Direct ionization and solubility of chitosan in aqueous solutions with acetic acid

Giraldo, Juan D.; Rivas, Bernabé L.

doi:10.1007/s00289-020-03172-w

Cited by 15 publications

(6 citation statements)

References 65 publications

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“…At the sorption pH value, the chitosan-PVA composite has a protonation degree close to 85%, although to know precisely its acid-base behaviour as a polyelectrolyte, it would be necessary to apply the Henderson-Hasselbalch equation as stated by Giraldo and Rivas (2021). Under the adsorption conditions of this study, metal cations are adsorbed through a chelation mechanism on amino groups, according to the one reported previously by Jin and Bai (2002).…”

Section: Freundlich Modelmentioning

confidence: 85%

Treatment of a mining water effluent for the sorption of heavy metal ions using polymer composite beads in a continuous column

Arenas‐Flores

Almeida‐Escalante

Conejo-Flores

et al. 2021

Water & Environment J

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The performance of novel chitosan-poly(vinyl alcohol) gel beads was evaluated removing lead, cadmium and chromium from mining-influenced groundwater (MIGW) under hydrodynamic conditions employing column sorption experiments. To elicit the efficiency of the synthesized materials, the sorbent bed height within the packed column and volumetric flow were varied; the column configuration was changed using packed and fluidized arrangements. The fluidized bed configuration presented higher sorption efficiency for Pb, Cd and Cr ions than the fixed bed configuration: 78%, 52% and 62% against 60%, 35% and 37%. The packed bed data were processed using the Clark, Dose-Response, Yoon-Nelson and Woldborska models. The best fitting was obtained with the Dose-Response model. The experimental output confirmed the effective reduction of the harmful metals in MIGW at a very short breakthrough time from 3 to 15 min, which is strategic due to the global effects on both human health and environment.

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Section: Freundlich Modelmentioning

confidence: 85%

Treatment of a mining water effluent for the sorption of heavy metal ions using polymer composite beads in a continuous column

Arenas‐Flores

Almeida‐Escalante

Conejo-Flores

et al. 2021

Water & Environment J

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“…), the CS chains are tightly packed due to the intrinsic tendency of the polymer to aggregate through van der Waals forces inherent to functional groups in its molecular structure. Even in a slightly acidic medium, although some chains may be solvated, the vast majority are expected to still form packaged insoluble structures (aggregates) whose ionized amine groups are present in a high fraction on their surfaces (Giraldo and Rivas 2021). Moreover, the presence of Clcounterions from the CS solvent (HCl) can impair the long-range organization within the CS molecules by immobilizing the hydration water, which is an additional cause of of}defects}(voids) formation within the structure (Gartner et al 2011).…”

Section: Morphologymentioning

confidence: 99%

High oxygen barrier chitosan films neutralized by alkaline nanoparticles

Jančič

Božič²,

Hribernik

et al. 2021

Cellulose

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The most frequent neutralisation procedure, applied on chitosan (CS) films includes treatment with NaOH base. Such treatment endows CS films with stability in water, yet, same can significantly decrease the film performance. In the present paper, we investigate Mg(OH)2 nanoparticles as a neutralisation agent for CS solutions followed by casting into films. This is combined and compared with classical casting and film drying from non-neutralized solutions followed by NaOH treatment after film formation. The influence on the properties of resulting films is investigated in detail and large differences are found for structure and barrier properties. The stable, opaque-to-transparent CS films (depending on Mg(OH)2 content and post-treatment) were obtained by facile casting method of neat CS or CS–Mg(OH)2 dispersions, in the complete absence of cross-linkers and plasticizers. FTIR data demonstrate the Mg(OH)2 and NaOH deprotonation effect, and strongly suggest intensive H-bonding interaction between CS and Mg(OH)2. X-ray photoelectron spectroscopy showed differences in the hydroxide content and protonation of CS nitrogen. The reduction of surface roughness and increase of homogeneity, the tensile strength and elongation, as well as thermal stability and excellent oxygen barrier properties were measured for CS enclosing the Mg(OH)2 nanoparticles. Further treatment with 1 M NaOH causes re-packing of CS polymer chains, improving the crystallinity and water vapour barrier properties, degrading the mechanical properties by increasing the films brittleness and increasing the char formation due to reduced thermal stability. Graphic abstract

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“…The pKa of chitosan varies from 6.2 to 6.5 depending on its molecular weight and degree of deacetylation (Wang et al., 2006). Chitosan is soluble at acidic pH (for example a 1% acetic acid solution with pH ∼3), but less soluble in water or common physiological buffers (Giraldo & Rivas, 2020). Acidic solutions facilitate the protonation of chitosan, thereby eliciting electrostatic repulsion of each chitosan molecule that results in solvation of this cationic polymer and non‐Newtonian fluidic behaviour (Giraldo & Rivas, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Chitosan is soluble at acidic pH (for example a 1% acetic acid solution with pH ∼3), but less soluble in water or common physiological buffers (Giraldo & Rivas, 2020). Acidic solutions facilitate the protonation of chitosan, thereby eliciting electrostatic repulsion of each chitosan molecule that results in solvation of this cationic polymer and non‐Newtonian fluidic behaviour (Giraldo & Rivas, 2020). By virtue of chitosan's high positive charge it may be able to interact with the negatively‐charged membranes of EVs to facilitate their isolation (Deregibus et al., 2016); moreover, chitosan may form a high‐molecular weight complex with EVs that permits EV isolation using low‐speed centrifugation.…”

Section: Introductionmentioning

confidence: 99%

The polysaccharide chitosan facilitates the isolation of small extracellular vesicles from multiple biofluids

Kumar

Dhadi

Mai

et al. 2021

J of Extracellular Vesicle

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Several studies have demonstrated the potential uses of extracellular vesicles (EVs) for liquid biopsy‐based diagnostic tests and therapeutic applications; however, clinical use of EVs presents a challenge as many currently‐available EV isolation methods have limitations related to efficiency, purity, and complexity of the methods. Moreover, many EV isolation methods do not perform efficiently in all biofluids due to their differential physicochemical properties. Thus, there continues to be a need for novel EV isolation methods that are simple, robust, non‐toxic, and/or clinically‐amenable. Here we demonstrate a rapid and efficient method for small extracellular vesicle (sEV) isolation that uses chitosan, a linear cationic polyelectrolyte polysaccharide that exhibits biocompatibility, non‐immunogenicity, biodegradability, and low toxicity. Chitosan‐precipitated material was characterized using Western blotting, nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and relevant proteomic‐based gene ontology analyses. We find that chitosan facilitates the isolation of sEVs from multiple biofluids, including cell culture‐conditioned media, human urine, plasma and saliva. Overall, our data support the potential for chitosan to isolate a population of sEVs from a variety of biofluids and may have the potential to be a clinically amenable sEV isolation method.

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Direct ionization and solubility of chitosan in aqueous solutions with acetic acid

Cited by 15 publications

References 65 publications

Treatment of a mining water effluent for the sorption of heavy metal ions using polymer composite beads in a continuous column

Treatment of a mining water effluent for the sorption of heavy metal ions using polymer composite beads in a continuous column

High oxygen barrier chitosan films neutralized by alkaline nanoparticles

The polysaccharide chitosan facilitates the isolation of small extracellular vesicles from multiple biofluids

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