Preparation and adsorption capacity evaluation of graphene oxide-chitosan composite hydrogels

Abstract

(Zhang Q)) ty, and strong mechanical strength [13−16]. For example, Banerjee et al. [17,18] successfully achieved the preparation of various hydrogels that can be used as dye-adsorbing agents in waste-water removal. In addition, this group has also reported metal-nanoparticle-containing GObased hydrogels and novel morphological transformation of graphene based nanohybrids [19−21]. Generally, GObased composite hydrogels were obtained by mixing organic macromolecules or small amphiphiles with an aqueous GO dispersion [22−24]. Chitosan (CS), a well-known compound of chitin N-deacetylation, shows many eco-friendly properties, such as biodegradation, good biocompatibility, and antifungal activity. These characteristics make it a promising candidate in the fields of catalysis, materials, food, drugs, etc. [25−27]. Since GO crosslinks with chitosan via the carboxyl, hydroxyl, epoxy, and amine groups of chitosan, the adsorption capacity of the formed composite is expected to be high. To date, some reports have been published on GO-chitosan nanocomposites used for drug release and antimicrobial activity [28−32].In this study, we report the preparation of GO-based composite hydrogels using the self-assembly of CS and GO, and an in situ reduction approach. The composite hydrogels consist of both hydrogen bonding and electrostatic interactions between the CS molecules and GO sheets. CS molecules were incorporated to facilitate the gelation process of GO sheets, and the dye adsorption capacity of the hydrogel was mainly attributed to the GO sheets. For the three dyes tested in this study, namely, Congo red (CR), methylene blue (MB), and Rhodamine B (RhB), the as-prepared composite hydrogels exhibit good removal rates in accordance with the pseudo-second-order model. More importantly, the hydrogels prepared in this study have potential large-scale applications in organic dye removal and Graphene oxide (GO)-chitosan composite hydrogels were successfully prepared via the self-assembly of chitosan molecules and GO . These as-prepared hydrogels were characterized by different techniques. The morphology of the internal network structure of the nanocomposite hydrogels was investigated. The adsorption capacity results demonstrate that the prepared GObased composite hydrogels can efficiently remove three tested dye molecules, Congo red, methylene blue and Rhodamine B, from wastewater in accordance with the pseudo-second-order model. The dye adsorption capacity of the obtained hydrogels is mainly attributed to the GO sheets, whereas the chitosan molecule was incorporated to facilitate the gelation process of the GO sheets. The present study indicates that the as-prepared composite hydrogels can serve as good adsorbents for wastewater treatment as well as the removal of harmful dyes.

Self-assembled functional components-doped conductive polypyrrole composite hydrogels with enhanced electrochemical performances

“…Due to its large specic surface area and high conductivity, it plays an important role in the morphology and structure of PPy/SA. [10][11][12][13][14][15][16][17] Therefore, in this work, a polypyrrole sodium alginate composite conductive hydrogel was synthesized by in situ polymerization, and was doped with ferric chloride and sodium dodecylbenzene sulfonate. Finally, the morphologies of the three hydrogels were characterized, and the electrochemical performance of the composite conductive hydrogels was tested by cyclic voltammetry and electrochemical impedance spectroscopy.…”

Hierarchical electrospun nanofibers treated by solvent vapor annealing as air filtration mat for high-efficiency PM2.5 capture

“…In the last several years, environmental issues have drawn extensive attention owing to the dangerous nature of their impact on human health and the environment [1][2][3][4]. Particulate matter (PM) is a very complex mixture of pollutants with extremely fine particles and small liquid droplets [5][6][7][8].…”

Preparation of graphene-MoS2 hybrid aerogels as multifunctional sorbents for water remediation

“…Carbon-based three-dimensional (3D) architectures have attracted considerable attention in the past two decades due to their unique properties, such as huge surface area, interconnected porous structures, and macroscopic bulky shape, enabling them to be one of the most promising materials for water treatment [1][2][3][4][5][6]. However, the carbon-based 3D porous networks have limited compatibility and most of them only show affinity to certain category of contaminants [7][8][9][10][11].…”