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Burkhanova, N. D.; Yugai, S. M.; Pulatova, Kh. P.; Nikononvich, G. V.; Milusheva, R. Yu.; Воропаева, Н. Л.; Рашидова, С. Ш.

doi:10.1023/a:1002880411320

Cited by 30 publications

(12 citation statements)

References 1 publication

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“…The changes that occurred on the internal structure of the prepared hydrogel could be investigated using X-ray diffraction techniques. The X-ray diffraction pattern of chitosan (Figure 4) demonstrated two peaks, assigned to its amorphous and crystalline sections at the diffraction angles (2θ) 10° and 20°, respectively [32]. This can be ascribed to the existence of numerous OH and NH2 functional groups with high polarity, which allow for the formation of potent intra-and intermolecular hydrogen bonds.…”

Section: X-ray Diffraction Of the O-cm-chitosan Hydrogelmentioning

confidence: 99%

Adsorption Behavior of Methylene Blue Dye by Novel CrossLinked O-CM-Chitosan Hydrogel in Aqueous Solution: Kinetics, Isotherm and Thermodynamics

2021

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The chemical cross-linking of carboxymethyl chitosan (O-CM-chitosan), as a method for its modification, was performed using trimellitic anhydride isothiocyanate to obtain novel cross-linked O-CM-chitosan hydrogel. Its structure was proven using FTIR, XRD and SEM. Its adsorption capacity for the removal of Methylene Blue (MB) dye from aqueous solution was studied. The effects of different factors on the adsorption process, such as the pH, temperature and concentration of the dye, in addition to applications of the kinetic studies of the adsorption process, adsorption isotherm and thermodynamic parameters, were studied. It was found that the amount of adsorbed MB dye increases with increasing temperature. A significant increase was obtained in the adsorption capacities and removal percentage of MB dye with increasing pH values. An increase in the initial dye concentration increases the adsorption capacities, and decreases the removal percentage. It was found that the pseudo-second-order mechanism is predominant, and the overall rate of the dye adsorption process appears to be controlled by more than one step. The Langmuir model showed high applicability for the adsorption of MB dye onto O-CM-chitosan hydrogel. The value of the activation energy (Ea) is 27.15 kJ mol−1 and the thermodynamic parameters were evaluated. The regeneration and reuse of the investigated adsorbent was investigated.

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Section: X-ray Diffraction Of the O-cm-chitosan Hydrogelmentioning

confidence: 99%

Adsorption Behavior of Methylene Blue Dye by Novel CrossLinked O-CM-Chitosan Hydrogel in Aqueous Solution: Kinetics, Isotherm and Thermodynamics

2021

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“…This observation was in accordance with many previous studies. A peak at a 2θ of approximately 10.2° corresponded to hydrated crystals, and the one around a 2θ of 19.8° belonged to anhydrous crystals because of the intermolecular and intramolecular hydrogen bonding of CS . After radiation‐induced grafting [Figure (B‐b–d)], the basic diffraction peaks were maintained, but some peak intensities changed considerably, and a new peak evidently appeared.…”

Section: Resultsmentioning

confidence: 99%

Poly(ethylene glycol) methyl ether methacrylate‐graft‐chitosan nanoparticles as a biobased nanofiller for a poly(lactic acid) blend: Radiation‐induced grafting and performance studies

Kongkaoroptham

Piroonpan

Hemvichian³

et al. 2015

J of Applied Polymer Sci

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In this study, we aimed to modify chitosan (CS) as a novel compatible bio-based nanofiller for improving the compatibility including the thermal and mechanical properties of poly(lactic acid) (PLA). The modification of CS with poly(ethylene glycol) methyl ether methacrylate (PEGMA) was done by radiation-induced graft copolymerization. The effects of the dose rate, irradiation dose, and PEGMA concentration on the degree of grating (DG) were investigated. The chemical structure, packing structure, thermal stability, particle morphology, and size of the PEGMA-graft-chitosan nanoparticles (PEGMA-graft-CSNPs) were characterized by fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and transmission electron microscopy. The compatibility of the PEGMA-graft-CSNP/PLA blends was also assessed by field emission scanning electron microscopy. The PEGMAgraft-CSNPs exhibited a spherical shape with the DG and particle sizes in the ranges of 3-145% and 35-104 nm, respectively. The PEGMA-graft-CSNPs showed compatible with PLA because of the grafted PEGMA segment. A model case study of the PEGMA-graft-CSNP/PLA blend demonstrated the improvement not only the compatibility but also thermal stability flexibility, and ductility of PLA.

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“…X-ray diffractometry was used to explore the inner structures of the modified chitosan derivatives and their X-ray diffraction patterns were shown in Figure 3. There were two broad peaks in chitosan appeared near to 2θ = 10 • and 20 • which were attributable to its amorphous and crystalline regions, respectively [29]. This can be ascribed to the formation of the hydrogen bonds along its chains due to its possession of a great number of hydroxyl and amino groups.…”

Section: Powder X-ray Diffraction Of Ccs Adsorbentmentioning

confidence: 97%

Kinetics, Isotherm and Thermodynamic Studies for Efficient Adsorption of Congo Red Dye from Aqueous Solution onto Novel Cyanoguanidine-Modified Chitosan Adsorbent

2021

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Novel Cyanoguanidine-modified chitosan (CCs) adsorbent was successfully prepared via a four-step procedure; first by protection of the amino groups of chitosan, second by insertion of epoxide rings, third by opening the latter with cyanoguanidine, and fourth by restoring the amino groups through elimination of the protection. Its structure and morphology were checked using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The adsorption capacity of CCs for Congo Red (CR) dye was studied under various conditions. It decreased significantly with the increase in the solution pH value and dye concentration, while it increased with increasing temperature. The adsorption fitted to the pseudo-second order kinetic model and Elovich model. The intraparticle diffusion model showed that the adsorption involved a multi-step process. The isotherm of CR dye adsorption by CCs conforms to the Langmuir isotherm model, indicating the monolayer nature of adsorption. The maximum monolayer coverage capacity, qmax, was 666.67 mg g−1. Studying the thermodynamic showed that the adsorption was endothermic as illustrated from the positive value of enthalpy (34.49 kJ mol−1). According to the values of ΔG°, the adsorption process was spontaneous at all selected temperatures. The value of ΔS° showed an increase in randomness for the adsorption process. The value of activation energy was 2.47 kJ mol−1. The desorption percentage reached to 58% after 5 cycles. This proved that CCs is an efficient and a promising adsorbent for the removal of CR dye from its aqueous solution.

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Cited by 30 publications

References 1 publication

Adsorption Behavior of Methylene Blue Dye by Novel CrossLinked O-CM-Chitosan Hydrogel in Aqueous Solution: Kinetics, Isotherm and Thermodynamics

Adsorption Behavior of Methylene Blue Dye by Novel CrossLinked O-CM-Chitosan Hydrogel in Aqueous Solution: Kinetics, Isotherm and Thermodynamics

Poly(ethylene glycol) methyl ether methacrylate‐graft‐chitosan nanoparticles as a biobased nanofiller for a poly(lactic acid) blend: Radiation‐induced grafting and performance studies

Kinetics, Isotherm and Thermodynamic Studies for Efficient Adsorption of Congo Red Dye from Aqueous Solution onto Novel Cyanoguanidine-Modified Chitosan Adsorbent

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