Macroreticular Chelating Resins Research Articles

Poly(N-hydroxymethyl acrylamide-co-acrylic acid) and poly(N-hydroxymethyl acrylamide-co-acrylamidoglycolic acid): synthesis, characterization, and metal ion removal properties

Macroreticular chelating resins containing carboxylic groups, poly(N-hydroxymethyl acrylamide-co-acrylic acid) P(HMA-co-AA) and poly(N-hydroxymethyl acrylamide-co-2-acrylamido glycolic acid) P(HMA-co-AGA) were synthesized by solution radical polymerization with ammonium persulfate as initiator and N,N′-methylene-bis-acrylamide as cross-linking reagent. The polymerization yield was 98.9 and 91.9% for P(HMA-co-AA) and P(HMA-co-AGA), respectively. The retention properties were studied under competitive and noncompetitive conditions by batch equilibrium procedure for the following metal ions: Cd(II), Cr(III), Zn(II), Pb(II), and Hg(II). The effects of pH, time, temperature, and initial ion concentration on adsorption were investigated. The resins showed a significant ability to retain Pb(II), greater than 79%, at pH 5.

Adsorption Behavior of Metal Ions by Amidoxime Chelating Resins

AbstractIn this work, the acrylonitrile (AN) – divinylbenzene (DVB) –methylacrylate (MA) resin was synthesized via suspension polymerization in the presence of toluene as diluent, and benzoylperoxide (BPO) as initiator. The effect of MA, toluene and alkaline treatment on the exchange capacity of the resin were investigated. The results showed that the anion exchange capacity decreased with an increase in the amount of MA, while alkaline treatment had no significant effect. Also, the cation exchange capacity increased with an increase in the amount of hydrophilic agent and reached a maximum point. The sorption equilibrium was achieved relatively fast within 40 mins, and the resin exhibited affinity towards lead (II), copper (II) and in particular uranium (VI). The adsorption of uranium was directly depended up on the pH value. Furthermore, the macroreticular chelating resin, containing amidoxime group had higher adsorption of uranium (VI) in comparison to other metal ions studied. Finally, the alkaline treatment enhanced the potential for much faster adsorption characteristics and the highly porous chelating resin provided a more favorable pore structure for the rapid rate of diffusion of metal ions.

Adsorption properties of amidoxime resins for separation of metal ions from aqueous systems

In this study, the acrylonitrile (AN)–divinylbenzene (DVB)–methylacrylate (MA) resin was synthesized via suspension polymerization in the presence of toluene as diluent, and benzoylperoxide (BPO) as initiator. The effects of MA as a hydrophilic agent and toluene as a diluent on the anion and cation exchange capacity of the synthesized amidoxime resins were investigated before and after alkaline treatment. The results showed that the anion exchange capacity decreased with an increase in the amount of MA while alkaline treatment had no significant effect. Also, the cation exchange capacity increased with an increase in the amount of hydrophilic agent and reached a maximum point. The sorption equilibrium was achieved relatively fast within 40 min, and the resin exhibited affinity towards lead (II), copper (II) and in particular U(VI), and the order of adsorption affinity were UO 2 2 + > Pb 2+ ≫ Co 2+ > Cu 2+ ≫ Cd 2+. The adsorption of uranium was directly depended up on the pH value. Furthermore, the macroreticular chelating resin, containing amidoxime group had higher adsorption of uranium (VI) than other metal ions studied. Finally, the alkaline treatment enhanced the potential for much faster adsorption and the highly porous chelating resin provided a more favorable pore structure for the rapid rate of diffusion of metal ions.

Influence of the morphological structure of macroreticular amidoxime resins on their complexation capacity

Macroreticular chelating resins containing amidoxime groups were synthesized by aqueous suspension copolymerization of acrylonitrile (AN) and divinylbenzene (DVB) and subsequent chemical modification of cyano groups by reaction with hydroxylamine. In the copolymerization, the effects of divinylbenzene proportion and dilution degree on the copolymer pore structure were investigated. Gelatin and calcium carbonate were used as suspension stabilizers and sodium sulphate was added in order to reduce acrylonitrile solubility in water, by salting out effect. The copolymers (AN/DVB) and amidoxime resins (RNH/DVB) obtained were characterized by apparent density, surface area, pore volume, optical appearance, surface morphology and by nitrogen content. The amidoxime resins were finally evaluated in relation to the complexation capacity of copper ion.

Metal ions binding by chelating ligands from new polymer bearing amidoxime functional groups

Chelating polymer materials are mainly used in analytical, industrial and radiochemical laboratories, but only to a limited extent in solving environmental problems. Metal pollution of the environment presents a unique problem, since metals are not subjected to biodegradation. The chelating resins containing amidoxime groups have been playing a vital role in environmental monitoring of toxic trace metals. The amidoxime chelating resins can be used for extraction of toxic metals in the environment and sewage waters. The possibility of uranium recovery from seawater has been studied in many countries, a particularly high number of publications come from Japanese scientists, which contain the synthesis of macroreticular resins bearing amidoxime groups, because of their use in extraction of uranium from seawater. 1‐4 Most of these papers involve the incorporation of a nitrile group into a polymer matrix, followed by the conversion of the nitrile group into an amidoxime group using the alkaline solution of hydroxylamine. Egawa et al. 5 prepared a macroreticular chelating resin containing amidoxime by reacting acrylonitrile-divinyl benzene copolymer with hydroxylamine. Kubota and Shigehisa 6 proposed a new route in which amidoxime groups were prepared by the reaction of cyanoethylcellulose and acrylonitrile grafted cellulose with hydroxylamine. Fetscher 7 described the extraction of metals from dilute solutions by poly(amidoxime) resin derived from fibrous homopolymers and copolymers of acrylonitrile. Divinylbenzene cross-linked poly(acryloamidoxime) resins were obtained and successfully used in the determination of trace metals in natural waters. 8,9 Most of the work centralised on the uranium extraction in sea water by poly(amidoxime) resin. There are very few articles published for transition metal uptake by poly(amidoxime) resin. This may first be introduced by the preparation of poly(amidoxime) chelating resin from polyacrylonitrile (PAN) grafted sago starch. In this report, the PAN grafted copolymer was used as a cheapest starting material to obtain the poly(amidoxime) resin and the binding property of the chelating resin was examined with a series of metal ions. The PAN grafted sago starch was prepared from acrylonitrile monomer and sago starch using the free radical initiating process according to the reaction mechanism suggested by Ceresa. 10 The grafting procedure was described elsewhere. 11 The optimum yield of PAN grafted copolymer at the concentration of ceric ammonium nitrate, acylonitrile, sago starch (AGU, anhydroglucose unit) and sulfuric acid were 9.52 〈 10 ‐3 , 0.506, 0.146 and 0.190 mol/l respectively, as well the reaction temperature and period were 50°C and 90 min, respectively. The conversion of the nitrile group into amidoxime was carried out by the treatment of hydroxylamine in an alkaline medium. According to the mechanism suggested by Schouteden, 12 the reaction of PAN with hydroxylamine is shown in Scheme 1, where P is the backbone polymer.

Synthesis and heavy metal ion adsorptivity of macroreticular chelating resins containing phosphono and carboxylic acid groups

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Preparation and uranyl ion adsorptivity of macroreticular chelating resins containing a pair of neighboring amidoxime groups in a monomeric styrene unit

AbstractA cyanomethylated styrene‐divinylbenzene copolymer was prepared by the reaction of a chloromethylated styrene‐divinylbenzene copolymer with sodium cyanide. A polystyrene‐based macroreticular resin containing a pair of neighboring nitrile groups in each monomeric styrene unit was obtained from the reaction of the cyanomethylated copolymer with 3‐chloropropionitrile under phase transfer conditions. The resin was reacted with hydroxylamine to afford a chelating resin containing a pair of neighboring amidoxime groups in each monomeric styrene unit. The chelating resin showed high adsorption capacity for uranyl ions. It was found that the resin was an effective adsorbent for other heavy metal ions such as Hg2+ and Pb2+.

Studies on selective adsorption resins. XXXIII. Behavior of macroreticular chelating resins containing phosphinic and/or phosphonic acid groups in the adsorption of trivalent lanthanides

AbstractThe effect of the crosslinking and the porosity of the chelating resins containing phosphinic and/or phosphonic acid groups (RSP and RCSP) on uptake of trivalent lanthanides was studied; RSP and RCSP were prepared by hydrolysis of condensation products of phosphorus trichloride with styrene–divinylbenzene copolymer beads (RS) and with chloromethylated RS, respectively. From a series of RSs synthesized by systematically changing the amount of the crosslinker (divinylbenzene) or the porogen (2,2,4‐trimethylpentane), RSPs and RCSPs with different degrees of crosslinking and with different porosities were derived. Measurements of their uptake of La(III), Gd(III), or Yb(III) have clarified that RSP and RCSP with moderately crosslinked highly porous structures exhibit high capacities toward the lanthanides. Using these optimized RSP and RCSP and their respective oxidized derivatives RSPO and RCSPO, the distribution of all lanthanides (III) except for Pm(III) from aqueous hydrochloric acid solutions (0.1–1M) was examined. The distribution of each lanthanide(III) at a given concentration of the acid increases in the order RCSPO ≈ RCSP < RSPO < RSP. Their lanthanide selectivity patterns resemble one another; the selectivity increases with increasing the atomic number of the lanthanides except for the elements from Sm to Ho. In order to illustrate usefulness of these resins in the separation of lanthanides, the chromatographic separation of La(III), Nd(III), and Sm(III) was conducted using columns packed with RCSP. The three lanthanides were successfully separated by the elution with 0.5M hydrochloric acid solution without use of any organic complexing reagents, such as EDTA. © 1994 John Wiley & Sons, Inc.

Recovery of uranium from seawater. X. Pore structure and uranium adsorption of macroreticular chelating resin containing amidoxime groups

AbstractEight types of amidoxime–type resin (RNH) were derived from macroreticular acrylonitrile—divinylbenzene copolymer beads, which were synthesized by varying the amount of polymerization initiator. Although these RNH are similar in chemical properties and physical pore structure, they exhibited different adsorption abilities for uranium. The porous structure of RNH in swollen state was analyzed by gel permeation chromatography in aqueous medium. The calibration curves yielded useful information on the pore structure of RNH in the swollen state and it was recognized that the pore structure in the swollen state is important for the improvement of the adsorption rate.

Removal and recovery of nickel ion in sodium citrate solution with chelating resin containing triethylenetetramine side chain

AbstractRemoval and recovery of nickel ion in sodium citrate solution with the macroreticular chelating resin containing triethylenetetramine side chain was investigated. The resin (RMT) exhibited high affinity for nickel ion in a solution containing 100 mmol/dm3 of sodium citrate over the pH range of 7.4–11.5. The adsorption of nickel ion was above 98%. In the column method, the breakthrough capacity of the RMT for nickel ion was 3.0 g/dm3‐resin, when the solution containing 0.5 mmol/dm3 of nickel (II) nitrate and 100 mmol/dm3 of sodium citrate was passed through the RMT column at a space velocity of 7.5 h−1. The nickel ion adsorbed was eluted by allowing 1 mol/dm3 hydrochloric acid to pass through the column. The recycle of adsorption and elution was found to be satisfactory.

Preparation and uranyl ion adsorptivity of macroreticular chelating resins containing phosphono groups

AbstractMacroreticular copolymer beads were prepared by suspension polymerization of styrene, bis(2‐chloroethyl) vinyl phosphonate (CEVP) and divinylbenzene (DVB) in the presence of toluene as diluent. The bis(2‐chloroethyl) phosphonate groups on the bead surface were converted into phosphono groups by hydrolysis with dilute nitric acid. For the additional enrichment of phosphono groups, the copolymers were phosphorylated at the phenyl rings with phosphorus trichloride in the presence of aluminum chloride and hydrolyzed and oxidized with dilute nitrics acid. The investigations on metal ion chelation characteristics of the bead‐type copolymers revealed that they have very high adsorptivity toward uranyl ions and good chemical resistance under acidic and alkaline media. It was also found that the phosphono group‐containing copolymer beads are effective adsorbents for other heavy metal ions such as Pb2+, Hg2+, Cd2+, and Cu2+.

Studies on Selective Adsorption Resins XXIX. Properties of Macroreticular Chelating Resins Containing Amidoxime Groups from Chloromethylstyrene-Divinylbenzene Copolymer Beads

Macroreticular chelating resins (RCSNHs) containing amidoxime groups were prepared from chloromethylstyrene-divinylbenzene copolymer beads (RCSs). The resins (RCCSNHs) having higher density of amidoxime groups were prepared from chloromethylated RCSs. The influence of specific surface area, pore volume, pore radius and density of amidoxime groups on adsorption ability for metal ions was investigated. Adsorption ability was greatly affected by pore structure of the resins. RCCSNHs showed higher adsorption ability than the corresponding RCSNHs prepared from the same RCSs. The density of amidoxime groups in the resins affected adsorption ability for metal ions.

Removal and recovery of gallium and indium lons in acidic solution with chelating resin containing aminomethylphosphonic acid groups

AbstractRemoval and recovery of gallium and indium ions in acidic solution with the macroreticular chelating resin containing aminomethylphosphonic acid groups was investigated. The resin (RMT‐P) exhibited high affinity for gallium and indium ions in sulfuric acid solution. In the column method, gallium and indium ions in sulfuric acid solution (0.05 or 0.5 mol/dm3) were favorably adsorbed on the RMT‐P when the solution containing 27.6 mg/dm3 of gallium ion or 51.4 mg/dm3 of indium ion was passed through the RMT‐P column at a space velocity of 15 h−1. The gallium and indium ions adsorbed were eluted by allowing 1 mol/dm3 sodium hydroxide or 4 mol/dm3 hydrochloric acid to pass through the column. The proposed resin appears to be useful for the recovery of gallium and indium ions in sulfuric acid solution.

Studies of selective adsorption resins. XXVI. Removal of calcium and magnesium ions in a salt solution with chelating resin containing aminomethylphosphonic acid groups

AbstractRemoval of calcium and magnesium ions in a salt solution with the macroreticular chelating resin containing aminomethylphosphonic acid groups was investigated. The resin (RMT‐P) exhibited high affinity for calcium and magnesium ions in a salt solution containing 200 g/dm3 of sodium chloride. In the column method, calcium and magnesium ions in a salt solution were preferentially absorbed on the RMT‐P, when the salt solution containing 100 mg/dm3 of calcium or magnesium ion was passed through the RMT‐P column at a space velocity of 15 h−1. The calcium and magnesium ions adsorbed were eluted by allowing 1 mol/dm3 hydrochloric acid to pass through the column. The recycle of adsorption and elution was found to be satisfactory.

Studies on Selective Adsorption Resins XXVII. Preparation and Properties of Macroreticular Chelating Resins Containing Amidoxime Groups from Chloromethylstyrene—Divinylbenzene Copolymer Beads

Studies on Selective Adsorption Resins XXVII. Preparation and Properties of Macroreticular Chelating Resins Containing Amidoxime Groups from Chloromethylstyrene—Divinylbenzene Copolymer Beads

Influence of Crosslinking and Porosity on the Uranium Adsorption of Macroreticular Chelating Resin Containing Amidoxime Groups

Abstract Macroreticular chelating resins (RNH) containing amidoxime groups with various degrees of crosslinking were synthesized by using various amounts of divinylbenzene (DVB) or/and poly(ethylene glycol) dimeth-acrylate [ethylene glycol dimethacrylate (IG), diethylene glycol dimethacrylate (2G), triethylene glycol dimethacrylate (3G), tetraethylene glycol dimethacrylate (4G), and nanoethylene glycol dimethacrylate (9G)] as crosslinking reagent. The effects of crosslinking reagents on the pore structure, ion-exchange capacity, swelling ratio, and adsorption ability for uranium of RNH were investigated. The adsorption ability of RNH for uranium was tested by use of natural seawater or U-spiked seawater. RNH-1G samples prepared by using 1G were shown to have macroreticular structures by measuring the specific surface area. RNH-1G had high adsorption ability and good physical stability. Though RNH-4G samples obtained by using 4G had little macroreticular structure (macropore), these resins showed high adsorption ability for uranium on treatment with 0. 1 M NaOH at 30°C for 15 h. RNH-4G was found to have low physical and chemical stability. For the preparation of RNH with effective pore structure for the recovery of uranium, as well as chemical and physical stability, the simultaneous use of DVB and 1G or 4G as crosslinking reagent was examined (abbreviated as RNH-DVB-1G and RNH-DVB-4G). The RNH-DVB-1G showed high adsorption ability for uranium. Repeated use did not cause deterioration of either RNH-DVB-1G or RNH-DVB-4G. RNH-DVB-1G samples with various degrees of crosslinking were prepared, and the uranium recovery of the resins was also investigated by a column method. Although the RNH-DVB-1G samples with the same degree of crosslinking had almost the same content of amidoxime groups, the uranium recovery of each RNH-DVB-1G sample was considerably different and increased by treatment with alkali solution. These results indicate that the adsorption ability of RNH-DVB-1G for uranium in seawater was not only affected by the macropores but also by the micropores formed by swelling of the resins.

Recovery of uranium from seawater V. Preparation and properties of the macroreticular chelating resins containing amidoxime and other functional groups

AbstractWe have synthesized macroreticular chelating resins containing amidoxime groups from acrylonitrile (AN)‐divinylbenzene (DVB)‐alkyl acrylate, alkyl methacrylate, or vinylpyridine (VPy) copolymer beads. It was found that the chelating resin (RNMH)‐containing amidoxime groups prepared from AN‐DVB‐methyl acrylate (MA) indicated the highest adsorption ability for uranium in seawater. Hydroxamic acid and carboxylic groups in addition to amidoxime groups were formed during the reaction of the copolymer beads with a methanol solution of hydroxylamine. The adsorption ability for uranium was greatly influenced by the physical pore structure (macropore) and the pore structure formed by the swelling(micropore). RNMH (RNMH10‐10) prepared with 10 mol% of DVB and 10 mol% of MA had the highest adsorption ability and physical stability for uranium. On the other hand, improved adsorption ability for uranium was not observed in the case of the macroporous resins (RNPyH) prepared by the copolymerization of VPy as the basic component. After seawater was passed through the column packed with RNMH10‐10 at a space velocity (SV) of 180 h−1 (up‐flow) for 10 days, the amount of uranium adsorbed on the resin was about 100 mg/dm3‐R and 260 mg/kg‐R.

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

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

Recovery of uranium from sea water. IV. Influence of crosslinking reagent of the uranium adsorption of macroreticular chelating resin containing amidoxime groups

AbstractMacroreticular chelating resins (RNH) containing amidoxime groups with various degrees of crosslinking were synthesized by using various amounts of ethyleneglycol dimethacrylate (1G), dimethyleneglycol dimethacrylate (2G), triethyleneglycol dimethacrylate (3G), tetraethyleneglycol dimethacrylate (4G), and nanoethyleneglycol dimethacrylate (9G) as crosslinking reagent. The effect of crosslinking reagents on the pore structure, ion exchange capacity, swelling ratio, and adsorption ability for uranium of RNH was investigated. RNH (RNH–1G) prepared by using 1G were showed to have macroreticular structures by the measure of specific surface area. RNH–1G had the high adsorption ability and physical stability. Though RNH (RNH–4G) obtained by using 4G have little macroreticular structure (macropore), these resins showed the high adsorption ability for uranium by the treatment with 0.1 mol dm−3 NaOH at 30°C for 15 h (alkali treatment). These results suggest that the formation of not only the favorable macropore but also the micropore is important for the effective recovery of uranium in sea water, whereas RNH–4G was defined to be low physical and chemical stability. For the preparation of RNH which have effective pore structure for the recovery of uranium, chemical, and physical stability, the simultaneous use of divinylbenzene (DVB) and 1G or 4G as crosslinking reagent was examined (abbreviated as RNH–DVB–1G and RNH–DVB–4G). The specific surface area of RNH–DVB–1G increased with an increase of 1G used. These RNH–DVB–1G have been shown the high adsorption ability for uranium. On the other hand, the specific surface area and adsorption ability for uranium of RNH–DVB–4G decreased with an increase of 4G used. Repeated use did not cause the deterioration of both RNH–DVB–1G and RNH–DVB–4G. This result suggests that the simultaneous use of DVB and 1G or 4G contributed the improvement of chemical and physical stability. In particular, RNH–DVB–1G has the effective macropore and micropore for the recovery of uranium.

Studies of selective adsorption resins. XXV. Preparation of macroreticular chelating resins containing aminomethylphosphonic acid groups from methyl methacrylate/divinylbenzene copolymer beads and their adsorption capacity

Macroreticular chelating resins containing aminomethylphosphonic acid groups were prepared by reaction of methyl methacrylate/divinylbenzene copolymer beads with triethylenetetramine, followed by the reaction of the products with phosphorous acid and formaline. The adsorption capacities of this resin for Cu2+, Pb2+, Zn2+, Ni2+, Co2+, Ca2+, and Mg2+ were determined at various pH values. The order of chelate stability for the resin was Cu2+ > Pb2+ > Zn2+ > Ni2+ > Co2+ > Ca2+ > Mg2+. Copper, nickel, zinc, calcium, and magnesium ions can be eluted with 1 mol dm−3 hydrochloric acid. The proposed resin appears to be useful for the removal of Ca2+ and Mg2+ from salt solution.