Synthesis, Characterization and Sorption Capacity Examination for a Novel Hydrogel Composite Based on Gellan Gum and Graphene Oxide (GG/GO)

Abstract

A novel hydrogel composite based on gellan gum and graphene oxide (GG/GO) was synthesized, characterized and tested for sorption capacity in this work. The microstructural, thermogravimetric and spectroscopic analysis confirmed the formation of the GG/GO composite. Comparative batch sorption experiments revealed a sorption capacity of the GG/GO composite for Zn (II) ions of approximately 2.3 higher than that of pure GG. The GG/GO composite exhibits a maximum sorption capacity of 272.57 mg/g at a pH of Zn (II) initial solution of 6. Generally, the sorption capacity of the sorbents is approximately 1.5 higher in slightly acidic conditions (pH 6) comparative with that for strong acidic conditions (pH 3). The sorption isotherms revealed that the sorption followed a monolayer/homogenous behavior. The sorption kinetic data were well fitted by the pseudo-second-order kinetic model, and were consistent with those derived from sorption isotherms. The intraparticle diffusion was considered to be the rate-determining step. Two main sorption mechanisms for Zn (II) were identified namely, ion exchange at low pH values, and both ion exchange and chemisorption in weekly acidic conditions.

Graphene Oxide‐Doped Gellan Gum–PEGDA Bilayered Hydrogel Mimicking the Mechanical and Lubrication Properties of Articular Cartilage

“…Our data confirmed that the hydrogels did not affect this important parameter. Only three papers focused on different combinations of GG/PEGDA [ 35,67 ] and GG/GO, [ 68 ] but cell viability was evaluated only in GG/PEGDA hydrogels. In line with our data, they have demonstrated that mesenchymal stromal cells embedded in GG/PEGDA showed a high percentage (above 87%) of viable cells.…”

Sorption Behavior of Grafted Porous Microparticles Based on Methacrylic Monomers and Chitosan/Gellan Gum towards Copper(II) and Nickel(II) Ions in Aqueous Solutions

“…The increase of pH from 1 up to 7 led to the improvement of their sorption capacity due to the decrease of the protonation degree of the amine groups, and thus the number of binding sites available for the sorption of Copper(II) and Nickel(II) ions increased significantly. The carboxylate groups of the GG 1 and GG 3 microparticles are non‐ionized at pH values less than 3.4 and become ionized at pH values higher than 4.4 [40] . Thus, with increasing of the pH values, the carboxylate groups belonging to the grafted GLL cause the swelling of GG 1 and GG 3 microparticles, leading to the expansion of the polymer chain facilitating the penetration of metal ions to the binding sites.…”

Crosslinked Carboxymethyl Sago Starch/Citric Acid Hydrogel for Sorption of Pb2+, Cu2+, Ni2+ and Zn2+ from Aqueous Solution

“…Developing countries like Malaysia have been exposed to heavy metal pollution that comes from different sources, like agriculture, industrial and domestic activities, which predominantly contribute to a high concentration of heavy metal ions discharge through sewage and straight into water source [ 1 , 2 , 3 ]. Accumulation of these hazardous inorganic pollutants could eventually enter the food chains and cause a detrimental effect on living organisms and human health with high toxicity and carcinogenicity [ 4 ].…”

“…Conversely, the sorbent can be derived from a low-cost material, such as agricultural waste, natural material, modified biopolymer and industrial by-product [ 9 , 10 ]. As a result, there are rising numbers of studies on the sorption of heavy metal by polysaccharides-based hydrogel owing to their accessibility, economical, renewability, biodegradability and environmental compatibility to practice green chemistry [ 3 , 11 , 12 ].…”

“…The term ‘network’ in hydrogels points out crosslinks that must exist in order to prevent the dissolution of polymeric chains [ 13 ]. However, previous studies have shown various type of polysaccharides-based hydrogel that has been used as a heavy metal sorbent, for example, gellan gum [ 3 ], potato starch [ 14 , 15 ], gum tragacanth [ 9 ] and cellulose [ 16 ]. The key feature to facilitate high sorption capacity is the presence of hydrophilic functional groups, like amine, hydroxyl, carboxylic acid or sulfonic acid acting as chelating agent for removal of heavy metal ions from aqueous solution [ 17 ].…”