scholarly journals Synthesis of Novel Crosslinked Chitosans with a Higher Fatty Diacid Diglycidyl and Their Adsorption Abilities towards Acid Dyes

2003 ◽  
Vol 21 (5) ◽  
pp. 439-449 ◽  
Author(s):  
Yoshiaki Shimizu ◽  
Atsushi Taga ◽  
Hitoshi Yamaoka
Keyword(s):  
Chemical Structure ◽  
Crosslinking Agent ◽  
Considerable Extent ◽  
Degree Of Substitution ◽  
Acid Orange 7 ◽  
Acid Dyes ◽  
Ph Values ◽  
Crosslinked Chitosan ◽  
Adsorbent Materials ◽  
Dye Molecule

Novel chitosan-based adsorbent materials with a higher fatty diacid diglycidyl as the crosslinking agent were synthesized and the adsorption abilities of the resulting polymers evaluated towards typical acid dyes. The successful formation of a crosslinked structure was confirmed via infrared spectroscopic measurements and the solubility of the polymer towards 10% aqueous solutions of acetic and formic acids determined. At higher dye concentrations, the adsorption abilities of the crosslinked chitosan towards hydrophilic CI Acid Orange 7 and CI Acid Red 1 increased with decreasing degree of substitution. However, at lower dye concentrations, the crosslinked chitosan with the lowest degree of substitution exhibited the lowest adsorption capability. With such hydrophilic acid dyes, the extent of adsorption decreased significantly as the pH of the solution increased. On the other hand, CI Acid Red 138, which contains a dodecyl group in the chemical structure, was adsorbed to a considerable extent even at higher pH values, suggesting hydrophobic interaction between the alkyl group in the dye molecule and the hydrophobic crosslinker.

Terephthalaldehyde as better crosslinking agent in crosslinked chitosan hydrogel for selective removal of anionic dyes

2021 ◽  
Author(s):  
Madhvi Garg ◽  
Navneet Bhullar ◽  
Bharat Bajaj ◽  
Dhiraj Sud
Keyword(s):  
Crosslinking Agent ◽  
Selective Removal ◽  
Synthetic Dyes ◽  
Anionic Dyes ◽  
Chitosan Hydrogel ◽  
Ultrasound Radiation ◽  
Radiation Induced ◽  
Crosslinked Chitosan ◽  
Chitosan Hydrogels ◽  
Crosslinking Agents

The present manuscript reports the ultrasound radiation induced synthesis of grafted chitosan hydrogels (CAAT and CAAG) using terephthalaldehyde/glutaraldehyde as crosslinking agents and its application for removal of synthetic dyes from...

1H-NMR Analysis of Degree of Substitution in N,O-Carboxymethyl Chitosans from Various Chitosan Sources and Types

2012 ◽  
Vol 506 ◽  
pp. 158-161 ◽  
Author(s):  
A. Jaidee ◽  
Pornchai Rachtanapun ◽  
S. Luangkamin
Keyword(s):  
Chemical Structure ◽  
Carboxymethyl Chitosan ◽  
Degree Of Substitution ◽  
Resonance Spectroscopy ◽  
Nmr Analysis ◽  
Reaction Conditions ◽  
H Nmr ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Chitosan Oligomer ◽  
Ft Ir

N,O-Carboxymethyl chitosans were synthesized by the reaction between shrimp, crab and squid chitosans with monochloroacetic acid under basic conditions at 50°C. The mole ratio of reactants was obtained from various reaction conditions of shrimp chitosan polymer and oligomer types. The mole ratio 1:12:6 of chitosan:sodium hydroxide:monochloroacetic acid was used for preparing carboxymethyl of chitosan polymer types while carboxymethyl of chitosan oligomer types were used the mole ratio 1:6:3 of chitosan:sodium hydroxide:monochloroacetic acid. The chemical structure was analyzed by fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnatic resonance spectroscopy (1H-NMR). The FT-IR was used for confirm the insertion of carboxymethyl group on chitosan molecules. The 1H-NMR was used for determining the degree of substitution (DS) of carboxymethylation at hydroxyl and amino sites of chitosans. Carboxymethyl chitosan samples had the total DS of carboxymethylation ranging from 1.0-2.2. The highest of DS of carboxymethylation was from shrimp chitosan oligomer type.

Spatial and Temporal Variability of Surface Snowfall and Snowpack Chemistry in Central Ontario

1985 ◽  
Vol 7 ◽  
pp. 185-190 ◽  
Author(s):  
R.S. Schemenauer ◽  
P.W. Summers ◽  
H.A. Wiebe ◽  
K.G. Anlauf
Keyword(s):  
Chemical Composition ◽  
Chemical Structure ◽  
Precipitation Chemistry ◽  
Spatial And Temporal Variability ◽  
Vertical Variation ◽  
Ph Values ◽  
Pollutant Concentrations ◽  
The One ◽  
Physical And Chemical ◽  
Annual Deposition

The physical and chemical structure of the snowpack near North Bay, Ontario was examined during the winter of 1984. precipitation chemistry measurements were also made. A marked areal uniformity was noted in the layered structure of the snowpack and in the vertical variation of the chemical composition. In late January, pH values of the snowpack varied from ∼4.1 at the surface to ∼4.8 near the ground. After rain and a major thaw in February the pH was near 4.8 throughout. Nitrate concentrations exceeded those of sulfate in the snowpack. The molar concentration ratio of / was typically 0.5. Samples of precipitation from six sites had pH values ranging from 3.4 to 5.2. to equivalent ratios were <1 in snow and near 1 or >1 in rain. The chemical composition of the precipitation was closely related to the airmass trajectory. Southerly trajectories yielded the lowest pH values and highest pollutant concentrations. The one-month period from 20 January to 21 February had a deposition of 0.2 g m−2 and a deposition of 0.35 g m−2. For , this deposition would be about one-twelfth the expected annual deposition and for about one-fifth.

Effect of Heat-Setting Temperature on the Hydrazine Treatment of Poly (ethylene Terephthalate) Partially Oriented Yarn

1992 ◽  
Vol 62 (10) ◽  
pp. 575-579 ◽  
Author(s):  
Shouhua Niu ◽  
Tomiji Wakida ◽  
Mitsuo Ueda
Keyword(s):  
Weight Loss ◽  
Nitrogen Content ◽  
Ethylene Terephthalate ◽  
The Other ◽  
Acid Orange 7 ◽  
Acid Dyes ◽  
Heat Setting ◽  
Acid Orange ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Poly (ethylene terephthalate) partially oriented yarn (PET POY) was heat set at 100 to 220°c in a fixed state and then treated with hydrazine. Although crystallinity of the heat-set PET POY increased with increased heat-setting temperature, weight loss from the hydrazine treatment initially decreased at a temperature up to 120°c and subsequently increased above 120°c. The hydrazinolyzed POY fiber is dyeable with acid dyes because of the hydrazide groups incorporated by hydrazinolysis. Nitrogen content and dye exhaustion with CI acid orange 7 showed trends similar to the weight loss of the hydrazinolyzed POY fibers. On the other hand, the dyeability of the hydrazinolyzed POY fibers with CI disperse violet 1 was lower than that of the untreated fibers. Many cracks appeared on the surface of the hydrazinolyzed fibers, and they were smallest on the fibers that were heat set at 120°c.

High Resolution X-Ray Photoelectron Spectroscopy Study of the Interaction of Copper Ion with Chitosan Thin Film

2015 ◽  
Vol 1087 ◽  
pp. 241-245 ◽  
Author(s):  
Wing Fen Yap ◽  
W. Mahmood Mat Yunus ◽  
Zainal Abdib Talib ◽  
Yusof Nor Azah
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Photoelectron Spectroscopy ◽  
Chemical Interaction ◽  
Crosslinking Agent ◽  
Copper Ion ◽  
Aqueous Acetic Acid ◽  
X Ray ◽  
Glass Cover Slip ◽  
Crosslinked Chitosan

In this study, high-resolution X-ray photoelectron spectroscopy (XPS) has been used to study the chemical interaction between copper ion and chitosan thin film. The chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid with glutaraldehyde as crosslinking agent. Then the solution was deposited on glass cover slip by spin coater to form a thin film. The functional group and chemical binding of crosslinked chitosan thin film has been confirmed by XPS. XPS revealed that copper ion adsorbed to the crosslinked chitosan thin film and the functional groups involved in the adsorption mechanisms of copper ion on the thin film were determined.

Novel Amphoteric Cryogels for Cd2+ Ions Removal from Aqueous Solutions

2018 ◽  
Vol 775 ◽  
pp. 376-382 ◽  
Author(s):  
Alzhan Baimenov ◽  
Dmitriy Berillo ◽  
Leila Abylgazina ◽  
Stavros G. Poulopoulos ◽  
Vassilis J. Inglezakis
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Chemical Structure ◽  
Nitrogen Adsorption ◽  
Maximum Adsorption Capacity ◽  
Cadmium Ions ◽  
Texture Analyzer ◽  
Ph Values ◽  
Amphoteric Properties ◽  
Scanning Electron

In this work, amphoteric cryogels based on N,N-dimethyl acrylamide, methacrylic acid and allylamine, crosslinked by N,N-methylenebisacrylamide were synthesized by free-radical polymerization in cryo-conditions. The synthesized cryogels were used for the removal of cadmium ions from aqueous solutions under different pH values. The chemical structure was studied by FTIR, porosity by nitrogen adsorption and morphology by scanning electron microscopy and texture analyzer. The amphoteric properties of cryogels were studied by zeta potential measurements. Adsorption tests revealed that cryogels exhibit 3 times higher adsorption capacity at pH 6.0 than at pH 4.0. The maximum adsorption capacity of the amphoteric cryogels for Cd2+ was 113 mg/g, at pH 6.0 and initial Cd2+ concentration 100 ppm. The results suggest that the predominant removal mechanism is ion exchange between sodium, which initially presents in the structure of the cryogel, and cadmium from the aqueous phase. Recovery studies suggested that the cryogels used can be regenerated and efficiently reused.

Reactions of β-Sulphato-ethylsulphone Crosslinking Agent with Wool

1992 ◽  
Vol 62 (6) ◽  
pp. 309-316 ◽  
Author(s):  
B. M. Smith ◽  
P. L. Spedding ◽  
M. S. Otterburn ◽  
D. M. Lewis
Keyword(s):  
Hplc Analysis ◽  
Crosslinking Agent ◽  
Cross Linking ◽  
Chemical Crosslinking ◽  
The Novel ◽  
Burst Strength ◽  
Ph Values ◽  
Wool Fibers ◽  
Ph Range ◽  
Original Strength

In Part I of our study of the application to wool of the novel chemical crosslinking agent, 2-chloro-4,6-di(-aminobenzene-4-β-sulphato-ethylsulphone)-1,3,5-triazine (XLC), HPLC analysis showed the compound to have good substantivity for wool fibers when applied from boiling aqueous dyebaths in the pH range 3 to 6. In Part II, various solubility and swelling tests have been used to determine whether XLC introduces additional crosslinks into the fiber. The extent of crosslinking depends on the application pH: there is little crosslinking at pH values up to 4, but extensive cross-linking occurs when the compound is applied at pH 5 and 6. Studies on the wet burst strength of XLC treated fabrics indicate that the compound can limit the damage caused to wool by boiling aqueous treatments. For fabrics treated with XLC at pH 6, the compound preserves the original strength of the fabric. Although these results indicate that XLC treatment of wool introduces crosslinks into wool fibers, the mechanism and morphological sites of reaction with wool require further study.

scholarly journals Synthesis and swelling behavior of polyurethane networks based on hyperbranched polymer

2011 ◽  
Vol 65 (6) ◽  
pp. 637-644 ◽  
Author(s):  
Jasna Dzunuzovic ◽  
Marija Pergal ◽  
Slobodan Jovanovic ◽  
Vesna Vodnik
Keyword(s):  
Ethylene Oxide ◽  
Hyperbranched Polymer ◽  
Chemical Structure ◽  
Crosslinking Agent ◽  
Swelling Behavior ◽  
Hydroxyl Groups ◽  
Hyperbranched Polyester ◽  
Polyurethane Networks ◽  
Methylenediphenyl Diisocyanate ◽  
Step Polymerization

A series of six polyurethane (PU) networks was synthesized from BoltornR hydroxy-functional hyperbranched polyester (HBP) of the second pseudo generation as a crosslinking agent, ?,?- dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO) and 4,4?- methylenediphenyl diisocyanate, by a two-step polymerization in solution. Each sample of the prepared PUs had different EO-PDMS-EO content. The chemical structure of the synthesized networks was analyzed by FTIR spectroscopy. The influence of the EO-PDMS-EO content and type of the solvent on the swelling behavior of the PUs in 2-propanol and toluene was investigated. During the swelling measurements certain amount of sol fractions was extracted from the PUs by solvents. According to the 1H NMR results, sol fractions are mainly composed of the soluble hyperbranched PU, formed during the polymerization by partial modification of the end hydroxyl groups of HBP with NCO-terminated prepolymer synthesized in the first step of the reaction. Chains of the so reacted prepolymer can then fold back and form cyclic products by reaction of the free -NCO group from the NCO-terminated prepolymer with free -OH group of HBP. As the EO-PDMS-EO content increases the amount of the sol fractions and swelling degree also increased, indicating that networks with lower EO-PDMS-EO content are more crosslinked and have higher solvent resistance.

Adsorption Kinetics of Zn(II) from Aqueous Solutions onto Epichlorohydrin Crosslinked Chitosan

2012 ◽  
Vol 463-464 ◽  
pp. 7-11 ◽  
Author(s):  
Ming Yan Dang ◽  
Hong Min Guo ◽  
Yan Kun Tan
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Kinetics ◽  
Ph Value ◽  
Crosslinking Agent ◽  
Second Order ◽  
Order Model ◽  
Pseudo Second Order ◽  
Crosslinked Chitosan ◽  
Kinetics Of ◽  
Second Order Model

Chitosan was crosslinked using epichlorohydrin as crosslinking agent to prepare crosslinked chitosan which was used as an adsorbent for the removal of Zn(II) from aqueous solutions. The adsorption prosperities of Zn(II) on crosslinked chitosan were studied, including the influence of pH value and the adsorption kinetics. The kinetics of adsorption was discussed using two kinetic models, the pseudo first-order and the pseudo second-order model. Results reveal that the crosslinked chitosan is suitable as adsorbent to remove Zn(II) from dilute solution. The rate parameters for the Zn(II) by crosslinked chitosan were also determined. It was shown that the adsorption kinetics of Zn(II) could be best described by the pseudo second-order model and the adsorption process may involve a physical adsorption.

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