Amphoteric gellan gum-based terpolymer–montmorillonite composite: synthesis, swelling, and dye adsorption studies

Abstract

A terpolymer gel, Gellan gum-graft-poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-dimethylaminopropyl methacrylamide) and its composite with the clay, Montmorillonite, was prepared by free-radical polymerization and crosslinking reactions in solution. The terpolymer gel and the clay composite were characterized using FTIR, TGA, SEM, and X-ray diffraction techniques. Swelling studies were carried out in different pH and salt solutions. The gel showed maximum swelling capacity in alkaline medium, while the composite showed higher swelling in neutral medium. The swelling of the gel and the composite followed second kinetics model and water transport is found to be a less Fickian diffusion process. The terpolymer gel and the composite were evaluated for the adsorption of rhodamine B (RhB) and chromotrope 2R (C2R) dyes. Rhodamine B is found to be adsorbed to a higher extent than chromotrope 2R and the adsorption isotherm studies suggested that adsorption of both RhB and C2R on the terpolymer gel was best explained by Langmuir model, while the adsorption on the Composite fitted best into Freundlich model. Similarly, the adsorption kinetics data for both RhB and C2R dyes followed the second-order kinetics.

Facile fabrication and structural elucidation of lignin based macromolecular green composites for multifunctional applications

“…The modification of peak of pectin in composite LPG at 3399 cm −1 confirmed the possibility of interaction of carboxylic ─OH group either with lignin or with gellan. Similarly, the glucopyranose of gellan, having peak at 3427 cm −1 is also involved in interaction either with pectin or lignin in the composite LPG 46,47 . The possible chemical interaction of polymeric composite LPG is illustrated in Figure 5.…”

“…The Ho “pseudo‐second‐order kinetic model” is based on the assumption that adsorption at the surface involves chemisorption, where the physicochemical interaction at the interphase is reasonable for removal of solute from the solution. Integrating the Equation (), and when time t = 0, q t = 0, then the equation will be where k 2 is the pseudo‐second‐order reaction rate constant (g mg −1 h −1 ) and all other parameters have their usual meaning. The q e and k 2 are derived from the obtained slope and Y‐intercept of the t/q t versus time graph 42,43,47 …”

Intelligent sustained‐release microgel for reduced permeability of fluid channels: Synthesis and properties

“…With the increase in the ionic degree of the monomer, the adsorption ratio gradually increased and then decreased, and it reached the peak value when the ionic degree of the monomer was 10%. This was due to the ''anti‐polyelectrolyte'' property of amphoteric ion on the macromolecular chain of the microspheres and the effect of the salt 33,34 . The amphoteric ions promoted the adsorption of Na 2 SiO 3.…”

“…This was due to the ''anti-polyelectrolyte'' property of amphoteric ion on the macromolecular chain of the microspheres and the effect of the salt. 33,34 The amphoteric ions promoted the adsorption of Na 2 SiO 3. 35 In amphoteric hydrogels, the addition of sodium silicate electrolyte would disturb the intermolecular electrostatic attraction of the anions and cations, leading to the destruction of physical cross-linking network and…”

Porous microparticles based on methacrylic copolymers and gellan as drug delivery systems

“…The second‐order kinetic model was applied to describe the swelling mechanism. The values of the second‐order swelling rate constant ( k s ) was calculated from the following equation: …”