Separation and recovery of gold(III) from base metal ions using melamine–formaldehyde–thiourea chelating resin

Melamine–formaldehyde–thiourea (MFT) chelating resin has been prepared. Au³⁺ ions uptake behavior and selectivity of the chelating resin were investigated by both batch and column methods. MFT resin showed higher affinity toward Au³⁺ compared with base metal ions, Cu²⁺ and Zn²⁺. The highest Au³⁺ uptake values were obtained at pH 2 and Au³⁺ adsorption capacity of the resin was calculated as 48 mg Au³⁺/g resin (0.246 mmol Au³⁺/g resin) by batch method. It was concluded that Au³⁺ ions could be selectively concentrated from the solution including Cu²⁺ and Zn²⁺ base metal ions by column method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Removal of heavy‐metal ions from aqueous solution with nanochelating resins based on poly(styrene‐alt‐maleic anhydride)

Chelating resins have been considered to be suitable materials for the recovery of heavy metals in water treatments. A chelating resin based on modified poly(styrene‐alt‐maleic anhydride) with 2‐aminopyridine was synthesized. This modified resin was further reacted with 1,2‐diaminoethan or 1,3‐diaminopropane in the presence of ultrasonic irradiation for the preparation of a tridimensional chelating resin on the nanoscale for the recovery of heavy metals from aqueous solutions. The adsorption behavior of Fe²⁺, Cu²⁺, Zn²⁺, and Pb²⁺ ions were investigated by the synthesis of chelating resins at various pH's. The prepared resins showed a good tendency for removing the selected metal ions from aqueous solution, even at acidic pH. Also, the prepared resins were examined for the removal of metal ions from industrial wastewater and were shown to be very efficient at adsorption in the cases of Cu²⁺, Fe²⁺, and Pb²⁺. However; the adsorption of Zn²⁺ was lower than those of the others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction analysis, and differential scanning calorimetry analysis. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Thiourea modified hyper‐crosslinked polystyrene resin for heavy metal ions removal from aqueous solutions

A hyper‐crosslinked resin chemically modified with thiourea (TM‐HPS) was synthesized, characterized, and evaluated for the removal of heavy metal ions (Pb²⁺, Cd²⁺, and Cu²⁺) from aqueous solutions. The structural characterization results showed that a few thiourea groups were grafted on the surface of the resin with a big BET surface area and a large number of narrow micropores. Various experimental conditions such as pH, contact time, temperature, and initial metal concentration of the three heavy metal ions onto TM‐HPS were investigated systematically. The results indicated that the prepared resin was effective for the removal of the heavy metal ions from aqueous solutions. The isotherm data could be better fitted by Langmuir model, yielding maximum adsorption capacities of 689.65, 432.90, and 290.69 mg/g for Pd²⁺, Cd²⁺, and Cu²⁺, respectively. And the adsorption kinetics of the three metal ions followed the pseudo‐second‐order equation. FTIR and XPS analysis of TM‐HPS before and after adsorption further revealed that the adsorption mechanism could be a synergistic effect between functional groups and metal ions and electrostatic attraction, which may provide a new insight into the design of highly effective adsorbents and their potential technological applications for the removal of heavy metal ions from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45568.     

Synthesis and application of ion‐imprinted resin based on modified melamine–thiourea for selective removal of Hg(II)

A novel Hg(II) ion‐imprinted resin based on thiourea‐modified melamine was manufactured for selective elimination of Hg²⁺ from aqueous solutions. The polymerizable thiourea–melamine ligand together with its Hg(II) complex were extensively investigated using elemental analysis, Fourier transform infrared (FTIR) and ¹H NMR spectroscopies. The Hg(II) complex was used in a condensation polymerization in the presence of formaldehyde crosslinker and then the Hg(II) ions were leached out from the crosslinked polymeric network to finally leave the ion‐imprinted Hg‐PMTF resin. Both ion‐imprinted Hg‐PMTF and non‐imprinted resins were examined utilizing scanning electron microscopy and FTIR spectroscopy. The potential of the prepared resin for selective separation of Hg(II) ions from aqueous solutions was then evaluated by performing a series of batch experiments. Hg‐PMTF displayed an obvious rapid removal of Hg(II) ions with a pseudo‐second‐order kinetic pattern. In addition, the Langmuir adsorption isotherm model exhibited the best fit with the experimental data with comparatively high maximum adsorption capacity (360.5 mg g^?1). © 2015 Society of Chemical Industry     

Synthesis and adsorption properties,toward some heavy metal ions,of a new polystyrene‐based terpyridine polymer

A novel polymeric ligand having 2,2′:6′,2″‐terpyridine as pendant group was prepared through a Williamson type etherification approach for the reaction between 4′‐hydroxy‐2,2′: 6′,2″‐terpyridine and the commercially available 4‐chloromethyl polystyrene. The chelating properties of the new polymer toward the divalent metal ions (Cu²⁺, Zn²⁺, Ni²⁺, and Pb²⁺) in aqueous solutions was studied by a batch equilibration technique as a function of contact time, pH, mass of resin, and concentration of metal ions. The amount of metal‐ion uptake of the polymer was determined by using atomic absorption spectrometry. Results of the study revealed that the resin exhibited higher capacities and a more pronounced adsorption toward Pb²⁺ and that the metal‐ion uptake follows the order: Pb²⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺. The adsorption and binding capacity of the resin toward the various metal ions investigated are discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Adsorption of Cu2+ and Ni2+ from Aqueous Solution by Arabinoxylan Hydrogel: Equilibrium,Kinetic, Competitive Adsorption

In this work, arabinoxylan-graft-acrylic acid (AX-g-AA) hydrogel was prepared and used as an adsorbent to remove and recover Cu²⁺ and Ni²⁺ from aqueous solutions. The influences of pH, ligand content on the adsorption capacity of the hydrogel, adsorption equilibrium, and kinetic were studied in detail. The competitive adsorption and recovery of heavy metal ions, regeneration and reusability of the hydrogel were present. Furthermore, the relationship between the physiochemical properties of the adsorbent and its adsorption performance was also studied. The results showed that a more expanded network favored the diffusion and adsorption of metal ions. Cu²⁺ and Ni²⁺ uptake by this hydrogel was pH and concentration dependent with the maximum loading of 330.1 mg/g for Cu²⁺ and 248.7 mg/g for Ni²⁺. The pseudo-second-order kinetics suggested that the ion exchange process was chemisorption-controlled. The Langmuir equation could well describe the isotherm data. Cu²⁺ and Ni²⁺ adsorbed on the hydrogel could be effectively recovered in a diluted HNO₃ solution (0.01 M) in 30 min. AX-g-AA hydrogel also exhibited highly efficient reusability, and thus could be used repeatedly.     

Separation of gibberellic acid (GA3) by macroporous adsorption resins

Adsorption rates of gibberellic acid (GA3) on S‐8 and X‐5 resins were measured with the results indicating that the adsorption attained equilibrium for adsorption times longer than 4 h. The adsorption isotherms of GA3 on AB‐8, X‐5, S‐8, D4020, D3520, D4006 and NKA‐9 were determined at 20 °C. S‐8 resin had the largest solid/liquid distribution coefficient of 10.5 and was selected as the adsorbent for separation of GA3 from the aqueous solution. The breakthrough curves of GA3 from the aqueous solution on S‐8 resin were determined at different flow rates. The dynamic adsorption capacity of GA3 was measured as 4.56 mgg⁻¹ wet resin at a flow rate of 0.5 cm³min⁻¹. GA3 adsorbed on S‐8 resin was eluted with several eluents with 80% (v%) acetone aqueous solution having the best desorption performance. When GA3 was adsorbed by S‐8 resin from the fermentation liquor, the dynamic adsorption capacity of GA3 was increased to 12.02 mgg⁻¹ wet resin in virtue of the salting‐out effect of the ammonium sulfate in the fermentation liquor. The yield of GA3 was above 90% after GA3 was adsorbed by S‐8 resin from the fermentation liquor at pH 2 and eluted by 80% (v%) acetone aqueous solution. The GA3 concentration was increased seven‐fold from the fermentation liquor after an adsorption and desorption cycle. © 2000 Society of Chemical Industry     

Highly porous,water-swellable,and reusable chelating polymeric gels for heavy metal ion removal from aqueous waste

Sequestration and removal of heavy metal ions from aqueous solutions pose multiple challenges. Ease of synthesis, high adsorption capacity and ease of regeneration are important considerations in the design of polymeric adsorbent materials developed for this purpose. To meet this objective, a new approach was used to design and synthesize a highly porous polystyrene-based resin (IDASR15) bearing iminodiacetate functional groups in every repeat unit by free radical polymerization with N, N'-methylenebisacrylamide as crosslinker followed by base hydrolysis. The physiochemical chemical properties of the resin were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, equilibrium swelling value (ESV) and thermogravimetric analysis. Metal uptake capacity of IDASR15 towards low concentrations of various toxic heavy metal ions such as Cu²⁺, Cd²⁺, Mn²⁺, Zn²⁺, Pb²⁺, Ni²⁺, Co²⁺, Co³⁺, Cr³⁺, Fe²⁺, Fe³⁺, and Al³⁺ were investigated from their aqueous solution by batch method and found to be 0.943–2.802 mmol/g. The maximum capacity was 2.802 mmol/g obtained for Cu²⁺ ion at pH 5. The potential for regeneration and reuse has been demonstrated with Cu²⁺ ion by batch and column methods. The reported results suggest that IDASR15 is a highly efficient and porous complexing agent for commonly found toxic metal ions in aqueous streams with a high ESV of 68.55 g of water/1.0 g of IDASR15. It could also be reused ~99.5% of adsorption efficiency which is very promising and holds significant potential for waste-water treatment applications.     

Preparation of a New Polystyrene Supported-Ethylenediaminediacetic Acid Resin and its Sorption Behavior toward Divalent Metal Ions

A new polystyrene-supported ethylenediaminediacetic acid resin has been synthesized through a reaction between the amination of the commercially available 4-chloromethyl polystyrene polymer with ethylenediamine and the subsequent carboxymethylation with monobromoacetic acid, using ethylenediamine as spacer. The chelation behavior of this resin toward the divalent metal ions Cu²⁺, Ni²⁺, Zn²⁺, and Pb²⁺ in aqueous solutions was investigated. Batch equilibration experiments were carried out as a function of contact time, pH, amount of metal-ion, and polymer mass. The amount of metal-ion uptake of the polymer was determined by using atomic absorption spectrometry (AAS). Results of the investigation revealed that the resin exhibited higher capacities and a more pronounced adsorption toward Cu²⁺ and that the metal-ion uptake follows the order: Cu²⁺ > Zn²⁺ > Ni²⁺ > Pb²⁺. The adsorption and binding capacity of the resin toward the various metal ions investigated are discussed.     

Study of polymer‐metal ions triple complex as materials for adsorption and separation

Diethylenetriamine and a copolymer of sodium acrylate and maleic anhydride were used for the adsorption and separation of Au³⁺, Ru³⁺, Bi³⁺, and Hg²⁺ ions by forming polymer‐metal ions triple complex. The acidity, temperature, capacity, and interference on the adsorption of these ions on the complex, as well as the conditions of desorption of these ions from the complex, were investigated by means of inductively coupled plasma optical emission spectrometry. The results were satisfactory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 819–821, 1999     

Preparation of thiourea functionalized polyvinyl alcohol‐coated magnetic nanoparticles and their application in Pb2+ ions adsorption

We have prepared a novel kind of magnetic nanoparticle with high adsorption capacity and good selectivity for Pb²⁺ ions by modifying the magnetic nanoparticles with polyvinyl alcohol (PVA) and thiourea. The resultant magnetic nanoparticles were used to adsorb Pb²⁺ ions from aqueous solution. The influence of the solution pH, the adsorption time, the adsorption temperature, coexisting ions, and the initial concentration of Pb²⁺ ions on the adsorption of Pb²⁺ ions were investigated. The results indicated that Pb²⁺ ions adsorption was an endothermic reaction, and adsorption equilibrium was achieved within 30 min. The optimal pH for the adsorption of Pb²⁺ ions was pH 5.5, and the maximum adsorption capacity of Pb²⁺ ions was found to be 220 mg/g. Moreover, the coexisting cations such as Ca²⁺, Co²⁺, and Ni²⁺ had little effect on adsorption of Pb²⁺ ions. The regeneration studies showed that thiourea functionalized PVA‐coated magnetic nanoparticles could be reused for the adsorption of Pb²⁺ ions from aqueous solutions over five cycles without remarkable change in the adsorption capacity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40777.     

Adsorption of bismuth(III) by bayberry tannin immobilized on collagen fiber

The adsorption behavior of collagen fiber‐immobilized bayberry tannin towards Bi(III) at acidic pH values was investigated. The adsorption capacity of the adsorbent towards Bi(III) was 0.348 mmol g^?1 at 303 K, and increased with the rise in temperature. The adsorption isotherms of Bi(III) were in the shape of so‐called type II isotherms and could be described by an empirical equation, ln q_e = k + (1/n)C_e, which implies that chemical adsorption is predominant at lower concentrations of Bi(III) and that physical adsorption is involved at higher concentrations. The adsorption kinetics of Bi(III) on the immobilized bayberry tannin could be well described by the pseudo‐second‐order rate model, and the adsorption capacities calculated by the model were almost the same as those determined by actual measurements. The adsorbent could be regenerated by using 0.02 mol dm^?3 ethylenediaminetetraacetic acid (EDTA) solution after adsorption of Bi(III). The adsorption selectivity of the immobilized bayberry tannin towards Bi(III) in a Cu(II)–Bi(III) binary solution in acidic medium was remarkable. Therefore, it is strongly suggested that the immobilized bayberry tannin could be applied to the removal of Bi(III) from crude Cu(II) samples under proper conditions. Copyright © 2006 Society of Chemical Industry     

Cu2+ removal from aqueous solution by modified chitosan hydrogels

BACKGROUND: The adsorption of Cu²⁺ from aqueous solution using crosslinked chitosan hydrogels impregnated with Congo Red (CR) by ion‐imprint technology was systematically investigated with particular reference to the effects of contact time, pH, and initial concentration on adsorption. RESULTS: The adsorption capacity of the crosslinked chitosan without impregnation was only 68.68 mg g^?1 for Cu²⁺. However, the adsorption capacity increased from 77.42 (without imprint ion) to 84.54 mg g^?1 (imprint ion content 0.5 mmol) after the chitosan was impregnated with a ratio of 1/12 of CR to chitosan. The as‐prepared adsorbents were found to be pH‐dependent and the process of adsorption agreed well with the Freundlich isotherm. The loaded adsorbents could be regenerated and reused without the appreciable loss of capacity. CONCLUSION: Chitosan hydrogels impregnated with CR showed higher Cu²⁺ adsorption capacities compared with those prepared conventionally without imprint ion, and thus developed a good approach to increase Cu²⁺ adsorption efficiency in the treatment of waste‐water. Copyright © 2012 Society of Chemical Industry     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Melamine‐formaldehyde‐thiourea (MFT) Chelating Resin

Abstract

Melamine‐formaldehyde‐thiourea (MFT) chelating resin were prepared using melamine (2,4,6‐triamino‐1,3,5‐triazine), formaldehyde, and thiourea and this resin has been used for separation and recovery of silver(I) ions from copper(II) and zinc(II) base metals and calcium(II) alkaline‐earth metal in aqueous solution. The MFT chelating resin was characterized by elemental analysis and FT‐IR spectra. The effect of pH, adsorption capacity, and equilibrium time by batch method and adsorption, elution, flow rate, column capacity, and recovery by column method were studied. The maximum uptake values of MFT resin were found as 60.05 mg Ag⁺/g by batch method and 11.08 mg Ag⁺/g, 0.052 mg Zn²⁺/g, 0.083 mg Cu²⁺/g and 0.020 mg Ca²⁺/g by column method. It was seen that MFT resin showed higher uptake behavior for silver(I) ions than base and earth metals due to chelation.     

Synthesis and adsorption properties of macroporous cross‐linked polystyrene that contains an immobilizing 2,5‐dimercapto‐1,3,4‐thiodiazole with tetraethylene glycol spacers

A novel chelating resin macroporous cross‐linked polystyrene immobilizing 2,5‐dimercapto‐1,3,4‐thiodiazole via a hydrophilic tetraethylene glycol spacer (PS‐TEG‐BMT) is synthesized and the structure is characterized by means of Fourier transform infrared spectroscopy (FTIR), energy dispersive X‐ray microanalysis (EDX), and elementary analysis. Its adsorption capacity for several metal ions such as Hg²⁺, Ag⁺, Ni²⁺, Pb²⁺, Cd²⁺, Fe³⁺, Bi³⁺, Zn²⁺, and Cu²⁺ are investigated. The initial experimental result shows that this resin has higher adsorption selectivity for Hg²⁺ and Ni²⁺ than for the other metal ions and the introduction of hydrophilic TEG spacer is beneficial to increase adsorption capacities. The result also shows that the Langmuir model is better than the Freundlich model to describe the isothermal process of PS‐TEG‐BME resin for Hg²⁺. Five adsorption‐desorption cycles demonstrate that this resin are suitable for reuse without considerable change in adsorption capacity. POLYM. ENG. SCI., 45:1515–1521, 2005. © 2005 Society of Plastics Engineers     

Equilibrium data of the exchange of Cu2+, Cd2+ and Zn2+ ions for H+ on the cationic exchanger Lewatit TP‐207

Equilibrium ion exchange isotherms in aqueous medium of H⁺/Cu²⁺, H⁺/Zn²⁺ and H⁺/Cd²⁺ on a weak acid resin Lewatit TP‐207, at different pH values and at 298 K have been determined in order to assess the possibility of using ion exchange to eliminate heavy metal ions from industrial aqueous liquid streams. The experimental equilibrium data have been satisfactorily correlated using a Langmuir‐type empirical equation. It was found that the operating resin capacity with respect to each metal ion increased with increase in solution pH, in accordance with a second‐degree polynomial equation. Taking into account the variation of operating capacity with pH, each system exhibited a unique separation factor, namely all the experimental points can be described by a unique isotherm in a dimensionless form. Resin Lewatit TP‐207 exhibited the following selectivity order: Cu²⁺ > Zn²⁺ > Cd²⁺ at 298 K. Copyright © 2004 Society of Chemical Industry     

Molecularly Imprinted Ion-Exchange Resin for Fe3+

Abstract

Ion exchange resins selective for the sequestration of Fe³⁺ from aqueous solutions containing citrate were prepared by the molecular imprinting technique. Sorption characteristics of imprinted resins prepared with high (85 mole%) and low (3 mole%) amounts of covalent cross‐linking were examined. Experiments to determine loading capacity and selectivity, relative to several metal ions of physiological significance, were performed. The Fe³⁺ capacity of the highly cross‐linked resin was larger but the selectivity was lower.     

Adsorption of Pb2+ on Chitosan Cross‐Linked with Triethylene‐Tetramine

A novel triethylene‐tetramine cross‐linked chitosan (CCTS) was synthesized via the cross‐linking of triethylene‐tetramine and epichlorohydrin activated chitosan. Its structure was characterized by elemental analysis, infrared spectroscopy and X‐ray diffraction analysis, and the surface topography was determined with ESEM. The results were in agreement with expectations. The capacity of CCTS to adsorb Pb²⁺ ions from aqueous solutions was examined, and equilibrium and kinetic investigations were undertaken. The adsorption isotherms were fitted well by the Langmuir equation (R > 0.999). The maximum adsorbed amount, at pH 5.5, with an initial concentration of 3 mmol/L (621 ppm), was 378.8 mg/g. The adsorption process could be best described by a second‐order equation (R = 1). This suggests that the rate‐limiting step may be the chemical adsorption (chemisorption) step and not the mass transport. The separation factor used was 0 < R_L < 1. Therefore, it can be concluded that CCTS is an effective adsorbent for the collection of Pb²⁺.     

A Green Method to Fabricate Polyethyleneimine-Alginate Multilayer Coatings Modified Polyurethane Foam for Cu2+ Adsorption from Aqueous Solution

In this study, flexible polyurethane foam (FPUF) was modified with bio-based coatings composed of polyethylenimine (PEI) and alginate (ALG), fabricated by layer-by-layer (LbL) self-assembly. LbL self-assembled coatings modified FPUFs were studied for their potentials for removing Cu²⁺ ions from aqueous solutions by using batch adsorption technique, as a function of assembled bilayers number, pH value, carrier amount and adsorption time. The maximum adsorption capacity of the modified FPUF was shown to be 54 mg/g for Cu²⁺. Results suggested that the LbL self-assembly could potentially be a promising cost-effective technique for fabricating advanced adsorbent materials for removing pollutants from wastewater.     

Preparation of amidoximated bacterial cellulose and its adsorption mechanism for Cu2+ and Pb2+

Amidoximated bacterial cellulose (Am‐BC) was prepared through successive polymer analogous reactions of bacterial cellulose with acrylonitrile in an alkaline medium followed by reaction with aqueous hydroxylamine. It was used as an adsorbent to remove Cu²⁺ and Pb²⁺ from aqueous solutions. The adsorption behaviors of Cu²⁺ and Pb²⁺ onto Am‐BC were observed to be pH‐dependent. The maximum adsorption capacity of 84 and 67 mg g^–1 was observed, respectively, for Cu²⁺ and Pb²⁺ at pH 5. Scanning electronic microscopy (SEM) indicated that the microporous network structure of Am‐BC was maintained even after the modifacation. The adsorption mechanisms for Cu²⁺ and Pb²⁺ onto Am‐BC were investigated by fourier transform infrared spectroscopy (FTIR), ζ potential measurement and X‐ray photoelectron spectroscopy (XPS). The results revealed that the mechanism for the adsorption of Cu²⁺ onto Am‐BC could be mainly described as between metal ions and nitrogen atom in the amidoxime groups or oxygen atom in the hydroxyl groups. However, in the adsorption process for Pb²⁺, precipitation played the important role along with electrostatic interactions, although chelation action also existed in the process accounted for the adsorption process. The regeneration of Am‐BC was studied by treatment with a strong complexing agent, ethylenediaminetetracetic acid (EDTA). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010