Study of Sorption Kinetics of Doxycycline on pH Sensitive Hydrogel-based Graft Copolymers of Chitosan/Arabinogalactan/ Gummiarabic with Vinyl Monomers

Graft copolymers of natural polysaccharides chitosan (Chs), gummi-arabic (GA) and arabinogalactan (AG) were synthesized with N-vinylpyrrolidone (VPr) (4-vinylpyridine and N-vinylpyrrolidone used as comonomers for chitosan grafting), and then pH-sensitive hydrogels were designing by cross-linked them with N,N-methylene-bis-acrylamide. Effective sorption of doxycycline from aqueous solutions with water-swelling gels has been studied experimentally. The effect of gel dose, initial concentration of doxycycline, pH medium and solution ionic strength of the sorption rate and capacity of the antibiotic was systematically studied. The surface and volume absorption kinetics and isotherms of the process have also been investigated. It was found that the max sorption capacity for swellable gels varies between Chs-graft-VPr/4VPAG/graft-VPrGA/graft-VPr. It has been shown that the sorption mechanism is mainly dominated by physical sorption and to some extent hydrogen bonds and electrostatic interactions.

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PREPARATION OF CHITOSAN GRAFT COPOLYMERS AND STUDY OF THEIR WATER-SWELLING PROPERTIES

IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY ◽

10.35211/1990-5297-2021-12-259-83-90 ◽

2021 ◽

pp. 83-90

Author(s):

A. D. Moroz ◽

S. S. Dryabina ◽

M. A. Vaniev ◽

Zh. N. Malysheva ◽

I. A. Novakov

Keyword(s):

Molecular Weight ◽

Aprotic Solvent ◽

Graft Copolymers ◽

Controlled Radical Polymerization ◽

Methyl Sulfate ◽

Swelling Properties ◽

Degree Of Swelling ◽

Water Swelling ◽

Kinetics Of ◽

Kinetics Of Swelling

In this work, graft copolymers of chitosan with trimethylmethacryloxyethylammonium methyl sulfate were synthesized by the method of controlled radical polymerization, and it was found that replacing the dimethylformamide aprotic solvent with water increases the degree of grafting. With the aim of the possible use of chitosan copolymers as a functional component for regulating the water-swelling properties of elastomers, the kinetics of swelling of the samples was investigated. An increase in the degree of swelling of the copolymers in comparison with the initial chitosan was revealed, and the influence of the molecular weight and the conditions of their synthesis was established.

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Adsorption Properties of Lac Dyes on Wool, Silk, and Nylon

Journal of Chemistry ◽

10.1155/2013/546839 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6

Author(s):

Bo Wei ◽

Qiu-Yuan Chen ◽

Guoqiang Chen ◽

Ren-Cheng Tang ◽

Jun Zhang

Keyword(s):

Electrostatic Interactions ◽

Adsorption Mechanism ◽

Adsorption Properties ◽

Natural Dyes ◽

Affinity Constant ◽

Order Kinetic ◽

Dyeing Process ◽

Order Kinetic Model ◽

Kinetics And Isotherms ◽

Kinetics Of

There has been growing interest in the dyeing of textiles with natural dyes. The research about the adsorption properties of natural dyes can help to understand their adsorption mechanism and to control their dyeing process. This study is concerned with the kinetics and isotherms of adsorption of lac dyes on wool, silk, and nylon fibers. It was found that the adsorption kinetics of lac dyes on the three fibers followed the pseudosecond-order kinetic model, and the adsorption rate of lac dyes was the fastest for silk and the slowest for wool. The activation energies for the adsorption process on wool, silk, and nylon were found to be 107.15, 87.85, and 45.31 kJ/mol, respectively. The adsorption of lac dyes on the three fibers followed the Langmuir mechanism, indicating that the electrostatic interactions between lac dyes and those fibers occurred. The saturation values for lac adsorption on the three fibers decreased in the order of wool > silk > nylon; the Langmuir affinity constant of lac adsorption on nylon was much higher than those on wool and silk.

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In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

10.26434/chemrxiv.9876395.v1 ◽

2019 ◽

Author(s):

Hao Wu ◽

Jeffrey Ting ◽

Siqi Meng ◽

Matthew Tirrell

Keyword(s):

Small Angle ◽

Self Assembly ◽

Electrostatic Interactions ◽

Polyelectrolyte Complex ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Kinetics Of ◽

Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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Modeling of sorption kinetics of U(VI) micro-quantities nanostructured materials with anatase mesoporous structures

Radiochimica Acta ◽

10.1515/ract-2021-1031 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Veniamin Zheleznov ◽

Aleksey Golikov ◽

Tatiana Sokolnitskaya ◽

Sergey Ivannikov

Keyword(s):

Nanostructured Materials ◽

Sorption Kinetics ◽

Uranyl Ion ◽

Competitive Sorption ◽

Hydroxyl Groups ◽

Complex Ions ◽

The Stability ◽

Kinetics Of ◽

Mesoporous Structures ◽

Ionic Forms

Abstract The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.

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Gelatin Beads/Hemp Hurd as pH Sensitive Devices for Delivery of Eugenol as Green Pesticide

Journal of Polymers and the Environment ◽

10.1007/s10924-021-02148-9 ◽

2021 ◽

Author(s):

Gianluca Viscusi ◽

Giuliana Gorrasi

Keyword(s):

Release Kinetics ◽

Barrier Properties ◽

Ph Sensitive ◽

Release Behavior ◽

Sorption Coefficient ◽

Highly Sensitive ◽

Mean Diameter ◽

Ph Conditions ◽

Kinetics Of ◽

Hemp Hurd

AbstractIn this paper gelatin beads reinforced with natural hemp hurd have been produced as pH sensitive devices for the release of eugenol, as green pesticide. The composites beads, with a mean diameter of about 1 mm, were obtained by polymer droplet gelation in sunflower oil. Thermal properties were evaluated showing no noticeable difference after the introduction of hemp hurd. Barrier properties demonstrated an improvement of hydrophobization. The introduction of 5% w/w of hemp hurd led to a reduction of sorption coefficient of about 85% compared to unloaded gelatin beads. Besides, the diffusion coefficient decreased, introducing 5% w/w of hemp hurd, from 8.91 × 10−7 to 0.77 × 10−7 cm2/s. Swelling and dissolution phenomena of gelatin beads were studied as function of pH. The swelling of gelatin beads raised as pH increased up to 2.3 g/g, 9.1 g/g and 27.33 g/g at pH 3, 7 and 12, respectively. The dissolution rate changed from 0.034 at pH 3 to 0.077 h−1 at pH 12. Release kinetics of eugenol at different pH conditions were studied. The released eugenol after 24 h is 98%, 91%, 81 and 63% w/w (pH 3), 87%, 62%, 37 and 32 wt% (pH 7) and 81%, 68%, 60 and 52 wt% (pH 12) for unloaded gelatin beads and gelatin beads with 1%, 3 and 5% of hemp hurd, respectively. The eugenol release behavior was demonstrated to be highly sensitive to the pH release medium, which allows to tune such devices as green pesticide release systems in soils with different level of acidity/basicity.

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