hybrid adsorbent D001-PEI was fabricated for selective Cu(II) removal by immobilizing soluble polyethyleneimine (PEI) nanoclusters within a macroporous cation exchange resin D001. Negligible release of PEI nanoclusters unexpectedly observed during operation may result from the porous cross-linking nature of D-001 as well as the electrostatic attraction between PEI and D001. Increasing solution pH from 1 to 6 results in more favorable Cu(II) retention by D001-PEI, and Cu(II) adsorption onto D001-PEI follows the Langmuir model and the pseudosecond-order kinetic model well. Compared to the host cation exchanger D001, D001-PEI displays more preferable adsorption toward Cu(II) in the presence of competing Mg(2+), Ca(2+), Sr(2+) at greater levels in solution. Fixed-bed adsorption runs showed that Cu(II) sequestration on D001-PEI could result in its conspicuous decrease from 5 mg/L to below 0.01 mg/L. Also, the spent hybrid adsorbent can be readily regenerated by 6-8 BV HCl (0.2 mol/L)-NaCl (0.5 mol/L) binary solution for repeated use with negligible capacity loss. The results reported herein validate that D001-PEI is a promising adsorbent for enhanced removal of Cu(II) and other heavy metals from waste effluents.