Development of Blended Biopolymer-Based Photocatalytic Hydrogel Beads for Adsorption and Photodegradation of Dyes

Abstract

Blended biopolymer-based photocatalytic hydrogel beads were synthesized by dissolving the biopolymers in 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]), adding TiO2, and reconstituting the beads with ethanol. The incorporation of modifying biopolymer significantly enhanced the adsorption capacity of the cellulose/TiO2 beads. Cellulose/carrageenan/TiO2 beads exhibited a 7.0-fold increase in adsorption capacity for methylene blue (MB). In contrast, cellulose/chitosan/TiO2 beads showed a 4.8-fold increase in adsorption capacity for methyl orange (MO) compared with cellulose/TiO2 beads. In addition, cellulose/TiO2 microbeads were prepared through the sol–gel transition of the [Emim][Ac]-in-oil emulsion to enhance photodegradation activity. These microbeads displayed a 4.6-fold higher adsorption capacity and 2.8-fold higher photodegradation activity for MB than the millimeter-sized beads. Furthermore, they exhibited superior dye removal efficiencies for various dyes such as Congo red, MO, MB, crystal violet, and rhodamine B, surpassing the performance of larger beads. To expand the industrial applicability of the microbeads, biopolymer/TiO2 magnetic microbeads were developed by incorporating Fe2O3. These magnetic microbeads outperformed millimeter-sized beads regarding the efficiency and time required for MB removal from aqueous solutions. Furthermore, the physicochemical properties of magnetic microbeads can be easily controlled by adjusting the type of biopolymer modifier, the TiO2 and magnetic particle content, and the ratio of each component based on the target molecule. Therefore, biopolymer-based photocatalytic magnetic microbeads have great potential not only in environmental fields but also in biomedical fields.

pH-Responsive Cellulose/Silk/Fe3O4 Hydrogel Microbeads Designed for Biomedical Applications

“…Our group previously prepared various blended cellulose/biopolymer hydrogel microbeads, including cellulose/lignin/Fe 3 O 4 , cellulose/chitosan/Fe 3 O 4 , cellulose/starch/Fe 3 O 4 , and cellulose/carrageenan/Fe 3 O 4 , for dye and protein adsorption [ 14 ]. We also prepared photocatalytic hydrogel microbeads, such as cellulose/carrageenan/TiO 2 and cellulose/chitosan/TiO 2 , through a sol–gel transition using [Emim][Ac] [ 20 ].…”

Electrosprayed Stearic-Acid-Coated Ethylcellulose Microparticles for an Improved Sustained Release of Anticancer Drug

“…In general, soluble cellulose derivatives can be exploited for promoting the fast release of the poorly water-soluble drugs, such as a series of hydroxypropyl methylcellulose [ 28 ]. Insoluble cellulose derivatives are often exploited for drug extended- or sustained-release profiles, such as ethylcellulose (EC) and cellulose acetate (CA) [ 29 , 30 ]. These cellulose derivatives have fine film-forming, filament-forming, and other processing properties [ 31 ].…”