Steric hindrance effect on adsorption of metal–organic complexes onto aminophosphonate chelating resin

Recovery of nickel and cobalt from organic acid complexes generated by bioleaching of nickel laterite ores with heterotrophic organism and their metabolites were conducted by ion-exchange. This study investigated specifically the adsorption of nickel and cobalt complexed with citrate, malate and lactate on chelating aminophosphonate Purolite S950 and the possible steric hindrance imposed by the larger bulky metal species on the resin loading capacity. Equilibrium adsorption tests of various concentrations of metal complexes were measured and analysed by fitting the experimental adsorption data to two empirical isotherm models: Langmuir and Freundlich. The distribution of nickel and cobalt speciation estimated from the stability and formation quotient constants of these metal complexes were used in examining the roles of steric hindrance in the adsorption of metal complexes on S950. Analysis of the mechanism of adsorption of these complexes suggests the size and the nature of the metal species have a significant influence on the metal uptake. In general the metal loading capacity of the resin increased as the size of the metal complexes decreased. The type and the number of anions which coordinated with the metal as ligands dictated the size of the complexes. An interesting outcome of this study, however, is the generally higher uptake of the weakly acidic lactate complex in comparison to the smaller hydrous nickel ion; thus suggesting the important roles of both physical and chemical properties of the metal species in their adsorption on resins. In general the order of the uptake of metal species on S950 is: lactate > metal ion > malate > citrate.     

Cobalt and nickel uptake by silica-based extractants

The pK_as of ethyl/butyl phosphonate silica (EBP-Si) have been determined, and the removal of cobalt and nickel from solution was investigated as a function of various parameters and compared with those of Purolite S950. pH uptake experiments suggested a combination of ion exchange and acid dissociation of the surface occurring. Isotherm data, fitted using the Langmuir and Dubinin–Radushkevich (D-R) models, indicated that stronger complexes formed with S950 than with EBP-Si. Kinetic data, fitted using a pseudo-second-order model, suggested that the rate-determining process is the reaction of metal ions with the chelating functionality of the resin. Uptake by EBP-Si is two to three times faster than that on S950.     

Metal recovery from jarosite waste – A resin screening study

Work has been carried out screening hydrometallurgical resins for application in the valorization of industrially produced jarosite. Of the seven resins tested, anion exchange resins performed poorly for valuable metal recovery. Purolite S950+ and S957, along with a strong acid resin, show good extraction properties, but are selective for Fe³⁺ over the other (divalent) metals. Purolite S930+ (iminodiacetic acid-functionalized resin) demonstrates selectivity for Cu²⁺ over Fe³⁺, but poor selectivity for Ni²⁺, Zn²⁺, and Co²⁺. Dowex M4195 (bispicolylamine-functionalized resin) demonstrates promise for extracting metals of value away from a mixed metal pregnant liquor solution (PLS). A three-stage column-based recovery process is proposed for jarosite leachate treatment.     

Synthesis of chelating resins with iminodiacetic acid and its wastewater treatment application

The chelating resins have high potential applications for the selective removal and recovery of metal ions from industrial waste solutions. The hydrophilic acrylate monomer with the iminodiacetic acid chelating group was prepared from glycidyl methacrylate and iminodiacetic acid at 60°C. The microbeads, prepared from acrylate monomer with the iminodiacetic acid chelating group, were employed by inversion suspension polymerization. In the pH range of 2–6, a reasonably good equilibrium sorption capacity is maintained for Cr³⁺ (ca. 2.7 mmol/g) and Cu²⁺ (ca. 1.8 mmol/g) in the chelating resins. The adsorption of Cd²⁺ and Pb²⁺ on microbeads is clearly affected by the pH of the solution, such that these ions' adsorption capacity increased with the pH of the aqueous solution. The adsorption of Cd²⁺ (ca. 1.25–1.87 mmol/g) and Pb²⁺ (ca. 0.99–1.89 mmol/g) showed a maximum at approximately pH = 5 and 6, respectively. The adsorption isotherms of Cr³⁺ and Cu²⁺ adsorbed on microbeads were following the Langmuir isotherm, but the adsorption behavior of Cd²⁺ and Pb²⁺ were not. The concentration of alkaline earth–metal cations on the range of 0–200 ppm had no influence on metal ions adsorbed capacity of chelating resins. Additionally, NTA (nitrilotriacetic acid) had no significant influence on metal ion adsorption by chelating resins. Furthermore, phenol pollutant can be adsorbed effectively by metal ions chelated microbeads; therefore, the microbeads were useful not only in recovering metal ions but also in the treating phenol pollutants in wastewater. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1353–1362, 2002; DOI 10.1002/app.10243     

Novel chelating resins with aminothiophosphonate ligands

Metal chelating resins containing aminothiophosphonate ligands were synthesised from two types of starting polymers: vinylbenzyl chloride/divinylbenzene and more polar acrylonitrile/ethyl acrylate/divinylbenzene. Both polymers were first modified with amines (ethylenediamine and diethylenetriamine) and subsequently reacted with diethyl thiophosphonochloridate. The resin based on the more polar polymer, containing 2.61 mmol/g phosphorus and 5.52 mmol/g nitrogen, modified with ethylenediamine was selected as the most promising for Cd/Ni separation. Sorption studies have been performed with 10⁻⁴ M Cd(II) and Ni(II) solutions in 0.2 M acetate buffer in the pH range 3.7–5.6. It has been found that the aminothiophosphonate resin is highly specific for Cd (log K_d=4–5), whereas Ni sorption is negligible. This new resin is compared with a commercial metal chelating polymer resin, Purolite S950, containing aminomethylphosphonate ligands.     

Macroporous polymeric ion exchangers as adsorbents for the removal of cationic dye basic blue 9 from aqueous solutions

Two macroporous cation‐exchange resins, Purolite C145, a strongly acidic cation macroporous resin, and Purolite C107E, a weakly acidic cation‐exchange resin, were used to remove the dye Basic Blue 9 (BB9) from an aqueous medium. Batch adsorption experiments were carried out to analyze the effect of various parameters, such as the phase contact time, initial dye concentration, initial solution pH, resin dose, and temperature. The experimental equilibrium data were evaluated by the Langmuir, Freundlich, and Dubinin–Radushkevich (DR) adsorption models. The Freundlich model better described the adsorption processes of the BB9 dye onto both cation exchangers, and the monolayer adsorption capacities were established as 31.9846 mg/g (C145) and 27.77 mg/g (C107E) at 20°C. The values of the mean free adsorption energy (E) obtained from the DR model suggested a porous structure of the adsorbents and proposed ion exchange at the main mechanism of the adsorption process. The values of the thermodynamic parameters showed that the retention of the cationic dye was a spontaneous and endothermic process. Environmental scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize the sorbent and also to validate the adsorption mechanism as ion‐exchange ones. The desorption experiments by a batch method were performed with different solutions: 0.1 and 1 mol/L HCl, 2.5 mol/L H₂SO₄, CH₃OH, and a mixture between 1 mol/L HCl and CH₃OH. Desorption performed with sulfuric acid was shown to be most effective because more than 85% of the adsorbed dye was removed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39620.     

Synthesis and characterization of sulphanilic acid–dithiooxamide–formaldehyde terpolymer resin for adsorption of nickel ions from waste water

A new chelating terpolymer resin of sulphanilic acid–dithiooxamide–formaldehyde (SDTOF) was synthesized. Dithiooxamide–formaldehyde (DTOF) was prepared by the reaction of dithiooxamide and formaldehyde. These resins were characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and scanning electron microscopy. Chelating resins beads were applied for adsorption of nickel (II) ions by batch and column techniques. Sorption experiments were performed by varying pH, agitation time, sorbent dosage and initial concentration of nickel (II) ion solution. SDTOF and DTOF resins showed adsorption capacity of 188.3 and 99.8 mg g^?1, respectively. Nickel adsorption isotherms data were fitted to Langmuir isotherm. Kinetic studies showed the adsorption process followed pseudosecond‐order rate model. Desorption of Ni(II) ions was done using 0.1 M HCl, HNO₃, and ethylenediamine tetraacetic acid solutions. The reusability of SDTOF and DTOF resins for the removal of Ni(II) ions was also determined after 10 sorption?desorption cycles. POLYM. ENG. SCI., 55:163–172, 2015. © 2014 Society of Plastics Engineers     

Sorption of Cd(II), Co(II), and Zn(II) Complexes with MGDA on Anion Exchange Resins: A Study of the Influence of Various Parameters

The strongly basic polystyrene gel resins Amberjet 4200, Amberjet 4600, and the macroporous strongly basic polystyrene Purolite A 520E were investigated for their sorption properties towards Cd(II), Co(II), and Zn(II) complexes with MGDA. The object of the study was the sorption behavior of three metal ions on the above-mentioned anion exchangers, depending on the metal ions’ concentration, pH, contact time, and temperature. MGDA is an alternative, environmentally friendly complexing agent. The sorption data were fitted to the Langmuir and Freundlich models. Three different kinetic behaviors: pseudo first order, pseudo second order, and intraparticle diffusion were tested. The variations of thermodynamic functions were also calculated.     

碱金属离子在树脂上的动态吸附行为

选取4种Na型树脂（D001、D113、Ls-1000、Ls-5000）为吸附剂,通过动态吸附法研究其对碱金属混合溶液的动态吸附行为,重点考察了其中铷、铯的分离性能,并考察了溶液pH、溶液组成、流速及树脂类型等对分离性能的影响。研究发现,中性条件下对铷、铯的吸附量顺序为离子交换树脂>螯合树脂。强酸性树脂D001对碱金属离子的亲和顺序为Cs+>Rb+>K+>Li+,其余3种树脂均为Cs+相似文献   

Removal of Cu2+ and Pb2+ ions from aqueous solutions by starch-graft-acrylic acid/montmorillonite superabsorbent nanocomposite hydrogels

In this study, the removal of copper(II) and lead(II) ions from aqueous solutions by Starch-graft-acrylic acid/montmorillonite (S-g-AA/MMT) nanocomposite hydrogels was investigated. For this purpose, various factors affecting the removal of heavy metal ions, such as treatment time with the solution, initial pH of the solution, initial metal ion concentration, and MMT content were investigated. The metal ion removal capacities of copolymers increased with increasing pH, and pH 4 was found to be the optimal pH value for maximum metal removal capacity. Adsorption data of the nanocomposite hydrogels were modeled by the pseudo-second-order kinetic equation in order to investigate heavy metal ions adsorption mechanism. The observed affinity order in competitive removal of heavy metals was found Cu²⁺ > Pb²⁺. The Freundlich equations were used to fit the equilibrium isotherms. The Freundlich adsorption law was applicable to be adsorption of metal ions onto nanocomposite hydrogel.     

Utilization of peanut shells as adsorbents for selected metals

Peanut shells of mesh size 10–20 were modified by combinations of treatments following a 3² factorial design. Treatments consisted of either no wash, water wash or base wash followed by no modification or modification with 0.6 M citric acid or 0.6 M phosphoric acid. The nine samples were evaluated for their uptake of five metal ions (Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II)) from solution. The results were compared with metal ion adsorption by three commercial cation exchange resins, namely, Amberlite® 200, Amberlite® IRC 718 and Duolite® GT‐73. The percent of metal ions adsorbed per gram of adsorbent was significantly increased by each of the acid treatments, average values ranged from 19 to 34% compared with non‐acid treated samples at 5.7%. The percent of metal ions adsorbed for base‐washed samples were higher than water‐washed or unwashed shells. Interaction between wash and acid treatment was not significant for most of the experimental conditions used. Acid‐treated samples were as effective as Duolite® GT‐73 in the adsorption of Cd(II) and almost twice as effective in the adsorption of Zn(II) from solutions containing a single metal ion. In solutions containing multiple metal ions, citric acid samples were found to be most effective and selective for Cu(II) compared with Cd(II), Ni(II), and Zn(II). In general, phosphoric acid‐modified shells removed the most metals from solution for the experimental samples and were more effective in removing Cd(II) and Zn(II) than two of the three commercial resins. Acid‐modified peanut shells are promising as metal ion adsorbents. © 1999 Society of Chemical Industry     

Kinetic and equilibrium modeling of liquid‐phase adsorption of lead and lead chelates on activated carbons

The sawdust (SD) waste generated in the timber industry was converted to a low‐cost activated carbon (SDAC) using a simpler and cheaper activation process, single‐step steam pyrolysis activation. The possibility of utilizing SDAC for the removal of lead (Pb(II)) in the absence of ligands and nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) chelated Pb(II) complexes from the liquid phase was examined and the results were compared with those for commercial activated carbon (CAC). SDAC shows a high adsorption capacity for Pb(II) and Pb(II) chelates compared with CAC. The extent of adsorption of Pb(II) and Pb(II) chelates on activated carbons was found to be a function of solution pH and species distribution of Pb(II) and Pb(II) chelates. The optimum pH range for the removal of Pb(II) in the absence of ligands by SDAC was 6.5–8.0, whereas its maximum removal by CAC was observed at pH 6.5. In the presence of ligands, the extent of Pb(II) adsorption was enhanced in the pH range 2.0–5.0 and was reduced significantly in the pH range 6.0–8.0. The maximum uptake of Pb(II) chelates for both carbons was observed at pH 5.0. Kinetic models such as pseudo‐first‐order, pseudo‐second‐order and pore diffusion were tested to investigate the adsorption mechanism. Batch kinetic studies showed that the adsorption of Pb(II) from aqueous solutions with and without ligands could be best described by a psuedo‐first‐order model for both carbons. The effect of pH on the adsorption isotherms of Pb(II) and Pb(II) chelates was also investigated. The applicability of the Langmuir and Freundlich isotherms, established for various initial concentrations of the adsorbate and for different pH values, was tested at 30 °C. Copyright © 2003 Society of Chemical Industry     

Chelating resins. V: Synthesis and characterization of chelating resins of formaldehyde-condensed phenolic Schiff bases derived from 4,4′-diaminodiphenyl sulphone with hydroxy benzaldehydes

The synthesis and characterization of a number of chelating resins having multiple functional groups capable of coordination to several metal ions is reported. The resins were synthesized by condensing Schiff bases derived from 4,4′-diaminodiphenyl sulphone and hydroxy benzaldehydes with formaldehyde and furfuraldehyde. The resins formed a number of polychelates with metal ions like Cu(II) and Ni(II). The Schiff bases, resins and the polychelates were charac-terized by IR, UV–vis., ¹H nuclear magnetic resonance spectra and thermogravimetric analysis. From the spectral data the possible coordination sites of the resins towards the metal ions were determined. The intrinsic viscosity of the resins was determined by viscometry in dimethylsulphoxide. The adsorption characteristics of the resins towards metal ions in dilute aqueous solutions were measured. The structure and the molecular geometry of the resins was observed to strongly influence the metal uptake behaviour, in addition to the influence of pH, temperature, particle size and metal ion concentration. Metallization of the resins significantly affected the thermal stability; the polychelates were found to be less stable than the resins. ©1997 SCI     

Studies of the adsorption of tetrasulfonated phthalocyanines on graphite substrate

The adsorption of iron and cobalt terasulfonated phthalocyanines (TsPcs) on ordinary pyrolytic graphite has been investigated as a function of pH and ionic strength of the adsorption solution as well as the potential. The charge corresponding to the voltammetric redox peaks of adsorbed complexes was used as a measure of the surface concentration. Adsorption of CoTsPc occurs readily from its freshly prepared aqueous solutions and is generally independent of pH. For FeTsPc, however, adsorption does strongly depend on pH. High surface coverage is achieved only from acid solutions rather than from pure water and alkaline solutions. This can be explained in terms of the form(s) of the complexes existing in the solution phase in the presence of air. uv-Visible spectroscopic studies coupled with the addition of CN⁻ to the macrocycle solutions provide evidence that in pure water and alkaline solutions FeTsPc exists predominantly in the μ-oxo form (FeTsPc)₂O, which seems not to favor the adsorption process. No evidence of the μ-oxo complex was found for FeTsPc in acid solutions and CoTsPc in aqueous solutions over the pH range examined (1–13). The adsorption of FeTsPc was at maximum when the potential was held at −0.55 V vs sce in 0.1 M NaOH.     

Studies of selective adsorption resin. XXIV. Preparation and properties of macroreticular chelating resins containing both polyethylenepolyamine side chains and mercapto groups

The macroreticular chelating resins containing both polyethylenepolyamine side chains and mercapto groups were prepared by the reaction of 2,3-epithiopropyl methacrylate-divinylbenzene macroreticular copolymer beads with polyethylene-polyamine. The adsorption behavior of metal ions on the obtained resins was then investigated. The amination of the macroreticular copolymer beads could effectively be carried out by treatment of the polymer beads with polyethylenepolyamine in organic solvent (benzene, terahydrofuran) or in the absence of organic solvent at 80°C or 100°C for 60 min. It was found that the adsorption capacity of the resins for metal ions is not only affected by the ion exchange capacity of the resins but also by the porosity of the resins. Hg²⁺, Ag⁺, and Cu²⁺ were effectively adsorbed on the resins even at a pH below 3, whereas Co²⁺, Ni²⁺, and Cd²⁺ were adsorbed at a pH above 3, Mn²⁺ at a pH above 7, and Ca²⁺ at a pH above 8. These metal ions adsorbed on the resins could easily be eluted with dilute mineral acid solution or dilute mineral acid solution containing thiourea.     

Formation of thermosensitive water‐soluble copolymers with phosphinic acid groups and the thermosensitivity of the copolymers and copolymer/metal complexes

Thermosensitive and water‐soluble copolymers were prepared through the copolymerization of acryloyloxypropyl phosphinic acid (APPA) and N‐isopropyl acrylamide (NIPAAm). The thermosensitivity of the copolymers and copolymer/metal complexes was studied. The APPA–NIPAAm copolymers with less than 11 mol % APPA moiety had a lower critical solution temperature (LCST) of approximately 45°C, but the APPA–NIPAAm copolymers with greater than 21 mol % APPA moiety had no LCST from 25 to 55°C. The APPA–NIPAAm copolymers had a higher adsorption capacity for Sm³⁺, Nd³⁺, and La³⁺ than for Cu²⁺, Ni²⁺ and Co²⁺. The APPA–NIPAAm (10:90) copolymer/metal (Sm³⁺, Nd³⁺, or La³⁺) complexes became water‐insoluble above 45°C at pH 6–7, but the APPA–NIPAAm (10:90) copolymer/metal (Cu²⁺,Ni²⁺, or Co²⁺) complexes were water‐soluble from 25 to 55°C at pH 6–7. The temperature at which both the APPA–NIPAAm copolymers and the copolymer/metal complexes became water‐insoluble increased as the pH values of the solutions increased. The APPA–NIPAAm copolymers were able to separate metal ions from their mixed solutions when the temperature of the solutions was changed; this was followed by centrifugation of the copolymer/metal complexes after the copolymers were added to the metal solutions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 116–125, 2004     

Adsorption of Uranium(VI) and Zirconium(IV) from Acid Solutions on Silica Gel

Abstract

Adsorption of uranium(VI) and zirconium(IV) from aqueous solutions on silica gel was investigated by the batch equilibration method. The influence of shaking time and concentrations of nitric acid (i.e., pH of solution) and metal ions in solution were studied. Adsorption of uranium(VI) and zirconium(IV) increases with an increase of pH (decrease of nitric acid concentration) and ion concentrations. The adsorption mechanism of uranium(VI) and zirconium(IV) from aqueous solutions on silica gel is proposed. It is shown that zirconium(IV) and uranium(VI) can be separated if the concentration of nitric acid in solution is higher than 0.01 mol/dm³.     

氨基丙二醇功能化硼螯合树脂的制备及其硼酸吸附性能

分别用3-氨基-1,2-丙二醇（3-APD）和2-氨基-1,3-丙二醇（2-APD）对多孔氯甲基聚苯乙烯树脂（CMPS）进行修饰,制备得到含邻、间位二羟基官能团的硼螯合树脂：PS-3-APD和PS-2-APD。用傅里叶红外光谱仪（FTIR）、元素分析仪（EA）、压汞仪（MIP）和激光粒度仪（LPS）对材料进行表征,确认功能单体成功接枝于氯球上。对两种树脂进行了静态提硼性能研究,分别考察了原料液pH、初始硼酸浓度、外来金属离子对硼酸吸附量的影响,当溶液pH为9.15～9.20时,两种树脂对硼酸吸附量最大;溶液中Na⁺、Mg²⁺、Ca²⁺的存在会一定程度削弱树脂对硼酸吸附性能。吸附动力学表明其吸附速率较快,且均满足准二级动力学模型。与Freundlich相比,吸附等温线更符合Langmuir模型,拟合得到的理论最大吸附量分别为0.730mmol/g和0.868mmol/g。本文对未来新型硼螯合树脂的开发及工业化应用提供参考和指导。     

γ‐radiation‐induced preparation of polyamidoxime resins and their adsorption of methyl violet

Poly(acrylic acid–amidoxime) [P(AA–AO)] and poly(maleic acid–amidoxime) [P(MA–AO)] resins were prepared by the γ‐radiation‐induced copolymerization of acrylonitrile with acrylic acid and maleic acid, respectively. The obtained resins were amidoximated by reaction with hydroxylamine. The prepared resins were used for the removal of methyl violet (MV) dye from aqueous solutions. Batch adsorption studies were made by the measurement of the effects of pH, the amount of adsorbent, the contact time, and the adsorbate concentration. The adsorption isotherm of MV onto P(AA–AO) and P(MA–AO) was determined at 25°C with initial MV dye concentrations of 10–70 mg/L. The equilibrium data were analyzed with the Langmuir and Freundlich isotherm models. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacities of 398.4 and 396.8 mg/L for P(AA–AO) and P(MA–AO), respectively. The kinetics of adsorption of MV onto P(AA–AO) and P(MA–AO) are discussed. The pseudo‐second‐order kinetic model described the adsorption of MV onto P(AA–AO) and P(MA–AO) very well. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Batch adsorptive removal of copper ions in aqueous solutions by ion exchange resins: 1200H and IRN97H

The removal of copper from aqueous solution by ion exchange resins, such as 1200H and IRN97H, is described. Effect of initial metal ion concentration, agitation time and pH on adsorption capacities of ion exchange resins was investigated in a batch mode. The adsorption process, which is pH dependent, shows maximum removal of copper in the pH range 2–7 for an initial copper concentration of 10 mg/L. The experimental data have been analyzed by using the Freundlich, Langmuir, Redlich-Peterson, Temkin and Dubinin-Radushkevich isotherm models. The batch sorption kinetics have been tested for a first-order, pseudo-first order and pseudo-second order kinetic reaction models. The rate constants of adsorption for all these kinetic models have been calculated. Results showed that the intraparticle diffusion and initial sorption into resins of Cu(II) in the ion exchange resins was the main rate limiting step. The uptake of copper by the ion exchange resins was reversible and thus has good potential for the removal/recovery of copper from aqueous solutions. We conclude that such ion exchange resins can be used for the efficient removal of copper from water and wastewater. This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University.