The effectiveness of the protected amino group on crosslinked chitosans for copper removal and the thermodynamics of interaction at the solid/liquid interface

Machado, Margarete O.; Lopes, Elaine C.N.; Sousa, Kaline S.; Airoldi, Cláudio

doi:10.1016/j.carbpol.2009.02.031

Cited by 41 publications

(16 citation statements)

References 24 publications

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“…Similar results were obtained by Vieira and Beppu 15,19,20 , who studied mercury adsorption on chitosan using static and dynamic methods. Machado et al 21 shows an increase in copper adsorption after glutaradehyde crosslinking reaction, and this fact is attributed to the amount of free amino groups, as there would be less protonated amino groups in the crosslinked matrices. The same effect could be causing the observed results for chromium ions.…”

Section: Resultsmentioning

confidence: 99%

Dynamic adsorption of chromium ions onto natural and crosslinked chitosan membranes for wastewater treatment

et al. 2010

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Water pollution with heavy metals is a matter of major concern for public health and also for natural resource management. The present study investigated the effect of chemical modifications on biopolymeric adsorbents (based on chitosan membranes) for chromium removal using fixed-bed dynamic adsorption technique. Parameters such as flow rate, initial concentration and crosslinking agents were evaluated, from a practical point-of-view, in order to optimize the adsorption capacity of natural, glutaraldehyde and epichlorohydrin crosslinked chitosan membranes. The adsorption capacity of natural and epiclorohydrin-crosslinked chitosan membranes were very close to each other; however, glutaraldehyde-crosslinked chitosan membranes presented nearly twice the adsorption capacity compared to the other membranes, being the most promising adsorbent in such mass-transfer systems.

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Section: Resultsmentioning

confidence: 99%

Dynamic adsorption of chromium ions onto natural and crosslinked chitosan membranes for wastewater treatment

et al. 2010

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“…The most reactive amino group, located at carbon 2 in the original structure of chitosan, has the ability to immobilize organic chains to attach basic centers. After blocking the active amino center of the precursor structure, the hydroxyl group on carbon 6 is free for the desired reaction and in the next stage, neutralizing the proton leaves the free amino group for a new reaction [14]. Another possibility to reach the same condition is, in principle, to block the amino group with a special reagent and remove it after having reacted carbon 6, to again yield chemically modified chitosan [15], in which the attached basic center on pendant chains are enriched by the free amino group to chelate cations from aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Environmentally benign modified biodegradable chitosan for cation removal

2014

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The biodegradable biopolymer chitosan had its linear structure chemically modified in a two-step reaction, first by exploring the amino reactivity with glycidylmethacrylate, whose intermediate product, containing an aldehyde group, was then reacted with 1,2-ethanedithiol. Chitosan and the synthesized biopolymers were characterized by elemental analyses, infrared spectroscopy, nuclear magnetic resonance of the carbon nucleus in the solid state, X-ray diffractometry, thermogravimetry and scanning electron microscopy, to give a degree of immobilization of 3.00 mmol g -1 . The available basic nitrogen, sulfur and oxygen Lewis centers attached to the enlarged pendant chains enriched the ability of the biopolymer for copper, lead and cadmium sorption from aqueous solution, to give maximum capacities of 2.05 ± 0.01; 2.53 ± 0.02 and 1.88 ± 0.01 mmol g -1 , when compared to chitosan with 1.54 ± 0.33; 1.22 ± 0.04 and 1.12 ± 0.08 mmol g -1 , respectively, using the Langmuir sorption isotherms. Based on the present results, the highest amount of these cation sorptions, especially with lead that is associated with sulfur-cation soft interactions, is dependent directly on not only the presence of long pendant chain attached, but also the availability of favorable Lewis base centers. The experimental data adjusted to the Langmuir, the Freundlich and the Temkin sorption isotherms using linear and non-linear regression methods and are in agreement with the best fit for Langmuir model type I.

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“…Many polymers including the natural polymers have major drawbacks such as poor mechanical properties and rapid degradation which limits their application in the skin and tissue engineering field. Interest in the use of genipin as a crosslinker is on the increase due to the many toxic effects of other chemical crosslinkers such as glutaraldehyde (25), glyoxal (26), epichlorohydrin (27), and formaldehyde (28). Genipin is extracted from the Gardenia jasminoides fruit and is an iridoid glucoside that has been used by the food industry and Chinese traditional medicine as a blue colorant.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Semi-Interpenetrating Polymer Network as a Bioactive Curcumin Film

et al. 2014

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Abstract. This study focused on the synthesis and characterization of a natural polymeric system employing the interpenetrating polymer network (IPN) comprising curcumin as a bioactive. Biopolymers and actives such as chitosan, hypromellose, citric acid, genipin, and curcumin were used to develop an effective, biodegradable, and biocompatible film employed therapeutically as a wound healing platform. The semi-IPN films were investigated for their physicochemical, physicomechanical, and biological properties by quantification by FTIR, DSC, and Young's modulus. Following characterization, an optimum candidate formulation was produced whereby further in vitro and ex vivo studies were performed. Results revealed a burst release occurring at the first hour with 1.1 mg bioactive released when in contact with the dissolution medium and 2.23 mg due to bioactive permeation through the skin, thus suggesting that the lipophilic nature of skin greatly impacted the bioactive release rate. Furthermore, chemical and mechanical characterization and tensile strength analysis revealed that the degree of crosslinking and concentration of polymeric material used significantly influenced the properties of the film.

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The effectiveness of the protected amino group on crosslinked chitosans for copper removal and the thermodynamics of interaction at the solid/liquid interface

Cited by 41 publications

References 24 publications

Dynamic adsorption of chromium ions onto natural and crosslinked chitosan membranes for wastewater treatment

Dynamic adsorption of chromium ions onto natural and crosslinked chitosan membranes for wastewater treatment

Environmentally benign modified biodegradable chitosan for cation removal

Synthesis of a Semi-Interpenetrating Polymer Network as a Bioactive Curcumin Film

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