Influence of the nature of the metal ions on the complexation with chitosan.

Rhazi, Mohammed; Desbrières, Jacques; Tolaimate, A.; Rinaudo, Marguerite; Vottero, P.; Alagui, Abdelhakim; Meray, M. El

doi:10.1016/s0014-3057(02)00026-5

Cited by 279 publications

(142 citation statements)

References 23 publications

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“…Subsequently, adsorption occurs by attraction of molecules to this biopolymer form. Complexes of chitosan and metal ions are most probably formed by the mechanisms of adsorption, ion exchange and chelation [40,43]. Pimentaet al [44] reported that the 0.2% chitosan solution (pH=3.2) has a capacity to reduce dentin microhardness similar to that of 15% EDTA (pH=7.25) representing similar demineralization potential.…”

Section: Discussionmentioning

confidence: 99%

Adhesive strength of self-adhesive resins to lithium disilicate ceramic and dentin: effect of dentin chelating agents

2014

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The aim of this study was to test the effect of different chelating agents on microtensile bond strength (MTBS) of self-adhesive resin cements to dentin. The occlusal surfaces of extracted human mandibular molars (N = 80) were cut horizontally to expose sound dentin. The teeth were randomly divided into four groups (n = 20 per group) and dentin surfaces were conditioned according to one of the following methods: group C: no treatment (control group); group CH: 0.2 % chitosan; group E: 17 % ethylene diamine tetra acetic acid (EDTA) and group P: 25 % polyacrylic acid (PAA). Lithium disilicate glass ceramic (e.max CAD) blocks were cemented to conditioned dentin surfaces with self-adhesive cements (RelyX Unicem or Clearfil SA) and photo-polymerized. Specimens were stored in distilled water at 37°C for 24 h and thermocycled for 6,000 times. The beams were obtained from bonded ceramic-cement-tooth assemblies and were subjected to the MTBS test (1 mm/min). Failure types were analyzed and selected beams were examined under scanning electron microscope. Data (MPa) were analyzed using two-way ANOVA and Tukey's test (P < 0.05). While cement type significantly affected the MTBS results (P < 0.05), no significant difference was observed between the dentin chelating agents (P = 0.785). Interaction terms were not significant (P = 0.114). Control group with no dentin conditioning presented significantly lower results with both cements (RelyX Unicem: 8.1 ± 1.9(a), Clearfil SA: 8 ± 1.6(a)) than those of conditioned groups (19.3 ± 4.2(b)-24.5 ± 5.2(b)) (P < 0.05). Failure types were predominantly adhesive in all groups. Chitosan (2 %), EDTA (17 %) or PAA (25 %) could all be used as dentin chelating agents in conjunction with self-adhesive resin cements tested. Abstract:The aim of this study was to test the effect of different chelating agents on microtensile bond strength (MTBS) of self-adhesive resin cements to dentin. The occlusal surfaces of extracted human mandibular molars (N=80) were cut horizontally to expose sound dentin. The teeth were randomly divided into 4 groups (n=20 per group) and dentin surfaces were conditioned according to one of the following methods: Group C: No treatment (Control group); Group CH: 0.2% chitosan; Group E: 17% ethylene diamine tetra acetic acid (EDTA) and Group P: 25% polyacrylic acid (PAA). Lithium disilicate glass ceramic (e.max CAD) blocks were cemented to conditioned dentin surfaces with self-adhesive cements (RelyX Unicem or Clearfil SA) and photo-polymerized.Specimens were stored in distilled water at 37 o C for 24 hours and thermocycled for 6000 times.The beams were obtained from bonded ceramic-cement-tooth assemblies and they were subjected to the MTBS test (1 mm/min). Failure types were analyzed and selected beams were examined under scanning electron microscope. Data (MPa) were analyzed using two-way ANOVA and Tukey's test (P<0.05). While cement type significantly affected the MTBS results (P<0.05), no significant difference was observed between the dentin chelating agents (...

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Section: Discussionmentioning

confidence: 99%

Adhesive strength of self-adhesive resins to lithium disilicate ceramic and dentin: effect of dentin chelating agents

2014

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“…Copper and zinc partitioning between particulate and dissolved forms is not affected by anaerobic digestion [19], and along the neutral to alkaline range of pH values, both metals bind to solids. Rhazi et al [8] showed that, at a pH above 5.8, the structure of the Cu-chitosan complex predominates {[Cu(-NH2)2] 2+ , 2OH − }. Given the creation of flocs rich in Cu and Zn with the capacity for sieve retention, we expected strong Cu and Zn removal despite the low efficiency of gravity drainage to retain small metal-rich particles in solids.…”

Section: Nutrient (N P K) and Metal (Cu And Zn) Content Of Producedmentioning

confidence: 99%

“…Due to free amine function, chitosan can chelate transition metal ions, such as those of Cu and Zn, making it quite suitable for water treatment and seawater metal recovery. Chitosan selectivity for transition metals depends on the cation considered, and great affinity has been demonstrated for divalent Cu, Mercury (Hg), Zn, Cadmium (Cd), Nickel (Ni), Calcium (Ca), and Cobalt (Co) [8].…”

Section: Separation Efficiency Of Centrifugation After Chitosan Additionmentioning

confidence: 99%

“…The addition of chitosan can be a solution for reaching separation objectives of producing a value product to be transported [20] and further used as Cu and Zn fertilizer. A study by Rhazi et al (2002) [8] indicated that the effectiveness of chitosan metallic ion fixation is more pronounced when the chitosan is applied as a film rather than as a powder. Nonetheless, Cu is the most complex among the metal ions, regardless of the chitosan structure [8].…”

Section: Separation Efficiency Of Centrifugation After Chitosan Additionmentioning

confidence: 99%

“…Chitosan is one of the most promising natural flocculants due to the presence of primary amino groups that provide sites for various side groups to attach [7]. The capacity of chitosan to form complexes with metallic ions has been demonstrated [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Centrifugation of Digestate: The Effect of Chitosan on Separation Efficiency

et al. 2017

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Mechanical separation of co-digestate removes dry matter (DM) and phosphorous (P) from digestate effectively but is less capable at removing nitrogen (N) and potash (K). Adding flocculants can enhance separator efficiency. However, information on the use of chitosan as flocculant for co-digestate and its effects on amended slurry application to soil is scarce. This study undertook a series of trial and error tests to identify the optimal chitosan dose to be applied to co-digestate. Four chitosan doses were evaluated: 120 (Dose 1), 240 (Dose 2), 360 (Dose 3), and 480 (Dose 4) mL L −1 of co-digestate. After optimal dose application, centrifugation was employed to separate the co-digestate (centrifugation tests). We used simple separation indices to evaluate the effectiveness of chitosan addition prior to centrifuge usage. Dose optimization tests results indicated that incremental doses of chitosan had no effect (p > 0.05) on total N and it decreased (p < 0.05) total P removal to solids. Dose 3 showed a superior effect based on the physical characteristics evaluated and on the DM content of the fractions produced. Centrifugation tests results showed chitosan increased (p < 0.05) centrifugation efficiency for K, copper (Cu), and zinc (Zn) (75, 36, and 51%, respectively) and had no effect on total N or P. The major findings show that the use of natural and relatively cheap polymer chitosan improves the efficacy of co-digestate centrifugation with respect to K, Cu, and Zn, lowering their load to arable land once a solid fraction is applied.

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Polysaccharides

Rinaudo

2005

Kirk-Othmer Encyclopedia of Chemical Technology

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This article is a short review on polysaccharides based on their recognized applications. The main techniques for polysaccharides characterization are discussed. Cellulose and starch are examined as well as their main derivatives. It is shown how the three‐dimensional (3D) structure influences the distribution of the substituents and the physical properties. Hemicelluloses, pectins, galactomannans, and glucomannans are briefly described. The main source of each of these polymers is presented. Chitin and chitosan are described before introducing the microbial polysaccharides. Bacterial polysaccharides are now developed widely due to the great number of new structures available. The main characteristics of these stereoregular polysaccharides are given.

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Influence of the nature of the metal ions on the complexation with chitosan.

Cited by 279 publications

References 23 publications

Adhesive strength of self-adhesive resins to lithium disilicate ceramic and dentin: effect of dentin chelating agents

Adhesive strength of self-adhesive resins to lithium disilicate ceramic and dentin: effect of dentin chelating agents

Centrifugation of Digestate: The Effect of Chitosan on Separation Efficiency

Polysaccharides

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