Crosslinked Chitosan Resin Research Articles

Adsorption behavior of uranium(VI) and other ionic species on cross-linked chitosan resins modified with chelating moieties

Cross-linked chitosan resins with catechol (catechol-type chitosan, type 1 and type 2), iminodiacetic acid (IDA-type chitosan), iminodimetylphosphonic acid (IDP-type chitosan), phenylarsonic acid (phenylarsonic acid-type chitosan), or serine (serine-type chitosan) were prepared for the collection and concentration of uranium(VI). The adsorption behavior of U(VI) and other ionic species, such as metal ions and oxo-acid ions, on the cross-linked chitosan (base material) and chitosan resins modified with chelating moieties was examined using a column procedure. Especially, the catechol-type chitosan (type 2) adsorbed U(VI) at pH 2–7, and selectively collected U(VI) at acidic pH regions by forming a stable chelate with hydroxyl groups of catechol moiety introduced to the chitosan. Also, the adsorption properties of cationic and anionic species present in aquatic media were elucidated. The adsorption ability for U(VI) was in the order: catechol-type chitosan (type 2) > serine-type chitosan > phenylarsonic acid-type chitosan > the others. The catechol-type chitosan (type 2) was useful for the collection and concentration of uranium(VI).

Synthesis and properties of a novel crosslinked chitosan resin modified by l-lysine

This paper reported the synthesis and properties of a novel crosslinked chitosan resin modified by l-lysine (LMCCR). The new chitosan derivative that produced through the reaction between glutaraldehyde semi-crosslinked chitosan and l-lysine, could be considered either as a reactive and functional polymer or a macroporous weak anion exchanger. The chemical structure characterizations of LMCCR performed by FTIR, 13C NMR and X-ray diffractometry illustrated that amino groups in chitosan had participated in the formations of both the Schiff bases (N C) and the acylated side-chains during the synthesis. The micrography and SEM analysis showed that the LMCCR beads were spherical and porous, with a bead size of 800–1000 μm diameter. LMCCR was found to swell rather than dissolved in acidic mediums from its solubility and swelling behaviors experiments. LMCCR showed considerable adsorption properties as a macroporous weak anion exchanger, with the adsorption capacity of 409.24 mg/g, 253.28 mg/g, 59.52 mg/g and 204.12 mg/g for acetic acid, alanine, BSA and Zn 2+, respectively. The immobilized glucose oxidase that immobilized by LMCCR through covalent bonds exhibited a retentive activity of 42.68% and a half-life of 96 days, showing the LMCCR’s good performances and potential applications in enzyme immobilization.

Adsorption Properties of Ionic Species on Cross-linked Chitosans Modified with Catechol and Salicylic Acid Moieties

Catechol-type chitosan resin and salicylic acid-type chitosan resin were easily synthesized for use in estimating the adsorption behavior of 34 elements at pH 1 - 7 in aquatic media. The catechol-type chitosan resin could adsorb Cu(II) at pH 3 - 7, In(III) at pH 4 - 6, Pb(II) and lanthanoids at pH 5 - 7, and U(VI) at pH 4 - 7 more effectively than the salicylic acid-type chitosan resin and the cross-linked chitosan resin (base material). Adsorption ability was in the order: catechol-type chitosan resin > salicylic acid-type chitosan resin > cross-linked chitosan resin.

Synthesis of Chitosan-Based Resins Functionalized with Serine Moiety and Its Application to Determination of Trace Amounts of Uranium by FI/ICP-MS System

Cross-linked chitosan resins possessing serine moiety (serine-type chitosan resins) were synthesized for the collection of trace uranium and the separation of matrices in seawater prior to ICP-MS measurement. The serine moiety has a carboxyl group and an amino group at the β-carbon position of ethanol. The adsorption behavior of trace elements on two types of chitosan resin, coupled with the hydroxyl group of serine (type 1) and with the amino group of serine (type 2), was investigated by using a proposed column procedure. The serine-type chitosan resin (type 1) adsorbed U(VI) over wide pH regions from 2 – 9, and especially could collect U(VI) at acidic pH regions selectively by forming stable chelate with the amino group and the carboxyl group of the serine moiety introduced to chitosan. Further, the flow injection/ICP-MS system was developed for the determination of trace uranium in seawater using a small column packed with the resin. The proposed system could be applied to the uranium analysis.

Adsorption of gold(III), platinum(IV) and palladium(II) onto glycine modified crosslinked chitosan resin

The adsorption of Au(III), Pt(IV) and Pd(II) onto glycine modified crosslinked chitosan resin (GMCCR) has been investigated. The parameters studied include the effects of pH, contact time, ionic strength and the initial metal ion concentrations by batch method. The optimal pH for the adsorption of Au(III), Pt(IV) and Pd(II) was found to range from 1.0 to 4.0 and the maximum uptake was obtained at pH 2.0 for Au(III), Pt(IV) and Pd(II). The results obtained from equilibrium adsorption studies are fitted in various adsorption models such as Langmuir and Freundlich and the model parameters have been evaluated. The maximum adsorption capacity of GMCCR for Au(III), Pt(IV) and Pd(II) was found to be 169.98, 122.47 and 120.39 mg/g, respectively. The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models and an intraparticle diffusion model. The correlation results suggested that the pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Au(III), Pt(IV) and Pd(II) onto GMCCR. Various concentrations of HCl, thiourea and thiourea–HCl solutions were used to desorb the adsorbed precious metal ions from GMCCR. It was found that 0.7 M thiourea–2 M HCl solution provided effectiveness of the desorption of Au(III), Pt(IV) and Pd(II) from GMCCR. The modification of glycine on crosslinked chitosan resin (CCR) was studied by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM).

Adsorption of platinum (IV), palladium (II) and gold (III) from aqueous solutions onto l-lysine modified crosslinked chitosan resin

Crosslinked chitosan resin chemically modified with l-lysine has been used to investigate the adsorption of Pt(IV), Pd(II) and Au(III) from aqueous solutions. Batch adsorption studies were carried out with various parameters, such as initial metal ion concentration, contact time, pH and temperature. The maximum adsorption capacity was found at pH 1.0 for Pt(IV), at pH 2.0 for Au(III) and Pd(II). Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Langmuir isotherm and the maximum adsorption capacity was found to be 129.26 mg/g for Pt(IV), 109.47 mg/g for Pd(II) and 70.34 mg/g for Au(III). The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models. Kinetic data correlated well with the pseudo-second-order kinetic model, indicating that the chemical sorption was the rate-limiting step. Thermodynamic parameters like Gibbs free energy (Δ G°), enthalpy (Δ H°) and entropy (Δ S°) were evaluated by applying the Van’t Hoff equation. The thermodynamic study indicated that the adsorption process is spontaneous and exothermic in nature. The desorption studies were carried out using various reagents. The maximum percent desorption of precious metal ions were obtained when the reagent 0.7 M thiourea–2 M HCl was used.

Adsorption of chromium (VI) on a novel quaternized chitosan resin

AbstractAn inverse emulsion method was used to prepare the chitosan microspheres, which were crosslinked with epichlorohydrin between the hydroxyl groups under protection of amino groups to obtain crosslinked chitosan resin. Further chemical modification with glycidyl trimethylammonium chloride was used to form the quaternary ammonium ion resin. The resin had different adsorption ability for the chromium (VI) in anionic forms from that of the crosslinked chitosan beads. The crosslinked chitosan resin exhibited maximum adsorption for chromium (VI) at pH 3.0 and the adsorption capacity decreased sharply above pH 6, whereas the adsorption capacities of quaternized chitosan resin were significant over pH 3 to 11. The quaternized resin was more efficient than the crosslinked chitosan resin in media of pH above 5. The complete removal of chromium from the solution of K2Cr2O7 was achieved with a column method using the quaternized chitosan resin, which was hard, and the decrease in pressure in the column was small. The breakthrough point of 10.0 mg L−1 chromium in quaternized resin column was 3200 mL g−1 resin greater than 600 mL g−1 resin in the crosslinked chitosan resin column. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 505–510, 2003

Synthesis of Cross-Linked Chitosan Resin Possessing Leucine Moiety for the Column Collection/Concentration of Molybdenum and Determination of Molybdenum by ICP-MS, ICP-AES and GFAAS

Abstract A chitosan resin possessing the leucine moiety (leucine-type chitosan) was newly synthesized by using the chitosan cross-linked with ethylene glycol diglycidyl ether (EGDE) as a basic material. The adsorption behavior of trace amounts of metal ions on the leucine-type chitosan was systematically examined by packing it in a mini-column by ICP-MS (inductively coupled plasma mass spectrometry). Molybdenum was adsorbed on the resin quantitatively and was easily eluted with 1 M nitric acid. The optimized pH range was from 1 to 5, and Mo was collected by the chelation mechanism and/or the anion-exchange mechanism. The method was applied to the determination of Mo in sea and river water samples. A pretreatment with the resin could remove the matrix components in seawater. Preconcentration by 100-fold was accomplished by a column treatment, which had a sufficient concentration to measure trace Mo in river water samples by ICP-AES (inductively coupled plasma atomic emission spectrometry) and GFAAS (graphite furnace atomic absorption spectrometry): LODs with a 100-fold preconcentration by ICP-AES and GFAAS were 0.007 ng mL−1 and 0.009 ng mL−1, respectively, and the RSDs were both within 4.0%.

Investigations on the adsorbents for uremic middle molecular toxins (II)

Chitosan resins, which clinically served as adsorbents in hemo perfusion therapy, were prepared with reversed-phase suspension methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal and glutaraldehyde crosslinked chitosan resins were reduced with NaBH4 afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular toxins and BSA in vitro, all three adsorbents demonstrated a fairly realistic adsorption capability to the model toxins but little to BSA. And the adsorption process reached the equilibrium in a clinically qualified short time. But the adsorption capacities of these adsorbents to the model toxins were quite different. It had been found that with the growing of fatty chain length of crosslinking agent, these adsorbents showed a gradually increased adsorption capacity to the model toxins, and the glutaraldehyde crosslinked chitosan resin behaved best.

Studies on synthesis and adsorption properties of chitosan cross-linked by glutaraldehyde and Cu(II) as template under microwave irradiation

A series of cross-linked chitosan resins have been synthesized by forming chitosan coordination of Cu(II) as template in dilute acetic acid solutions under microwaves irradiation, then reacting the Cu(II)–chitosan complex with glutaraldehyde as cross-linking agent under microwave irradiation, and finally removing off the Cu(II ) with dilute acid. The adsorption capacity and selectivity of the cross-linked chitosan for Cu 2+, Ni 2+ and Co 2+ have also been investigated. The experimental results show that these resins obtained have better adsorption capacity for Cu 2+ than Ni 2+ and Co 2+, very good stability and reusability in acidic solutions.

Investigations on the adsorbents for uremic middle molecular toxins (II) —— Influences of crosslinking agent chain length on the adsorption capacities of crosslinked chitosan adsorbents

Chitosan resins, which clinically served as adsorbents in hemoperfusion therapy, were prepared with reversed-phase suspension methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal and glutaraldehyde crosslinked chitosan resins were reduced with NaBH4 afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular toxins and BSA in vitro, all three adsorbents demonstrated a fairly realistic adsorption capability to the model toxins but little to BSA. And the adsorption process reached the equilibrium in a clinically qualified short time. But the adsorption capacities of these adsorbents to the model toxins were quite different. It had been found that with the growing of fatty chain length of crosslinking agent, these adsorbents showed a gradually increased adsorption capacity to the model toxins, and the glutaraldehyde crosslinked chitosan resin behaved best.

Adsorption of Bilirubin by Amine-Containing Crosslinked Chitosan Resins

Crosslinked chitosan resin, which has good blood compatibility, was prepared by crosslinking chitosan solution with glutaraldehyde. Polymeric adsorbents for bilirubin have been synthesized by chemical modification of crosslinked chitosan resins with di-, tri-, tetra-, and pentammines. The adsorption of bilirubin on the adsorbents was investigated in detail. The results indicated that electrostatic interaction and hydrophobic interactions are the main driving forces for the adsorption. Compared with crosslinked chitosan resin, the functionalized chitosan beads have higher adsorption capacity for unconjugated and conjugated bilirubin.

Selective Adsorption of Metal Ions on Novel Chitosan-Supported Sulfonic Acid Resin.

A novel chitosan-supported sulfonic acid resin modified by propane sultone was prepared and the adsorption characteristics of metal ions are examined by using a crosslinked chitosan-supported sulfonic acid resin (PSC) and a crosslinked chitosan resin (CLC).In the low acidity region, the metal selectivity of PSC is similar to that of CLC. This suggested that the selectivity of PSC was attributed not to the sulfonate group but to the chitosan matrix. The role of the sulfonate is believed to be enriching the metal concentration in the neighborhood of the chitosan matrix. At the same time, since the hydrogen ion is also enriched in a thin layer near the surface of the main, the characteristic adsorption curves of PSC shift to the high pH region compared with those of CLC. The adsorption equilibrium constants of metal ion on PSC and CLC are evaluated. The maximum adsorption capacity for PSC in the case of adsorption of copper is 1.6 times that of CLC. On the other hand, in the high acidity region, the maximum adsorption capacity for PSC in the case of adsorption of palladium is lower than that for CLC because of steric hindrance.

A new type of ALSS — the preparation of crosslinked chitosan resins and its adsorption properties for bilirubin

With chitosan as a raw material, a new type of ALSS-CHP was prepared by the reaction of glutaric dialdehyde with chitosan. This type of resin has high adsorption capacity for bilirubin and good blood compatibility. The adsorption capacity was related to the degree of crosslinking of beads; phosphate buffer concentration; bilirubin concentration; pH value; BSA concentration and the size of resins.