Xanthan Gum Hydrogels as High-Capacity Adsorbents for Dye Removal

Abstract

Xanthan gum-based hydrogels were synthesized and investigated in an attempt to develop efficient adsorbents for removal of dye pollutants from wastewaters. The hydrogels were obtained by first esterifying Xanthan gum with maleic anhydride and subsequent cross-linking of the pendant vinyl groups via thiol-ene click chemistry with oligoethyleneglycol dithiols. The modified hydrogels were systematically characterized to assess the swelling ratio, thermal properties, point of zero charge, and chemical composition. The adsorption capacity (q max) and the corresponding adsorption kinetics and isotherms of the hydrogels were determined using the cationic dye Gentian Violet. The adsorption efficiency was optimized by varying the initial dye concentration, pH, ionic strength, contact time, and adsorbent dosage. The dye removal mechanism was attributed predominantly to electrostatic interactions of the polyanionic hydrogel with the cationic dye and hydrogel swelling. The Langmuir model of monolayer adsorption explained the isotherms very well. At pH 8 to 9, the hydrogel exhibited a high theoretical q max = 502 mg/g (1.23 mmol/g) toward Gentian Violet. The kinetics of adsorption and desorption were best described with pseudo-second-order kinetics and pseudo-first-order model kinetics, respectively. The Xanthan gum-based adsorbent can be regenerated with 0.1 M HCl and reused at least 4 times maintaining over 99% dye removal.

Novel Natural Glycyrrhetinic Acid-Derived Super Metal Gel and Its Highly Selective Dyes Removal

“…For adsorbent materials, reusability is one of the most important properties [ 22 ]. After the contaminants were absorbed by the GA-O-09/Cu 2+ xerogel, the corresponding GA-O-09/Cu 2+ xerogel was filtered from the aqueous solution, and the water was purified.…”

“…Besides, thermodynamic studies [ 22 ] were performed and are shown in Table 3 to study the influence of the temperature on the adsorption process of dye onto GA-O-09/Cu 2+ hydrogel. It could be found that the obtained values of the Gibbs free energy change ΔG 0 were negative and increased with the temperature, which indicated that the adsorption of dye molecules onto the GA-O-09/Cu 2+ hydrogel was spontaneous in nature and became less favorable with an increasing temperature.…”

Mn‐Dependent Morphology and Structure of SnS2 Nanosheets and the Photocatalytic Performance

“…Currently, environmental pollution has brought serious problems threatening human life and health, [1] in which industrial wastewater, such as print and dye, is main pollution source [2] . For example, methyl violet (MV) and rhodamine B are widely used in textile, pharmaceutical, and biological dyes [3,4] and they are recognized as a carcinogenic and mutagenic agent to living organisms [5,6] . Thus, it is necessary to remove methyl violet from wastewater by simple and high‐efficient route such as photocatalytic technology [7] .…”

“…[2] For example, methyl violet (MV) and rhodamine B are widely used in textile, pharmaceutical, and biological dyes [3,4] and they are recognized as a carcinogenic and mutagenic agent to living organisms. [5,6] Thus, it is necessary to remove methyl violet from wastewater by simple and high-efficient route such as photocatalytic technology. [7] To achieve this goal, high-performance photocatalysts are required to promote removal of pollutants from wastewater.…”

Equilibrium, kinetic, and thermodynamic studies of new materials based on xanthan gum and cobalt ferrite for dye adsorption

“…The high number of carboxyl and hydroxyl functional groups on the surface of xanthan gum allows its functionalization with the aid of modification approaches, for example, chemical treatment of bio-composite systems. [19,20] Njuguna et al [21] grafted dithiols to xanthan gum and used it as an adsorbent for Gentian Violet. Liu et al [22] used xanthan gumgraphene oxide hybrid aerogels to remove Methyl Blue (MB) and Rhodamine B from wastewater.…”