Polyacrylate anion exchangers in sorption of heavy metal ions with non-biodegradable complexing agents

The polyacrylate anion exchangers are widely used in purification of heavy metal ions from wastewaters and different accompanying complexing agents. Such effluents containing the chelators (EDTA, NTA, HEDTA, DTPA, and IDA) are discharged from relevant industries such as printed circuits boards, plating on plastics, metal finishing and others. The sorption was studied as a function of phase contact time and pH by the batch technique. It was found that the removal of heavy metal ions in the presence of EDTA, NTA and IDA strictly depends on the phase contact time and pH values. Various kinetic models such as the pseudo first-order and the pseudo second-order as well as the intraparticle one were also tested to estimate the sorption rate. The equilibrium capacities of the studied anion exchangers for Cu(II), Zn(II), Co(II), Ni(II), Pb(II) and Cd(II) in the presence of EDTA were the highest for Pb(II) and Cd(II). The order of sorption for Amberlite IRA 458, Amberlite IRA 958 as well as Amberlite IRA 67 can be as follows: Pb(II) > Cd(II) > Zn(II) > Cu(II) > Ni(II) > Co(II). The stability of forming complexes was also compared. The estimation of the capacities of anion exchangers under investigation by the continuous column studies was also carried out.     

Adsorption of Cr(III), Ni(II), Zn(II), Co(II) ions onto phenolated wood resin

In this study, phenolated wood resin was used an adsorbent for the removal of Cr(III), Ni(II), Zn(II), Co(II) ions by adsorption from aqueous solution. The adsorption of metal ions from solution was carried at different contact times, concentrations and pHs at room temperature (25°C). For individual metal ion, the amount of metal ions adsorbed per unit weight of phenolated wood resin at equilibrium time increased with increasing concentration and pH. Also, when the amounts of metal ions adsorbed are compared to each other, it was seen that this increase was order of Cr(III) > Ni(II) > Zn(II) > Co(II). This increase was order of Cr(III) > Ni(II) > Co(II) > Zn(II) for commercial phenol–formaldehyde resin. Kinetic studies showed that the adsorption process obeyed the intraparticle diffusion model. It was also determined that adsorption isotherm followed Langmuir and Freundlich models. Adsorption isotherm obtained for commercial phenol–formaldehyde resin was consistent with Freundlich model well. Adsorption capacities from Langmuir isotherm for commercial phenol–formaldehyde resin were higher than those of phenolated wood resin, in the case of individual metal ions. Original adsorption isotherm demonstrated the monolayer coverage of the surface of phenolated wood resin. Adsorption kinetic followed the intraparticle diffusion model. The positive values of ΔG° determined using the equilibrium constants showed that the adsorption was not of spontaneous nature. It was seen that values of distribution coefficient (K_D) decreasing with metal ion concentration in solution at equilibrium (C_e) indicated that the occupation of active surface sites of adsorbent increased with metal ions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2838–2846, 2006     

ADSORPTION AND SEPARATION BEHAVIOR OF COBALT,NICKEL, AND COPPER IN NITRITE MEDIUM BY ANION EXCHANGER

ABSTRACT

To investigate the possibility of separation of metal ions in nitrite medium by anion exchange, adsorption and elution behavior of the three typical transition metals of Co(II), Ni(II) and Cu(II) in nitrite solution with a commercial anion exchanger, Amberlite IRA-900 and a novel silica-based anion exchanger, AR-01 with fine particle size has been studied. Furthermore, the separation behavior of these metal ions in nitrite solution was demonstrated by anion exchange chromatography. Co(II) and Cu(II) showed strong adsorption onto the anion exchangers in nitrite solution, while the adsorption of Ni(II) was very weak. The adsorption is considered to result from the formation of anionic nitro-complexes. Complete separation of Co(II) from Ni(II), and Cu(II) from Ni(II) was achieved in column experiments with a dilute nitric acid as eluent. Compared to IRA-900, AR-01 showed significantly faster adsorption and elution kinetics.     

Studies on syntheses and properties of chelating resins based on chitosan

Chelating resins have some good adsorption properties for some metal ions, especially for several noble metal ions. Thus to retrieve rare metals using chelating resins is always an interesting project for chemistry researchers. In this study we synthesized a series of chelating resins based on chitosan and investigated adsorbing capacities, adsorption rates, and adsorption selectivities for Ag(I), Au(III), Pd(II), Pt(IV), Cu(II), Hg(II), and Zn(II). The results indicate that the resins have remarkable adsorbing capacities and adsorption rates for four noble metal ions and Hg(II). For instance, one of the resins adsorbs Au(III) and the adsorbing capacity is up to 7.11 mmol/g. However, the adsorbing capacities of the resins for Cu(II) and Zn(II) are much less than for the noble metal ions. Finally, x-ray photoelectron spectroscopy studies of a chelating resin and its metal chelates were made. The result reveals that the basis of the chelations is a chemical process. © 1996 John Wiley & Sons, Inc.     

Synthesis and metal ion adsorption studies of chelating resins derived from macroporous glycidyl methacrylate‐divinylbenzene copolymer beads anchored schiff bases

Two novel chelating resins are prepared by anchoring diethylenetriamine bis‐ and mono‐furaldehyde Schiff bases onto the macroporous GMA‐DVB copolymer beads and utilized for the adsorption towards Cu(II), Co(II), Ni(II), and Zn(II). FTIR spectra show that Schiff base groups have been successfully introduced into the polymer matrix and the chelating resins can form complexes with the metal ions. The chelating resins show a higher adsorption capacity toward Cu(II). The conductivity method can be used for determining the adsorption kinetics of the resins towards metal ions. The results show that the adsorption rates towards Cu(II) are much higher than those towards other ions and pseudo second‐order and intraparticle diffusion models can be applied to treat the adsorption amount‐time data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Calcined tetrabutylammonium kaolinite and montmorillonite and adsorption of Fe(II), Co(II) and Ni(II) from solution

Kaolinite and montmorillonite were modified with tetrabutylammonium (TBA) bromide, followed by calcination. The structural changes were monitored with XRD, FTIR, surface area and cation exchange capacity measurements. The modified clay minerals were used for adsorption of Fe(III), Co(II) and Ni(II) ions from aqueous solution under different conditions of pH, time and temperature. The uptake of the metal ions took place by a second order kinetics. The modified montmorillonite had a higher adsorption capacity than the corresponding kaolinite. The Langmuir monolayer capacities for the modified kaolinite and montmorillonite were Fe(III): 9.3 mg g^− 1 and 22.6 mg g^− 1; Co(II): 9.0 mg g^− 1 and 22.3 mg g^− 1; and Ni(II): 8.4 mg g^− 1 and 19.7 mg g^− 1. The modified kaolinite interacted with Co(II) in an endothermic manner, but all the other interactions were exothermic. The decrease of the Gibbs energy in all the cases indicated spontaneous adsorption.     

聚丙烯酸/丙烯酰胺高吸水性树脂吸附性能

用反相悬浮聚合法合成了聚丙烯酸/丙烯酰胺高吸水性树脂(PAAAM)，讨论了其吸附CuCl₂、NiCl₂、CoCl₂溶液中金属离子的性能，考察了溶液pH值和初始浓度对金属离子吸附的影响。结果表明，PAAAM在不同pH值及浓度区间，对金属离子的吸附能力有较大差异，可被用于Cu(II)、Ni(II)、Co(II)的分离。同时还探讨了PAAAM在混合金属离子溶液中的吸附性能及反复利用的可能性，发现在混合溶液中PAAAM表现出对Cu（II）有较好的选择性吸附能力；4次循环后对Cu(II)、Ni(II)、Co(II) 离子的吸附量为最大吸附量的80%以上，重复使用效果理想。     

Copolymeric network crown ether resins with pendent functional group: Synthesis and adsorption for metal ions

Three network crown ether resins with a high content of pendent functional groups were prepared and characterized by IR, elemental analysis, and thermal analysis. The slight variance of the thermal stability of the resins was related to the kind and content of the pendent functional group. The adsorption capacity of the resins for Mg(II), Cu(II), Co(II), Pb(II), and Hg(II) was determined. Toward Hg(II), the adsorption capacity of the resins was high and the adsorption process was easy and spontaneously performed. The XPS study showed that the adsorption of the NCR–SN resin toward Cu(II), Pb(II), and Hg(II) was mainly the coordinate interactions between the ligand atom (S, N) of the pendent functional groups and the metal ions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1457–1465, 2000     

Removal of heavy metals and neutralisation of acid mine drainage with un-activated attapulgite

Unactivated attapulgite was characterised and utilised as an adsorbent for the removal of heavy metal and neutralisation of acid mine drainage (AMD) from a gold mine. Adsorption experiments were carried out by agitation of a fixed amount of attapulgite with a fixed volume of AMD in a thermostatic shaker for varying times. Attapulgite showed that it can neutralise acid mine drainage as the pH after 4 h was 7.11. The results showed that metal ion removal after 4 h was 100% for Cu(II) and Fe(II), 93% for Co(II), 95% for Ni(II) and 66% for Mn(II) using a 10% (w/v) attapulgite loading. The experimental data best fit the Langmuir Isotherm with maximum adsorption capacities for Cu(II), Co(II), Mn(II), Fe(II) and Ni(II) being 0.0053, 0.0044, 0.0019, 0.01, and 0.0053 mg/g, respectively. The adsorption process fitted well the pseudo first order kinetics for Co(II) and Cu(II) and pseudo second order for Ni(II), Mn(II) and Fe(II). Thermodynamic data show that Cu(II), Co(II), Fe(II) and Ni(II) adsorption was thermodynamically spontaneous whilst Mn(II) was not thermodynamically spontaneous. The process is endothermic for Cu(II), Co(II), Mn(II), and Ni(II) and exothermic for Fe(II). Spent attapulgite (attapulgite that has already been used to remove metals) could be reused twice without regeneration.     

Preparation of amidoximated polyester fiber and competitive adsorption of some heavy metal ions from aqueous solution onto this fiber

In this study, a fibrous adsorbent containing amidoxime groups was prepared by graft copolymerization of acrylonitrile (AN) onto poly(ethylene terephthalate) (PET) fibers using benzoyl peroxide (Bz₂O₂) as initiator in aqueous solution, and subsequent chemical modification of cyano groups by reaction with hydroxylamine hydrochloride in methanol. The grafted and modified fibers were characterized by FTIR, TGA, SEM, and XRD analysis. The crystallinity increased, but thermal stability decreased with grafting and amidoximation. The removal of Cu(II), Ni(II), Co(II), Pb(II), and Cd(II) ions from aqueous solution onto chelating fibers were studied using batch adsorption method. These properties were investigated under competitive conditions. The effects of the pH, contact time, and initial ion concentration on the removal percentage of ions were studied. The results show that the adsorption rate of metal ions followed the given order Co(II) > Pb(II) > Cd(II) > Ni(II) > Cu(II). The percentage removal of ions increased with initial ion concentration, shaking time, and pH of the medium. Total metal ion removal capacity was 49.75 mg/g fiber on amidoximated fiber. It was observed that amidoximated fibers can be regenerated by acid without losing their activity, and it is more selective for Pb(II) ions in the mixed solution of Pb‐Cu‐Ni–Co‐Cd at pH 4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Thiourea- or Urea-Formaldehyde Chelating Resin

Abstract

In the present work, thiourea-formaldehyde (TF) and urea-formaldehyde (UF) chelating resins have been synthesized and they have been used in the adsorptions of Ag(I), Cu(II), and Zn(II) metal ions by batch and column methods. The effect of initial acidity of Ag(I) solution and the adsorption capacities of TF and UF resins by batch method and the separation of Ag(I) ions from Cu(II) and Zn(II) base metal ions by the column method were examined experimentally. The adsorption capacities of TF and UF resins were found as 58.14 and 47.39 mg Ag(I)/g by batch method and 30.7 and 4.66 mg Ag(I)/g, 0.80 and 0.121 mg Cu(II)/g, and under 0.002 mg Zn(II)/g by the column method, respectively. It was found that Ag(I) ions showed higher affinity towards TF resin than UF resin, compared with Cu(II) or Zn(II) ions, and Ag(I) could be separated more effectively by TF resin from Cu(II)and Zn(II) ions.     

Adsorption of some heavy metal ions from aqueous solutions on Nafion 117 membrane

Nafion 117 membrane was investigated for the removal of Ni(II), Co(II), Pb(II), Cu(II) and Ag(I) metal ions from their synthesized aqueous solutions. The different variables affecting the adsorption capacity of the membrane such as contact time, initial metal ion concentration in the feed solution, pH of the sorption medium and temperature of the solution were investigated on a batch sorption basis. The affinity of Nafion 117 membrane towards heavy metal ions was found to increase in the sequence of Cu(II), Ni(II), Co(II), Pb(II), and Ag(I) with adsorption equilibrium achieved after 30 min for all metal ions. Among all parameters, pH has the most significant effect on the adsorption capacity, particularly in the range of 3.1-5.9. The variation of temperature in the range of 25-65 °C was found to have no significant effect on the adsorption capacity. Nafion 117 membrane was found to have high stability combined with repeated regeneration ability and can be suggested for effective removal of heavy metal ions such as Cu(II), Ni(II) and Co(II) from aqueous solutions.     

Adsorption of Cu(II) ions from aqueous solutions using ion exchange resins with different functional groups

The extraction of heavy metals from industrial effluents using efficient adsorbents is crucial for wastewater treatment and beneficial for metal recycling. In this study, the removal of Cu(II) from an acidic solution by commercial resins Dowex G-26 and Puromet™ MTS9570 was investigated. The influences of contact time, solution concentration, pH, temperature, and a resin dosage on the adsorption process were studied with batch technique. The optimum adsorption conditions were obtained at a concentration of 1100 mg/L Cu, contact time of 30 min, pH 3.5, and resin dosage of 0.025 g/ml for the removal of 99.9% and 90% of copper ions by G-26 and MTS9570, respectively. The experimental data of copper adsorption were analyzed using the Langmuir, Freundlich, and Temkin isotherm models. The highest metal uptakes of 41.67 and 37.70 mg/g were observed for Dowex G-26 and MTS9570, respectively. It was found that both resins had higher adsorption capacities than the substances reported in the literature. The adsorption kinetic studies showed that the copper adsorption process could be better described by the pseudo-second order model. Adsorption occurs spontaneously under endothermic conditions, which indicates the endothermic nature of the process.     

Polyacrylate Ion Exchangers in Sorption of Noble and Base Metal Ions from Single and Tertiary Component Solutions

Two polyacrylic resins of different types such as Purolite S-984 (macroporous, chelating with a polyacrylic matrix supporting functional groups of the polyamine type) and Amberlite IRA-478RF (gel, intermediate polyacrylic anion exchanger with the tertiary amine and quaternary ammonium functional groups) were applied in removal of palladium(II) metal ions from HCl and HCl – HNO₃ solutions. Its sorption behaviors for base (Co(II), Ni(II), Cu(II), Ni(II)) and other noble metal (Pt(IV), Au(III)) ions, kinetics, and equilibrium studies were carried out in detail. The obtained results indicate that the resin is characterized by high sorption capacity and good kinetics of the sorption process. For the elution, the solutions of various reagents, that is, HCl, HNO₃, H₂SO₄, NaOH, NH₄OH, (NH₂)₂CS were studied as regards the complete release of the metal ions retained by the resin. Gold(III) could be eluted quantitatively from the loaded resin whereas Pd(II) and Pt(IV) could not by means of the applied eluting agent.     

Synthesis,characterization and application of a novel nanometer-sized chelating resin for removal of Cu(II), Co(II) and Ni(II) ions from aqueous solutions

A novel nanometer-sized chelating resin (NSCR) was prepared via two steps, First step: copolymerization reaction of N-methacryloxyphtalimide (NMP) with methylenebisacrylamide (MBA) by suspension polymerization method to give ultrafine poly (NMP-co-MBA). Second step: reaction of triethylenetetramine (TETA) with poly (NMP-co-MBA) to give NSCR. The prepared NSCR was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Brunauer-Emmett-Taller (BET) and thermogravimetric analysis (TGA). This study illustrated the capability of NSCR for extraction of Cu(II), Co(II) and Ni(II) from aquatic solutions. The pH effect, metal ions concentration, temperature and contact time were elaborated in batch experiments. The results showed that high capacities were 1.3, 1.0 and 0.95 mmol/g resin for Cu(II), Ni(II) and Co(II) ions, respectively. The experimental data of adsorption isotherms were convenient for Langmuir isotherm, and the kinetic data illustrated that the removal process was described by pseudo-second order kinetic model. The parameters of Thermo dynamic illustrated that the process of adsorption was endothermic and spontaneous reaction. The prepared NSCR was regenerated and used repetitively for five times with small decrease in adsorption capacity.     

Experimental study on functional graphene oxide containing many primary amino groups fast-adsorbing heavy metal ions and adsorption mechanism

Highly oxygenated graphene oxide was synthesized. Ethylenediamino graphene oxide (EDAGO) with many amino and hydroxyl groups was prepared for adsorbing heavy metal ions in wastewater. The maximum adsorption capacities of EDAGO for Pb(II), Cu(II), Ni(II), Zn(II) and Co(II) were 740.7, 97.0, 84.1, 70.8 and 68.2 mg/g, respectively, when pH values were 5.0, 4.0, 5.0, 5.0 and 5.0, respectively. Removal efficiencies of EDAGO for Pb(II), Cu(II) and Zn(II) were 99.2%, 95.8% and 93.9%, respectively; moreover, the adsorbent can be reused and exhibits very high removal efficiencies.     

Carbon nanotube filter for heavy metal ion adsorption

This study investigated carbon nanotube filtration technology using catalyst particles supported on silicalite-1–biomorphic carbon materials (BCMs). Aqueous solutions of Mn(II), Cu(II), Cr(III), Cd(II), and Pb(II) were used to test the efficiency of heavy metal ions removal. Carbon nanotubes (CNTs) were synthesized and grown on BCMs by the chemical vapor deposition method catalyzed with the catalyst (Co, Fe, and Ni). The synthesized CNTs with Co– and Fe– nanoparticles were typically multi-walled carbon nanotubes, and they showed good crystallinity (I_D/I_G = 1.05) and yield of (11.10 and 8.86) %. The removal efficiency of Mn(II), Cu(II), Cr(III), Cd(II), and Pb(II) ions using Co-catalyzed CNT filter was 97.57%, 98.01%, 97.89%, 97.42%, and 99.99%, respectively.     

Divinylbenzene-crosslinked polyacrylamide-supported dithiocarbamates as metal complexing agents

Summary Dithiocarbamate (DTC) functions were incorporated into divinylbenzene-crosslinked (2–20 mole %) polyacrylamides by a two-step polymer-analogous reaction. The complexations of these resins with DTC functions in different structural environments were investigated towards Co(II), Ni(II), Cu(II), Zn(II) and Hg(II) by batch equilibration technique. The metal ion intake decreased with the extent of the DVB content in the order Hg(II)>>Cu(II)>Zn(II)>Ni(II)>Co(II). The time-course on complexation, swelling behaviours of the uncomplexed and complexed resins, recyclability, IR and thermogravimetric characterisation of the complexes were carried out. The swelling of the resins decreased on complexation with metal ions and the thermal stability increased.     

Heavy metals uptake from aqueous solutions and industrial wastewaters by humic acid-immobilized polymer/bentonite composite: Kinetics and equilibrium modeling

This study explored the feasibility of utilizing a novel adsorbent, humic acid-immobilized-amine-modified polyacrylamide/bentonite composite (HA-Am-PAA-B) for the adsorption of Cu(II), Zn(II) and Co(II) ions from aqueous solutions. The FTIR and XRD analyses were done to characterize the adsorbent material. The effects of pH, contact time, initial adsorbate concentration, ionic strength and adsorbent dose on adsorption of metal ions were investigated using batch adsorption experiments. The optimum pH for Cu(II), Zn(II) and Co(II) adsorption was observed at 5.0, 9.0 and 8.0, respectively. The mechanism for the removal of metal ions by HA-Am-PAA-B was based on ion exchange and complexation reactions. Metal removal by HA-Am-PAA-B followed a pseudo-second-order kinetics and equilibrium was achieved within 120 min. The suitability of Langmuir, Freundlich and Dubinin-Radushkevich adsorption models to the equilibrium data was investigated. The adsorption was well described by the Langmuir isotherm model. The maximum monolayer adsorption capacity was 106.2, 96.1 and 52.9 mg g^?1 for Cu(II), Zn(II) and Co(II) ions, respectively, at 30 °C. The efficiency of HA-Am-PAA-B in removing metal ions from different industry wastewaters was tested. Adsorbed metal ions were desorbed effectively (97.7 for Cu(II), 98.5 for Zn(II) and 99.2% for Co(II)) by 0.1 M HCl. The reusability of the HA-Am-PAA-B for several cycles was also demonstrated.     

Solid Phase Extraction and Preconcentration of Trace Heavy Metal Ions in Natural Water with 2,2′‐Dithiobisaniline Modified Amberlite XAD‐2

Abstract

A solid phase extraction and preconcentration methodology utilizing a new chelating resin is described for the separation of Cd, Ni, Co, Cu, and Zn. The chelating resin matrix was prepared by covalently linking 2,2′‐dithiobisaniline synthesized from 2‐aminothiophenol with the benzene ring of polystyrene‐divinylbenzene resin Amberlite XAD‐2 through a –N?N– group. Its adsorption and preconcentration behavior for Cd, Ni, Co, Cu, and Zn in aqueous solution was studied using batch and column procedures in detail. The newly designed resin quantitatively adsorbs Cd, Ni, Co, Cu, and Zn above pH 5.0. Subsequent elution with 2 M HCl readily strips the sorbed metal ions from the resin. The sorption capacity is 360, 230, 170, 200, and 150 mol g^?1 for Cd, Ni, Co, Cu, and Zn, respectively. Their preconcentration factors are 80–200. The time for 80% sorption was less than 10 min for all five metal ions. The effects of electrolytes on the preconcentration were also investigated with the recoveries >95%. The procedure was validated by analysis of a standard reference river sediment material (GBW 08301 China). The developed method was successively utilized for the determination of Cd, Ni, Co, Cu, and Zn in tap water and river water by flame atomic absorption spectrometry (FAAS) after column SPE and preconcentration. The 3σ detection limits for these metal ions were found to be 0.10, 0.34, 0.42, 0.16, and 0.52 g L^?1, respectively. The relative standard deviation was <10% for the determination of 10 g each of Cd, Ni, Co, Cu, and Zn in a 100 mL water sample.