Metal Ion Retention Properties Research Articles

Stimuli‐sensitive nanostructured poly(sodium 4‐styrene sulfonate): Synthesis, characterization, and study of metal ion retention properties

ABSTRACTStimuli‐sensitive polymers are a type of smart polymers having the capability to change their configuration or properties under adequate stimuli as heat, pH, magnetic field, mechanical strength, among other. The aim of this work was to synthesize nanostructured polymers with antibacterial properties capable to change their retention properties of divalent metal ions by external stimuli (pH and ionic strength). For that, a polymerizable nanostructured crosslinker (PNC) based on silver nanoparticles (AgNPs) and acrylic acid was synthesized. Later, NPSS was synthesized by free‐radical polymerization, characterized by different analytical techniques and its retention properties of divalent ions (Cu2+, Fe2+, Mn2+, and Zn2+) were studied at different pHs and ionic strengths (5.0, 7.0, and 9.0; and 0.0, 0.5, and 1.5% NaCl, respectively). It was evidenced that AgNPs can be synthesized using acrylic acid as stabilizing agent, and later, be used for synthesis of NPSS by free‐radical polymerization. For NPSS, metal ion retention decreases as pH is increased; in addition, results suggest that the electrostatic interaction is not the only determining factor in the retention of ions. Other possible factors which would be affecting the retention are: water flow by swelling capacity and water flow by osmotic stress resulting of high salt concentration. NPSS showed antimicrobial activity against Escherichia coli and Staphylococcus aureus which was enhanced by incorporation of PNC based on AgNPs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46001.

Effect of the coupling agent on the properties of poly(acrylic acid)−Al2O3 interpenetrating hybrids and sorption of metal ions

AbstractIn this work we present the synthesis and characterization of a hybrid material based on poly(acrylic acid) (PAA), 3‐(trimethoxysilyl)propylmethacrylate (TMPM) and aluminium oxide (Al2O3). Hybrid materials applied for divalent cation retention were lead(II), cadmium(II), nickel(II) and copper(II) and the effect of the coupling agent TMPM was evaluated. The synthesis of the materials was carried out using a simultaneous radical polymerization/sol‐gel process for obtaining Al2O3−PAA composites using different amounts of TMPM as coupling agent. The physical and chemical properties of the hybrids were investigated using infrared spectroscopy, N2 absorption, SEM and TGA. The results indicate that all of the materials were simultaneous interpenetrating networks and that the morphologies and the properties depend on the amount of TMPM used. The metal ion retention properties were studied by a batch equilibrium procedure and sorption experiments were carried out under non‐competitive ion conditions. The hybrid exhibited metal ion uptake and dependence of metal sorption on the coupling agent content. Moreover, equilibrium sorption results are well described by Langmuir isotherms, and the sorption for different cations showed the following trend: Ni(II) < Cu(II) < Cd(II) < Pb(II). © 2014 Society of Chemical Industry

Metal ion sorption properties of water-insoluble resins based on sodium styrene sulfonate and different comonomers

A set of water-insoluble resins based on sodium styrene sulfonate and different comonomers were synthesized. The resins poly(mono-2-(methacryloyloxy)ethyl succinate-co-sodium 4-styrene sulfonate) P(MOES-co-SSNa), poly(2-acrylamido glycolic acid-co-sodium 4-styrene sulfonate) P(AGA-co-SSNa), poly(acrylamide-co-sodium 4-styrene sulfonate) P(AAm-co-SSNa), and poly(2-(dimethylamine)ethyl acrylate-co-sodium 4-styrene sulfonate) P(DMAEA-co-SSNa) were synthesized by solution radical polymerization. The metal ion retention properties were studied by batch procedure for Cd(II), Zn(II), Pb(II), and Hg(II). Resins performance was compared with a poly(sodium 4-styrene sulfonate) (PSSNa) resin in order to evaluate the effect of comonomer on sorption properties. The effect of pH, time, temperature, and maximum retention capacity were studied. In addition, sorption experiments were carried out under competitive ion conditions to study the selectivity of resins. The resins P(AAm-co-SSNa) and P(AGA-co-SSNa), showed the most important differences compared with PSSNa resin, the former present higher sorption and the latter presented selectivity for Hg(II) at pH 2.

Removal-concentration of pollutant metal-ions by water-soluble polymers in conjunction with double emulsion systems: A new hybrid method of membrane-based separation

The effect of reverse emulsion globules stabilized by non-ionic surfactants on metal-ion retention properties of poly(acrylic acid) was studied by continuous enrichment of external aqueous phase in a dead-end filtration system. Double emulsion systems were made by two-steps method confining an acid solution at pH 1.0 in the inside of reverse emulsion. Continuous phase of second dispersion stage was a poly(acrylic acid) solution at pH 6.0. By application of pressure, a divalent metal-ion stream, Cu 2+ and Cd 2+ at pH 6.0 was continuously added from a reservoir. Results indicate that it is possible to increase the maximum retention capacity of retention system above maximum retention capacity of poly(acrylic acid). The increase in the metal-ion retention can be explained via the macromolecular transport of metal-ions through oil phase of double emulsion. In general, a sequence given by linking of metal-ions by the polymer, adsorption of polymer on liquid–liquid interface, transporting of metal-ion and functional group regeneration is suggested and associated to the increases of overall system retention. Combination of water-soluble polymer and double emulsion systems appears as a novel alternative to remove and concentrate pollutant metal-ions in aqueous solution.

Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants

Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu2+ and Cd2+ at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer–metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced.

Metal Ion Removal Properties of Water‐Insoluble Functional Polymers

AbstractSummary: Resins containing sulfonic acid groups by radical polymerization were synthesized. The metal ion retention properties were studied by batch and column methods for the polluting metal ions Cd(II), Pb(II), and Hg(II).pH exercises an important effect on the retention: the metal ion sorption increases with increases in the pH. The maximum retention capacity was determined after three contacts at optimum pH. Resin R1 obtained the highest value 1.207 mmol/g resin for Cd(II). Different eluent reagents were used to recover the resin. Resin R1 loaded with Pb(II) was completely recovered using 4 M HCl as stripping reagent.

Use of Biopolymers for the Removal of Metal Ion Contaminants from Water

AbstractSummary: Naturally abundant biosorbants such as chitin and chitosan are recognized as excellent metal ligands, forming stable complexes with many metal ions, and serving as effective protein coagulating agents. Chitosan is a heteropolymer made of D‐glucosamine and a small fraction of N‐acetyl‐D‐glucosamine residues. Therefore, the adsorption ability of chitosan is found to be much higher than that of chitin, which has relatively fewer amino groups. Zeolites are crystalline microporous aluminosilicates with ion exchange properties suitable for a wide range of applications in catalysis and separation of liquid and gaseous mixtures. Incorporation in chitosan membranes is an effective method to control the diffusion outside the zeolite crystals and appropriately designed composite systems can find numerous opportunities for applications in wastewater treatment. In this paper we present the synthesis of zeolite‐chitosan and zeolite‐ethyl cellulose composites by encapsulation of clinoptilolite using a gelling solution of chitosan or an ethyl cellulose solution in ethyl acetate. The adsorption process of Cu2+ and Cd2+ on some adsorbents was investigated: clinoptillolite tuff (0.05 mm), chitosan flakes, ethyl cellulose, zeolite‐chitosan and zeolite‐ ethyl cellulose composites. Zeolite‐chitosan composites have been prepared by encapsulation of zeolites by a gelling solution of chitosan. Micrometric crystals of clinoptillolite were dispersed in a 3% chitosan solution in 1% aqueous acetic acid. The chitosan gel was formed and the zeolite crystals were encapsulated during the gelling process. The same procedure was used to obtain zeolite – ethyl cellulose composites. Study of the metal ion retention properties of different adsorbent materials was carried out using a steady state regime. The concentration of heavy metal ions in supernatant was determined by the atomic absorption spectrophotometric method. Adsorption isotherms of metal ions on adsorbents were determined and correlated with common isotherm equations such as Langmuir and Freundlich models.

Polymer-enhanced ultrafiltration: counterion distribution and its relation with the divalent metal-ion retention properties by sulfonic acid polyelectrolytes

The distribution of divalent counterions and its relation with the retention properties of sulfonic polyelectrolytes were analyzed, and the results were interpreted under the light of the counterion condensation theory using two-zone model and Donnan’s equilibria. In this regard, poly(vinyl sulfonic acid) and sodium poly(styrene sulfonate) solutions at pH 6.0 were diafiltered by the liquid-phase polymer-based retention technique. Metal-ion retention and distribution around polyelectrolyte chains were obtained from the diafiltration experiment as well as the maximum retention capacity (MRC) for each polymer. The MRC values obtained were 0.30, 0.15, 0.21, and 0.26 mmol of metal-ion per mmol of polymer for PVSA–Cu2+, PVSA–Cd2+, PSS–Cu2+ and PSS–Cd2+, respectively. The excess of ions added, the volume in the inside cell, and the order of addition of the ions contacted with the polymer were important factors defining the form of the retention profile.

Studies on Hg(II) ion retention properties of cross-linked graft copolymer of acrylic acid and its analytical application

The effects of different parameters such as time, concentration, pH and temperature, on metal ion retention properties of the polymer have been investigated. Metal ion adsorption kinetics, isotherms and thermodynamics have been studied. A plausible mechanism for mercury ion retention has been suggested. Mercuric ion has been isolated quantitatively from various synthetic mixture containing metal ions (Ni2+, Cd2+, Pb2+ and Zn2+).

Heavy metal ions removal through poly(acrylamide-co-methacrylic acid) resin

The resin poly(acrylamide-co-methacrylic acid) P(AAm-co-MA) by radical polymerization was synthesized and its metal ion binding was studied using the batch and column equilibrium procedures for: Cd(II), Zn(II), Pb(II), Hg(II), Al(III), and Cr(III). Experiments were carried out at different pH, metal ion concentration, temperature, and contact time. The resin’s retention behavior was influenced by the pH. The highest retention 91% (0.248 mmol/g, 6.7 mg/g) was achieved at pH 5 for Al(III), and 87% (0.265 mmol/g, 54.9 mg/g) for Pb(II). For Hg(II), the yield was 85% (0.318 mmol/g, 63.7 mg/g) at pH 2. The metal-ion retention properties were dependent on the polymer/metal ion ratio. Under competitive conditions of Pb(II), Hg(II), and Al(III), the resin showed a higher retention of Hg(II), allowing the selective separation of this metal.

Synthesis and metal ion adsorption properties of poly(4‐sodium styrene sulfonate‐co‐acrylic acid)

AbstractThe water‐insoluble resin poly(sodium 4‐styrene sulfonate‐co‐acrylic acid) was synthesized through a solution radical polymerization with ammonium persulfate as an initiator and N,N′‐methylene‐bis‐acrylamide as a crosslinking reagent (CR) at different amounts (2, 4, 6, and 8 mol %). The polymerization yield ranged from 75 to 91%. The metal ion retention properties were studied by batch and column equilibrium procedures for: Cd(II), Cr(III), Zn(II), Al(III), Pb(II), and Hg(II). These properties were investigated under competitive and noncompetitive conditions. The effect of pH, particle size, time, temperature, and initial metal ion concentration on metal ion adsorption was investigated. The resins showed a high retention ability for Hg(II) ions over 85% at pH 2 and for Cd(II), Cr(III), Zn(II), and Pb(II) over 96% at pH 5. The maximum adsorption performance for Pb(II) was achieved as 148.5 mg/g at an optimum pH. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Aminodiacetic water-soluble polymer–metal ion interactions

The retention properties for metal ions, the maximum retention capacity, the antibacterial and mutagenic activity of water-soluble metal ion complexes from water-soluble poly[2-hydroxy-(3-methacryloyloxypropyl)aminodiacetic acid] P(HMPADA) were studied. HMPADA was synthesized by radical polymerization in aqueous solution. The water-soluble polymer (WSP) P(HMPADA), containing ester, hydroxy, tertiary amine, and two carboxylic acid groups in every monomeric unit was investigated as polychelatogen in view of its potential metal ion binding properties using the liquid-phase polymer based retention (LPR) technique under different experimental conditions. The water-soluble complexes were investigated as biocides. Metal ions investigated at pH 3, 5, and 7 were: Ag +, Co 2+, Ni 2+, Cu 2+, Zn 2+, Cd 2+, Pb 2+, Al 3+, Cr 3+, and Fe 3+. Depending on pH, P(HMPADA) showed a different interaction affinity, where the highest interaction occurred at pH 7. Polymer–metal ion interaction showed the following affinity order: tri-valent >di-valent >mono-valent ion. Maximum retention capacity (MRC) ranged between 17.2 and 342.2 mg metal ion/g polymer for Cu 2+ and Ag +, respectively. FT-IR showed a variation in νC O, νΟ−C O, νOH absorption signals, and Far-IR showed new signals corresponding to metal–O and metal–N interaction, indicating a participation of carboxylic acid, amine, and hydroxy groups of polymer–metal ion complexes. Antibacterial activity of Ag +, Cu 2+, Zn 2+, and Cd 2+ complexes were studied. These complexes presented a higher biocide activity against Staphylococcus aureus (Gram-positive) than for Escherichia coli (Gram-negative) with a lowest minimum inhibitory concentration (MIC) of 4 mg/mL for polymer-Cd 2+ complex. Scanning electron microscopy (SEM) showed the interaction between polymer–metal ion complexes and bacteria surface. All samples showed low genotoxic activity.

Removal of environmentally impacting metal ions using functional resin poly(4‐styrene sulfonate‐co‐4‐vinylpyridine): Synthesis and metal ion retention properties

AbstractA water‐insoluble polymer, poly(sodium 4‐styrene sulfonate‐co‐4‐vinylpyridine), was synthesized by radical polymerization at different amounts (2, 4, 6, and 8 mol %) of crosslinking reagent (CR). The polymerization yield ranged from 83.5% to 100.0%. The resin is characterized by FT IR spectroscopy, thermal analysis, and scanning electron microscopy. The water absorption capacity, WAC (110 g/g dry resin), was obtained for the resin with a 2 mol % of CR. The metal ion affinity is studied by Batch equilibrium procedure under different experimental conditions for the cations: Hg(II), Cd(II), Zn(II), Pb(II), Cr(III), and Al(III). The metal ion affinity increased as the pH increased. At pH 5, the resin presented an affinity above 90% for all metal ions. Hg(II) presented the highest retention value at pH 2. The maximum metal ion retention capacity is determined at optimum pH for Hg(II), Cd(II), Pb(II), and Zn(II). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1769–1774, 2007

Poly(2-acrylamido glycolic acid): A water-soluble polymer with ability to interact with metal ions in homogenous phase

A water-soluble polymer, poly(2-acrylamido glycolic acid) was obtained by radical polymerization and characterized by FT-IR, 1H NMR, and 13C NMR spectroscopy. The metal ion retention properties were investigated through the liquid-phase polymer based retention (LPR) technique at different pHs and filtration factor Z. The affinity of the ligand groups for the metal ions depends strongly on the pH. At lower pH, the retention is lower than 50%, which increased as the pH increased. At pH 5, the polymer showed a high affinity and selectivity for Pb(II), and at pH 7 the P(AGA) formed stable complexes with Cu(II), Co(II), Ni(II), Cd(II), and Pb(II). Of the three potential ligand groups, amide, hydroxyl, and carboxylate groups, the carboxylate groups form the more stable complexes with the metal ions.

Metal ion retention properties of water‐insoluble polymers containing carboxylic acid groups

AbstractCrosslinked poly(acrylic acid), PAA, and poly(2‐acrylamidoglycolic acid), PAAG, were synthesized by radical polymerization. Both resins contain carboxylic acid groups. PAA at basic pH exists basically as an acrylate anion and PAAG shows three atoms or groups, carboxylic acid, hydroxyl, and amide groups, that can act as ion exchanger or chelating groups. Both resins are studied as adsorbents to trace metal ions from saline aqueous solutions and natural sea water and their properties by Batch equilibrium procedure are compared. The metal ions studied under competitive and noncompetitive conditions were Cu(II), Pb(II), Cd(II), and Ni(II). The effects of pH, time of contact, amount of resin, temperature, and salinity were studied. Resin PAA shows a high affinity (>80%) for Cu(II) and Cd(II) and resin PAAG shows also a high affinity for Ni(II), Pb(II), and Cd(II). By treatment of the metal ion‐loaded resin with 4M HNO3 it is possible to recover completely the Cu(II) ions from resin PAA and Ni(II) and Pb(II) from resin PAAG. The metal ion retention properties were studied with natural sea water. For those natural sea waters containing Cu(II) and Cd(II), the resins showed a high affinity for Cd(II) ions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 697–705, 2006

Resins containing amino and carboxylic acid groups. Synthesis, characterization, and metal ion retention properties

AbstractThe crosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide], P(MAPDSA), and poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐acrylic acid], P(MAPDSA‐co‐AA), were synthesized by radical polymerization. The resins were completely insoluble in water. Due to the lower metal ion retention of P(MAPDSA), the metal ions investigated under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) ions by batch and column equilibrium procedures were carried out only for P(MAPDA‐co‐AA), particularly for Hg(II). The resin–Hg(II) ion equilibrium was achieved before 15 min. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.89 meq/g. The resin showed a high selectivity to Hg(II) ions. The recovery of the resin was investigated at 25°C with different concentrations of HNO3 and HClO4. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 525–530, 2005

Metal ion retention properties of poly(acrylic acid) and poly[N‐3‐(dimethylamino)propyl acrylamide‐co‐acrylic acid

AbstractThe crosslinked resins poly(acrylic acid) (PAA) and poly[N‐3‐(dimethylamino)propyl acrylamide‐co‐acrylic acid] [P(NDAPA‐co‐AA)] are obtained by radical polymerization and characterized by FTIR spectroscopy. PAA at basic pH exists basically as an acrylate anion that may contain end carboxylate groups or form bridges acting as mono‐ or bidentate ligands. P(NDAPA‐co‐AA) presents three potential ligand groups in its structure: carboxylic acid, amide, and amine. The trace metal ion retention properties of these two resins is compared by using the batch equilibrium procedure. The metal ions are contained in saline aqueous solutions and are found in natural seawater. The retention of Cu(II), Pb(II), Cd(II), and Ni(II) metal ions is studied under competitive and noncompetitive conditions. The effects on the pH, contact time, amount of adsorbent, temperature, and salinity are investigated. The PAA resin presents a high affinity (>80%) for Cu(II) and Cd(II) ions. The P(NDAPA‐co‐AA) resin shows a high affinity for Pb(II) and Cd(II) ions. With 4M HNO3 it is possible to completely recover the PAA resin charged with Cu(II) ions and the P(NDAPA‐co‐AA) resin charged with Pb(II) ions. The two resins show a high affinity for Cd(II) ions from the seawater containing Cu(II) and Cd(II) ions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1385–1394, 2005

Trace metal ion retention properties of crosslinked poly(4‐vinylpyridine) and poly(acrylic acid)

AbstractThe crosslinked resins poly(4‐vinylpiridine) (PVPy) and poly(acrylic acid) (PAA) were obtained by radical polymerization. PVPy shows monodentate ligands and PAA at basic pH is basically as acrylate anion, which can contain end‐carboxylates groups or form a bridge acting as mono‐ or bidentate ligands. The retention properties for trace metal ions from saline aqueous solutions and natural seawaters of these two resins were investigated by Batch equilibrium procedure. The metal ions studied were Cu(II), Pb(II), Cd(II), and Ni(II). The following effects were studied: pH, contact time, amount of the adsorbent, temperature, and salinity. The resin PVPy showed a high affinity for Cd(II) and PAA for Cu(II) and Cd(II). The metal ions were determined in the filtrate by atomic absorption spectrometry. By the treatment of the loaded resin with 4M HNO3, it was possible to remove completely the Cu(II) ions. The retention properties of the resins were studied for trace metal ions present in the natural seawaters. Both resins showed a high affinity for Cd(II) when the natural seawater contained Cu(II) and Cd(II). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2908–2916, 2004

Preparation and adsorption properties of resins containing amine, sulfonic acid, and carboxylic acid moieties

AbstractCompletely water‐insoluble resins containing amine, carboxylic acid, and sulfonic acid as ligand groups were synthesized by radical polymerization in solution. The yield was higher than 97%. The resins were characterized by FTIR spectroscopy and thermal analysis. The metal ion retention properties at different pH values were investigated by a batch method. Metal ions studied were: Cu(II), Cd(II), Zn(II), Hg(II), Pb(II), and Cr(III). The metal ion binding ability depended strongly on the pH. The retention properties were also tested under competitive conditions. Elution of the metal ion was investigated in acid medium at different concentrations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 700–705, 2003

Ultrafiltration of metal ions by water-soluble chelating poly(N-acryloyl-N-methylpiperazine-co-N-acetyl-?-aminoacrylic acid)

Water-soluble copolymers of N-acryloyl-N-methylpiperazine and N-acetyl-α-aminoacrylic acid were synthesized by radical polymerization. The copolymerization yield ranged between 60 and 97%. The FTIR and NMR spectra demonstrated that the copolymerization occurred. The copolymer composition was determined from 1H-NMR spectra by comparison of methyl groups from both moieties. The copolymers were richest in AAA units. The metal ion retention properties were investigated by the liquid-phase polymer-based retention (LPR) technique at different pH and filtration factors. The affinity for the metal ions depended on the copolymer composition, pH, and filtration factor. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2556–2561, 2002