Selective Adsorption of Palladium(II) Complexes onto the Chelating Ion Exchange Resin Dowex M 4195 – Kinetic Studies

The chelating ion exchange resin – Dowex M 4195 was used in palladium(II) complexes adsorption from the acidic solutions. This study discusses the sorption kinetics, and more specifically the interparticle diffusion behavior of palladium(II) onto Dowex M 4195. The adsorption studies were used to determine the amount of palladium(II) complexes uptake (resin loading), the distribution coefficients, and the recovery efficiency of Pd(II) complexes. The influence of the agitation speed, the beads size (mean radius of swollen particles), the palladium concentrations, as well as acid concentrations (ionic strength of solutions), the macrocomponent addition (sodium chloride), and the phases contact time was also discussed. Moreover, the effect of temperature was taken into account during the determination of the isotherms. The experimental data obtained at 100 µg/cm³ Pd(II) initial concentration were applied to the kinetic models, and the sorption parameters as well as the normal standard deviation were calculated. Moreover, the Langmuir, Freundlich, and Tempkin‐Pyzhev isotherm models were applied and the isotherms parameters were calculated.     

Surface modification and metallization of polyimide using gold colloids as a seed layer

Herein we report on metallization of Cu on to surface‐modified polyimide resin, the method of which relies on potassium hydroxide‐induced modification of the polyimide surface to introduce carboxylic acid groups and incorporation of gold colloids as a seed layer through reduction of chloroauric acid. The contact angle of modified polyimide surface with water changed from 70 to 35° due to the hydrolysis of polyimide. Secondary amine group on the surface was detected with attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectrophotometry, suggesting that tertiary amine group has turned into secondary group. In addition, on the basis of hydrophilic behavior, we succeeded in depositing gold colloids on the chemically modified surface. SEM image of copper electroless plated on polyimide surface indicated that copper particles were compact and about ～ 300 nm in diameter. It showed that gold colloids provide an excellent conductive layer to catalyze the electroless plating of Cu on polyimide surface. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of low viscosity,fast UV curing solder resist based on epoxy resin for ink‐jet printing

A novel photosensitive low viscosity epoxy resin was synthesized by polyethylene glycol (PEG)‐modified bisphenol‐A epoxy resin (E51). The resin was modified by ethylene glycol, diethylene glycol, and different molecule weights (200,300,400) PEGs to optimize the minimum viscosity. FTIR was used to determine molecule structure. Cationic photoinitiator (UVI‐6976) mixed with modified resin (10 wt %), was utilized to boost the resin curing under UV light. The curing degree was beyond 90% within 40 s and the whole process was monitored by photo‐DSC. The modified resin diluted with ethylene glycol diglycidyl ether, was screen printed onto polyimide and polyethylene terephthalate substrate, and the properties of solder mask were up to China printed circuit association standard. The solder resist also meet all requirements under ink‐jet printing technology as the viscosity is under 60 mPa·s and the curing duration is <1 min. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Improvement in the adhesion of polyimide/epoxy joints using various curing agents

An improvement in the adhesion strength of polyimide/epoxy joints was obtained by (1) introducing a functional group on the polyimide surface, (2) improving the mechanical properties of the epoxy adhesive, (3) increasing the curing temperature, and (4) using polyamic acid as an adhesion‐promoting layer. The functional group on polyimide was introduced via treatment with aqueous KOH. An adhesion‐promoting layer was formed by spin coating polyamic acid onto a modified polyimide surface. The maximum adhesion strength of the polyimide/epoxy joint was obtained using polyamic acid as both the adhesion‐promoting layer and as the curing agent. The surface energy of the modified polyimide was examined using contact angle measurements and Fourier transform infrared spectroscopy, and the peel strength was determined by the T‐peel method. The peeled surfaces were analyzed using scanning electron microscopy and X‐ray photoelectron spectroscopy.© 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 812–820, 2002     

Kinetics and Equilibrium Studies for the Removal of Cobalt,Manganese, and Silver in Ethanol using Dowex 50W-x8 Cation Exchange Resin

Organic solvents such as ethanol, find a wide range of applications in fuel, pharmaceutical industries, food industries, and paint formulations, among others. The removal of Ag(I), Co(II), and Mn(II) ions in ethanol by cation exchange resin, Dowex 50W-x8, was investigated. The adsorption characteristics of metal ions onto Dowex 50W-x8 resin were described by Langmuir isotherms. The maximum sorption exchange capacities at 298 K were obtained as 47.4 mg g^?1, 52.6 mg g^?1, and 58.5 mg g^?1 for Ag(I), Co(II), and Mn(II), respectively. The data was also fitted to Temkin and Dubinin-Radushkevich adsorption isotherm models to evaluate other adsorption properties. The ion exchange of silver, cobalt, and manganese on cation exchange resin followed pseudo-second-order kinetics, and the intraparticle diffusion was rate-determining step. The thermodynamic parameters indicated that the sorption of metal ions onto Dowex 50W-x8 resin was spontaneous (negative ΔG°) and endothermic in nature (positive ΔH°) implying that the adsorption capacity increased with increasing temperature. The resin can be regenerated by eluting metal ions with 3.0 mol L^?1 HNO₃ followed by washing it with 10 mL of Millipore water and 10 mL of 2.0 M NaOH, respectively. The proposed method was applied for metal ion removal in real ethanol samples.     

TiCl4改性离子交换树脂催化合成甲缩醛

大孔阳离子交换树脂的磺酸基团与TiCl4络合,形成新的不会被阳离子交换而失活的Lewis酸中心。本文采用液固溶剂法制备金属改性离子交换树脂催化剂,应用于合成甲缩醛反应体系。实验考察了TiCl4负载量、负载温度和负载时间等工艺条件对催化活性的影响,通过正交实验获得了催化剂的较佳制备条件。研究结果显示,经TiCl4负载改性后的阳离子交换树脂的ggwis酸中心大幅度降低,催化活性显著提高。在相同实验条件下,合成甲缩醛的反应收率比改性前最大提高了13．5％,催化剂重复使用6次,催化活性无明显降低。     

Electrochemically assisted metal uptake by cation exchange based chemically modified electrodes

Carbon paste electrodes containing powdered cation exchange resin (Amberlite IR120) have been fabricated and applied to the uptake of copper ion in aqueous solution. The copper uptake reaction was carried out at open circuit and at different cathodic potentials. Linear potential sweep voltammetry was used to quantify the accumulated ions. With the application of an optimum cathodic potential, the amount of copper absorbed increased four to nine-fold in comparison with similar uptake at open circuit conditions. The effect of different resin size employed in the chemically modified electrodes, on the sensitivity of the electrode response was also studied as a function of peak current.     

Preparation and characterization of UV‐grafted ion‐exchange textiles in continuous electrodeionization

Ion‐exchange textiles (IETs) suitable for use in continuous electrodeionization (CEDI) stacks were prepared using the ultraviolet (UV)‐induced grafting of acrylic acid and sodium styrene sulfonate for cation‐exchange textiles, or 2‐hydroxyethyl methacrylate and vinylbenzyl trimethyl ammonium chloride for anion‐exchange textiles, onto nonwoven polypropylene fabric using benzophenone as photoinitiator. Although the ion‐exchange capacity (2.2 meq g^?1) of the prepared strong acid cation‐exchange textile was lower than that of IRN77 strong acid cation‐exchange resin (4.2 meq g^?1), the overall rate constant of IET was very high due to its low crosslinking and high specific surface area. There was no significant difference between the two different media in terms of the Co(II) removal rate. Furthermore, the current efficiency for IETs was higher than that of IRN77 cation‐exchange resin during a CEDI operation, with efficiencies of 60% and 20%, respectively. The IET also showed the faster exchange kinetics. Therefore, IETs prepared in this study proved to have desirable ion‐conducting characteristics within the CEDI systems. Also this study revealed that the primary removal mechanism in CEDI is the transport of ions through a medium and not the ionic capacity of a medium. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of novel ion-exchange resin based on polyimide containing 8-hydroxyquinoline as a pendent groups

Novel ion-exchange resin (PBMDDMCMHQ polyimide) having 8-hydroxyuinoline as a pendent groups was prepared using phenylenebismaleimide-diamine polyimide (PBMDDM) and 5-chloromethyl-8-hydroxyquinoline hydrochloride (CMHQ). Phenylenebismaleimide-diamine polyimide (PBMDDM) was prepared by Michael addition reaction of 1,3-phenylenebismaleimide (PBM) and 4,4’-diaminodiphenyl methane (DDM). The resulting ion-exchange resin was characterized by spectral techniques. Polymeric metal chelates of ion-exchange resin were also prepared using transition metal ions Zn(II), Cu(II), Ni(II), Co(II) and Mn(II), and were duly characterized. Ion-exchange properties of ion-exchange resin (PBMDDMCMHQ) for Fe(III), Zn(II), Ni(II) and Cu(II) metal ions were also studied by batch-equilibration method. The produced ion-exchange resin (PBMDDMCMHQ) has thermal stability up to 220°C and can be used over a wide pH range. It has good metal up take capacity at varying pH range and can be recycled.     

Controlled preparation of Pd/AC catalysts for hydrogenation reactions

A commercial activated carbon was submitted to different liquid oxidizing treatments in order to create a high density of carboxylic groups on the carbonaceous surface. Characterization of the modified activated carbon shows that it is possible to generate a large range in acidic group concentration without significant change of the textural properties. This ability allows us to introduce, by ion exchange, palladium cations up to 7.3 wt.%. This way of preparation, coupled to soft formaldehyde reduction, leads to highly dispersed metallic palladium catalysts. The resulting catalysts were tested in hydrogenation of cinnamaldehyde and exhibited a high hydrogenation efficiency compared to activities reported in the literature.     

离子交换纤维微观形貌特点及结构修饰研究

利用比表面积测试仪、扫描电子显微镜等物理化学方法对颗粒与纤维状离子交换剂的链间交联与微观形貌进行了研究,通过刚性交联剂对聚丙烯-苯乙烯-二乙烯基苯(PP-ST-DVB)离子交换纤维骨架结构进行了修饰改造。结果表明:离子交换纤维由于不能通过交联剂与致孔剂参与下的单体聚合构建具有丰富微孔的高分子骨架,所以不存在丰富孔结构和高比表面积特征,其内部为连续凝胶相结构;外比表面积大、传质距离短、交联键分布均匀是其反应动力学和渗透压稳定性能优异的主要原因;刚性交联剂在PP-ST-DVB纤维上的附加交联反应使其比表面积从原来的0.5 m~2/g提高到200 m~2/g以上,附加交联反应所形成的分子尺度微孔孔径分布窄,具有超高交联树脂的结构特点。     

Effect of ion exchange resin on increased surface area crystallization process for purification of vancomycin

We investigated the effects of ion exchange resins on the efficiency of crystallization with an increased surface area for the purification of vancomycin. As surface area-increasing materials, diverse types of ion exchange resin were used to increase the surface area per working volume (S/V). When the S/V was increased, in cation exchange resin Amberlite 200, Amberlite IR 120 (Na), and Amberlite IRC 50 and in anion exchange resin Amberlite IRA 400 (Cl) and Amberlite IRA 910 (Cl), vancomycin crystals were successfully generated. The yield of vancomycin increased (>97%), and the time necessary for crystallization was reduced dramatically (reduced from 24 hr to 12 hr). On the other hand, the purity of the vancomycin was approximately 95% and was not affected by increasing S/V. Use of an ion exchange resin also resulted in the production of smaller vancomycin crystals than in the absence of ion exchange resin.     

Kinetic of copper ion exchange onto iminodiacetic resin

The internal porosity and swelling/shrinking of a chelating iminodiacetic type ion exchange resin have been experimentally studied during the uptake of copper onto it. The swelling of the particle could be analyzed with a modified model on th basis of the unreacted core model (UCM), including the influence of chemical equilibrium. The ion exchange kinetic results in batch experiments are used with the UCM to calculate the effect of pH on the internal diffusion coefficients. Results from shallow bed experiments with mixed internal and external diffusion controls have shown the applicability of the above model to analyze ion exchange with low external velocities.     

Surface modification of mesoporous silica by radiation induced graft polymerization of styrene and subsequent sulfonation for ion-exchange applications

In this study, the fabrication of silica-grafted-sulfonated styrene (S-g-SSt) resin by grafting of styrene onto silanized silica via gamma radiation-induced polymerization and subsequent sulfonation of the grafted styrene is described. The grafting was strongly affected by the reaction conditions; absorbed dose, monomer concentration, and the type of solvent used. The structural analysis of the silica and all the relevant products were carried out by FTIR, SEM, TGA, XRD, and BET. FTIR analysis confirmed the presence of styrene onto silica and subsequent sulfonation. The BET nitrogen adsorption–desorption isotherms indicated that grafting occurs on the surface as well as inside the pores. Finally, the ion exchange capacity (IEC) of the fabricated S-g-SSt was evaluated by ion exchange titrations (back titration method). The IEC was found to be in the range of 0.43–2.97 meq/g depending on the degree of grafting. The facile fabrication method and high IEC value (2.97 meq/g) could lead to potential application of the fabricated S-g-SSt resin in ion exchange resin in waste water treatment and metal recovery. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48835.     

MECHANISM OF POLYMER-BASED SEPARATIONS. I. COMPARISON OF PHOSPHINIC ACID WITH SULFONIC ACID ION EXCHANGE RESINS

The metal ion complexing ability of the phosphinic acid polymeric extractant has been compared with that for the sulfonic acid ion exchange resin. Based on the performance of the extractants with Fe(III), Hg(II), and Mn(II) under dilute solution/ high acid conditions, both with and without the presence of a large excess of sodium ions, it is concluded that the phosphinic resin operates through an entropy-driven coordination for hard trivalent ions such as Fe(III), an enthalpy -driven coordination for soft ions such as Hg(II) and only ion exchange for hard divalent ions such as Mn(II). The sulfonic resin operates non-selectively through the ion exchange mechanism.     

Adsorption of cadmium ions from aqueous solutions by activated carbon with oxygen-containing functional groups

The adsorption of aqueous cadmium ions (Cd(II)) have been investigated for modified activated carbon (AC-T) with oxygen-containing functional groups. The oxygen-containing groups of AC-T play an important role in Cd(II) ion adsorption onto AC-T. The modified activated carbon is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5. Adsorption isotherms and kinetic study suggest that the sorption of Cd(II) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption. And the adsorbent has a good reusability. According to the FT-IR and XPS analyses, electrostatic attraction and cation exchange between Cd(II) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(II) adsorption.     

Extraction rate of palladium using divinylbenzene microcapsules containing tri-n-octylamine as the extractant

The extraction of palladium(II) from an aqueous hydrochloric solution was carried out using divinylbenzene microcapsules containing tri-n-octylamine as the extractant. The preparation of these microcapsules was affected by the preparation conditions, such as the concentrations of the divinylbenzene, tri-n-octylamine and diluent. In the case of extremely low or high concentrations of divinylbenzene, and for the high concentration of tri-n-octylamine, the matrix-type microcapsules could not be prepared. The morphologies the prepared of microcapsules were spherical and the surface of the microcapsules was very smooth. The adsorption of palladium(II) onto the microcapsules was negligible compared to the extraction of palladium(II), and it found that the adsorption of palladium(II) onto the microcapsules did not occur. The extraction of palladium(II) into the microcapsules was affected by the characteristics of microcapsules such as, the surface area, pore diameter and volume, and the encapsulation efficiency of the tri-n-octylamine. The extraction of palladium(II) into the microcapsules seemed to have three steps. The first extraction step is caused by the tri-n-octylamine existing near the surface of the microcapsules. The second step is caused by the internal diffusion. The final step is the extraction equilibrium. Based on these results, the microcapsule that has a high encapsulation efficiency of tri-n-octylamine and small pore diameter seems to show the high extraction performance.     

Synthesis and Surface Modification of Mesoporous Silicate SBA‐15 for the Adsorption of Metal Ions

Abstract

In this study surface modified SBA‐15, coated with octadecyltrichlorosilane (C18), is considered as an alternative adsorbent for metal ions in water. The SBA‐C18 was loaded with Bis(2,4,4-trimethylpentyl) phosphinic acid (cyanex 272) as the metal ion extractant. The adsorption characteristics of phosphinic acid loaded SBA‐C18 were evaluated for Cu(II) and Zn(II) ions in aqueous solution. Adsorption tests indicated that a contact time of 1 hour was sufficient for adsorption equilibrium to occur. The pH_1/2 values of Zn(II) and Cu(II) onto SBA‐C18, were found to be similar to published data for levextrel ion exchange resins and around 1 pH unit lower than published solvent extraction data for cyanex 272 in xylene.     

Adsorption of Ni(II) on ion exchange resin: Kinetics, equilibrium and thermodynamic studies

This article describes the ion exchange of a heavy metal Ni(II) from aqueous solutions onto a Dowex HCR-S, cationic resin. Batch adsorption studies were conducted to evaluate the effect of various parameters such as pH, resin dose, stirring speed, temperature, contact time and initial Ni(II) concentration on the removal of Ni(II). Adsorption rate increased with the increase in initial nickel concentration, stirring speed and temperature. Equilibrium adsorption isotherms were measured for the single component system, and the experimental data were analyzed by using Langmuir, Freundlich, Elovich, Temkin, Khan, Sips, Toth, Koble-Corrigan and Radke-Prausnitz isotherm equations. The Sips equation appears to fit the equilibrium data. Different models were tested for their applicability. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho??s pseudo-second-order and Elovich models. It was found that Ho??s pseudo-second-order model could be used for the prediction of the system??s kinetics. Thermodynamic activation parameters such as ??G*, ??S* and ??H* of the adsorption of Ni(II) on Dowex HCR-S cationic resin were also calculated.     

Analytical applications of newly synthesized copolymer resin derived from p‐aminophenol,dithiooxamide, and formaldehyde

A copolymer resin (p‐APDF) has been synthesized using the monomers p‐aminophenol, dithiooxamide, formaldehyde in 1 : 1 : 2M proportions in the presence of 2M HCl as catalyst. The structure of p‐APDF copolymer has been elucidated on the basis of elemental analysis and various physicochemical techniques, i.e., UV‐visible, FTIR, and ¹H‐NMR spectroscopy. The number average molecular weight of copolymer resin was determined by nonaqueous conductometric titration in DMF. Viscosity measurement were carried out in DMF indicate normal behavior. The prepared resin proved to be a selective ion exchange resin for some metal ions. The chelating ion exchange properties of this resin was studied for Fe(III) and Cu(II), Ni(II), Co(II), Zn(II), Cd(II), Pb(II) ions. A batch equilibrium method was used to study selectivity of metal ion uptake over a wide pH range and in media of various ionic strength. The resin showed a higher selectivity for Fe(III), Ni(II), Cu(II) ions than for Co(II), Pb(II), Zn(II), and Cd(II) ions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012