Adsorption Properties For Metal Ions Research Articles

Study of the synthesis of chitosan derivatives containing benzo‐21‐crown‐7 and their adsorption properties for metal ions

AbstractThree new chitosan crown ethers, N‐Schiff base‐type chitosan crown ethers (I, III), and N‐secondary amino type chitosan crown ether (II) were prepared. N‐Schiff base‐type chitosan crown ethers (I, III) were synthesized by the reaction of 4′‐formylbenzo‐21‐crown‐7 with chitosan or crosslinked chitosan. N‐Secondary amino type chitosan‐crown ether (II) was prepared through the reaction of N‐Schiff base type chitosan crown ether (I) with sodium brohydride. Their structures were characterized by elemental analysis, infrared spectra analysis, X‐ray diffraction analysis, and solid‐state 13C NMR analysis. In the infrared spectra, characteristic peaks of CN stretch vibration appeared at 1636 cm−1 for I and 1652 cm−1 for II; characteristic peaks of NH stretch vibration appeared at 1570 cm−1 in II. The X‐ray diffraction analysis showed that the peaks at 2θ = 10° and 28° disappeared in chitosan derivatives I and III, respectively; the peak at 2θ = 10° disappeared and the peak at 2θ = 28° decreased in chitosan‐crown ether II; and the peak at 2θ = 20° decreased in all chitosan derivatives. In the solid‐state 13C NMR, characteristic aromatic carbon appeared at 129 ppm in all chitosan derivatives, and the characteristic peaks of carbon in CN groups appeared at 151 ppm in chitosan crown ethers I and III. The adsorption and selectivity properties of I, II, and III for Pd2+, Au3+, Pt4+, Ag+, Cu2+, and Hg2+ were studied. Experimental results showed these adsorbents not only had good adsorption capacities for noble metal ions Pd2+, Au3+, Pt4+, and Ag+, but also high selectivity for the adsorption of Pd2+ with the coexistence of Cu2+ and Hg2+. Chitosan‐crown ether II only adsorbs Hg2+ and does not adsorbs Cu2+ in an aqueous system containing Pd2+, Cu2+, and Hg2+. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1886–1891, 2002

Studies of syntheses and adsorption properties of chelating resin from thiourea and formaldehyde

AbstractChelating resins are useful substances in industry because of their extraordinary adsorption properties for specific metal ions. In this study, a new type of chelating resin is synthesized simply by reaction between thiourea and formaldehyde. The synthetic conditions and the structure of the product are approached and the adsorbing capacities for 11 metal ions, adsorbing rates, and selectivities investigated. The results of the experiments show that the resin has high adsorbing capacities for Ag(I): 13.1 mmol/g, and for Au(III): 6.95 mmol/g. Adsorbing rates are close to 100% in dilute solution. Isothermal adsorbing study reveals that the adsorption is monomolecular layer adsorption process. It is hopeful for the resin to be used for concentrating and retrieving Ag(I) and Au(III) ions from their dilute solutions in industry. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3127–3132, 2001

Development of new chelating hydrogels based on N-vinyl imidazole and acrylonitrile

Copolymers derived from the binary mixture of N-vinyl imidazole (VIm) and Acrylonitrile (AN) monomers have been synthesized by the irradiation of their solution with 60Co- γ rays. Gelation percent–dose graphs were formed, and 80% of gelation (maximum percentage) has been reached at around 14 kGy dose. To impart metal ion adsorption properties, the hydrogels were amidoximated by the reaction of cyano groups on AN with hydroxylamine in aqueous media. Swelling behaviors of hydrogels were investigated before and after amidoximation. Hydrogels had 54% of swelling originally, this ratio reached 220% of swelling after amidoximation. The degree of amidoximation was followed by FT-IR spectroscopy. The structures of copolymers were analyzed spectroscopically and thermally before and after the amidoximation reaction.

Synthesis of sulfhydryl chitin and its adsorption properties for heavy metal ions

This article discusses the preparation of the water-insoluble adsorbent sulfhydryl chitin (s-chitin), by treatment of the chitin with sulfhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis, FTIR spectra analysis and near-IR spectra analysis. We also investigated the adsorption properties of sulfhydryl chitin for CuII, CdII, PbII, CrIII, and NiII. Based on the research results of adsorption capacity, the effect of pH value on adsorption, adsorption kinetics experiments, and selective adsorption experiments were observed. It has been shown that the s-chitin has much better adsorption for PbII, CuII, and CdII than chitin itself. The adsorption capacities of s-chitin for PbII, CuII, and CdII were 108.3, 94.7, and 57.1 mg/g, respectively. It also had good adsorption properties for heavy metal ions. The adsorption capacities were also affected by the acidity of medium. The adsorbed CuII, CdII, and PbII could be eluted by diluted chlorhydric acid. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 151–155, 2000

Synthesis and adsorption properties for metal ions of mesocyclic diamine-grafted chitosan-crown ether

A new type of grafted chitosan-crown ether was synthesized using mesocyclic diamine crown ether as the grafting agent. The C2 amino group in chitosan was protected from the reaction between benzaldehyde and chitosan to form N-benzylidene chitosan (CTB). After reaction with mesocyclic diamine crown ether of the epoxy propane group to give mesocyclic diamine-N-benzalidene chitosan (CTBA), the Schiff base was removed in a dilute ethanol hydrochloride solution to obtain chitosan-crown ether (CTDA). Its structure was confirmed by FTIR spectra analysis and X-ray diffraction analysis. Its static adsorption properties for Pb(II), Cu(II), Cd(II), and Cr(III) were studied. The experimental results showed that the grafted chitosan-crown ether has high selectivity for the adsorption of Cu(II) in the presence of Pb(II), Cu(II), and Cd(II) and its adsorption selectivity is better than that of chitosan. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1255–1260, 2000

Study on chelating resins XXXI syntheses and adsorption properties of a new type of bead resins containing S and N

A new type of bead crosslinked chelating resins containing coordinate atoms N and S were synthesized by the reaction of polyethyleneimine with chloromethylthiirane in suitable sovent at temperature of 20–80°C. These chelating resins exhibited excelent adsorption properties for precious metal ions.

Preparation and adsorption properties of metal ions of crosslinked chitosan azacrown ethers

Preparation and adsorption properties of metal ions of crosslinked chitosan azacrown ethers

Preparation and adsorption properties of metal ions of crosslinked chitosan azacrown ethers

The novel azacrown ether chitosan derivatives (CCAE-I, CCAE-II) were prepared by reaction between crosslinked chitosan with epoxy-activated azacrown ethers. Their structures were confirmed by elemental FTIR spectra analysis and X-ray diffraction analysis. The adsorption and selectivity properties of the crosslinked chitosan azacrown ethers for Pb2+, Cu2+, Cr3+, Cd2+, and Hg2+ were also investigated. The experimental results showed that they have high adsorption capacity for Cu2+, Cd2+, and Hg2+. The adsorption capacity of CCAE-II is higher than CCAE-I for Cd2+ and Hg2+. The selectivity properties of CCAE are better than chitosan and crosslinked chitosan. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3053–3058, 1999

Synthesis and adsorption properties for metal ions of crosslinked chitosan acetate crown ethers

Two novel chitosan derivatives—crosslinked chitosan dibenzo-16-c-5 acetate crown ether (CCTS-1) and crosslinked chitosan 3,5-di-tert-butyl dibenzo-14-c-4 diacetate crown ether (CCTS-2)—were synthesized by the reaction of crosslinked chitosan with dibenzo-16-c-5 chloracetate crown ether and 3,5-di-tert-butyl dibenzo-14-c-4 dichloracetate crown ether with the intent of forming polymers that could be used in hazardous waste remediation as toxic metal-binding agents in aqueous environments. Their structures were confirmed with elemental analysis, infrared spectral analysis, and X-ray diffraction analysis. In the infrared spectra of CCTS-1 and CCTS-2, the characteristic peaks of aromatic backbone vibration appeared at 1595 cm−1 and 1500 cm−1; the intensity of the NH and OH stretching vibration in the region of 3150–3200 cm−1 decreased greatly. The X-ray diffraction analysis showed that the peak at 2θ = 20° decreased greatly in CCTS-1 and CCTS-2. The adsorption and selectivity properties of CCTS-1 and CCTS-2 for Pb2+, Cu2+, Cr3+, and Ni2+ were studied. Experimental results showed that the two crosslinked chitosan derivatives had not only good adsorption capacities for Pb2+, Cu2+, but also high selectivity for Pb2+, Cu2+ in the coexistence of Ni2+. For aqueous systems containing Pb2+, Ni2+, or Cu2+, Ni2+, CCTS-1 only adsorbed Pb2+ or Cu2+. For aqueous systems containing Pb2+, Cr2+ and Ni2+, CCTS-2 had high adsorption and selectivity properties for Pb2+. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2069–2074, 1999

Synthesis and adsorption properties for metal ions of crosslinked chitosan acetate crown ethers

Two novel chitosan derivatives—crosslinked chitosan dibenzo-16-c-5 acetate crown ether (CCTS-1) and crosslinked chitosan 3,5-di-tert-butyl dibenzo-14-c-4 diacetate crown ether (CCTS-2)—were synthesized by the reaction of crosslinked chitosan with dibenzo-16-c-5 chloracetate crown ether and 3,5-di-tert-butyl dibenzo-14-c-4 dichloracetate crown ether with the intent of forming polymers that could be used in hazardous waste remediation as toxic metal-binding agents in aqueous environments. Their structures were confirmed with elemental analysis, infrared spectral analysis, and X-ray diffraction analysis. In the infrared spectra of CCTS-1 and CCTS-2, the characteristic peaks of aromatic backbone vibration appeared at 1595 cm−1 and 1500 cm−1; the intensity of the NH and OH stretching vibration in the region of 3150–3200 cm−1 decreased greatly. The X-ray diffraction analysis showed that the peak at 2θ = 20° decreased greatly in CCTS-1 and CCTS-2. The adsorption and selectivity properties of CCTS-1 and CCTS-2 for Pb2+, Cu2+, Cr3+, and Ni2+ were studied. Experimental results showed that the two crosslinked chitosan derivatives had not only good adsorption capacities for Pb2+, Cu2+, but also high selectivity for Pb2+, Cu2+ in the coexistence of Ni2+. For aqueous systems containing Pb2+, Ni2+, or Cu2+, Ni2+, CCTS-1 only adsorbed Pb2+ or Cu2+. For aqueous systems containing Pb2+, Cr2+ and Ni2+, CCTS-2 had high adsorption and selectivity properties for Pb2+. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2069–2074, 1999

Adsorption Properties of Metal Ions onto Sodium Polyacrylate Gel.

Adsorption properties of divalent and trivalent metal ions onto sodium polyacrylate gel are investigated over a range of pH of buffer solutions. It is considered that carboxyl groups in the gel combine with the metal ions according to their charge number stoichiometrically, and the adsorption mechanism is theoretically analyzed on the basis of dissociation equilibrium for monocarboxyl acid. Furthermore, it is found that the adsorption effectiveness factor, being intrinsic to metal ion species, fulfills an important role in order to elucidate the adsorption equilibrium. Consequently, the model equations, which allow quantitative consideration of the adsorption mechanism in these systems, can be derived as a function of the hydrogen ion concentration, which can readily be measured in the outer aqueous solution. The gel adsorption equilibrium of divalent and trivalent metal ions can be explained fairly well by the model.

Adsorption Properties of Trivalent Metal Ions onto Hydrolyzed Polyacrylamide Gel.

In a previous paper (Morohashi et al., 1990), we focused the attention on quantitative consideration of the adsorption mechanism of divalent metal ions onto the hydrolyzed polyacrylamide gel, which was based on the adsorption equilibrium of the metal ions. In this study, adsorption properties of the trivalent metal ions, Fe 3+ , onto the gel were investigated in the buffer solution. It was reported that the relationship between concentration of metal complexes adsorbed and that of hydrogen ions was explained fairly well by a model according to the adsorption equilibrium of the trivalent metal ions.

Relationship between metal ion adsorption and catalytic properties of carbon-supported nickel catalysts

During the preparation of supported metal catalysts, the adsorption of aqueous metal ions is influenced by the intrinsic properties of the support. Any attempt to model this adsorption phenomenon requires at least three elements: the pH-dependent surface charge speciation of the support, the pH-dependent aqueous phase speciation of the precursor ion, and a suitable model to describe the equilibrium exchange reaction. A series of activated carbons derived from a low ash content carbon source was prepared by controlled oxidation using nitric acid. The surface ionization constants for the protonation/de proton ation equilibria of the hydroxyl groups on each carbon were determined assuming a classical Gouy-Chapman diffuse layer. They were found to vary systematically with extent of oxidation. Nickel adsorption data were obtained over a wide range of pH and Ni concentration. Under the conditions of this study, Ni 2+ was the dominant ion. A surface complexation model was employed to test the hypothesis that the model's parameters could be correlated to the results of characterization studies of these Ni/carbon catalysts. Specifically, it was found that the surface stability constant (≈Δ G ads) of the precursor and the point of zero charge of the carbon varied in accordance with results from temperature-programmed reduction and temperature-programmed oxidation. It is proposed that the point of zero charge of the carbon support can serve as a convenient index for the design of carbon-supported metal catalysts with desired catalytic properties.

Adsorption properties of metal ions onto hydrolyzed polyacrylamide gel.

An experimental investigation of the adsorption properties of metal ions onto gel was carried out by using hydrolyzed polyacrylamide gel and copper sulphate, ferrous ammonium sulphate and ferrous sulphate solutions. Considering that carboxyl groups in the gel bond with the metal ions according to their electric charge number, the adsorption properties were examined on the basis of dissociation equilibriums from monocarboxyl to dicarboxyl acid. From theoretical analyses, empirical equations that give the amount of metal ions adsorbed on the gel were obtained. For the adsorption equilibrium of copper and ferrous ions, the amount of ions adsorbed within the gel can be calculated well from the initial and equilibrium concentrations of the metal ions in aqueous phase, the concentrations of hydrogen ions, the weight of the gel and the volume of solution used.

Preparation and properties of resins with adsorption properties for heavy metal ions. Part 5

Strong and weak resins were prepared by crosslinking branched polyethyleneimine with three dihalo-aliphatic derivatives and subsequent N-methylation. All the resins were insoluble in water and common organic solvents. It was found that the N-methylated resins showed the highest adsorption ability for uranium. The morphology and the thermal stability were also examined.

Synthesis of a Dithiocarbamate Chelate Resin and Its Oxidized form and Their Adsorption Properties for Heavy Metal Ions

Abstract A series of macroporous dithiocarbamate chelate resins, III and V, and an oxidized resin, VI, with high adsorption capacity were prepared. The influence of various reaction conditions of amination, dithiocarboxylation, and oxidation were examined. The structure and the conversion of functional groups of resins were confirmed by IR spectra and elemental analysis. The adsorption capacities of Resin II for Hg2+, Cu2+, Zn2+, and Cd2+ are 4.40, 2.44, 1.77, and 1.36 mmol/g, respectively. The adsorption capacities of Resins V and VI for Cu2+. Zn2+, Ni2+, Co3+, Ag+, Hg2+, Cd2+, Pb2+, and Au3+ are 4.07–0.51 and 3.81–0.59 meq ion/g, respectively. The adsorption rate and the influence of pH on the adsorption percentage of the resins for metal ions were examined. Noble metal, transitional metal, and heavy metal ions can be quantitatively adsorbed by the resins. The adsorbed Cu2+, Pb2+, Cd2+, Co3+, and Ni2+ can be quantitatively eluted with 5N HNO3, and the presence of large amounts of Ca2+, Mg2+, Fe3+, and A...