Complexes of Polydopamine-Modified Clay and Ferric Ions as the Framework for Pollutant-Absorbing Supramolecular Hydrogels

Abstract

Clay-based functional hydrogels were facilely prepared via a bioinspired approach. Montmorillonite (clay) was exfoliated into single layers in water and then coated with a thin layer of polydopamine (PDOPA) via in situ polymerization of dopamine under basic aqueous conditions. When a small amount of ferric salt was added into aqueous suspensions of the polydopamine-coated clay (D-clay), D-clay and Fe(3+) ions could rapidly self-assemble into three-dimensional networks through the formation of coordination bonds. Consequently, supramolecular hydrogels were formed at very low D-clay contents. Rheological measurements show that the D-clay/Fe(3+) hydrogels exhibit fairly elastic response in low stain range, and have self-healing capability upon removal of applied large stress. More importantly, the hydrogels can be used as adsorbents to effectively remove Rhodamine 6G (Rh6G), an organic pollutant, from water. UV-vis absorption spectra of the Rh6G-loaded hydrogels show bands related to π-π stacking interactions between the aromatic moieties of PDOPA and Rh6G, confirming the formation of PDOPA/Rh6G complex on the surface of D-clay.

Injectable dopamine‐modified poly(α,β‐aspartic acid) nanocomposite hydrogel as bioadhesive drug delivery system

“…In previously reported work, the dopamine modified polymer formed hydrogel after the addition of Fe 3+ , which was attributed to the coordination effect between catechol ligands and Fe 3+ . Moreover, besides the coordination effect, the oxidation reaction was observed in a catechol‐chitosan hydrogel induced by Fe 3+ under acidic pH conditions .…”

Highly regenerable alkali-resistant magnetic nanoparticles inspired by mussels for rapid selective dye removal offer high-efficiency environmental remediation

“…[4][5][6] Among these methods, adsorption is a promising method because of its effectiveness, relatively low cost and easy operation. 29 Despite their considerable adsorption capabilities, most previously reported PDA-based adsorbents are limited by poor alkali resistance, lack of selective adsorption capacity and unsatisfactory recyclability. [7][8][9][10][11] Recently, inspired by the unique wet adhesion capability of marine mussels, polydopamine (PDA) has attracted strong interest as a biomimetic material and surface modification agent for various applications.…”

An effective heterogeneous iron-based catalyst to activate peroxymonosulfate for organic contaminants removal

“…Various supports, such as clay [21], resin [22], zeolite [23], and activated carbon [24], have been used to prepare heterogeneous iron-based catalysts. Compared with these supports, activated carbon fibers (ACFs) represent a highly microporous carbon material with an extremely high adsorption capacity and a large surface area.…”