A Transparent, High-Strength, and Recyclable Core–Shell Structured Wood Hydrogel Integrated with Carbon Dots for Photodegradation of Rhodamine B
Junyao Li, Yu Wang, Yiying Yue
Abstract
The opacity, fragility, and environmental unfriendliness of the traditional photocatalytic matrix cannot fully utilize the properties of photocatalysts and efficiently degrade pollutants. In this work, a transparent wood hydrogel with a core–shell structure was developed using transparent wood (TW) impregnated with polyacrylic acid (PAA) as the core layer and Bi-N-carbon dots/BiOBr (Bi-N-CDs/BiOBr) photocatalyst-initiated polymerization of acrylic acid (AA) monomers as the shell layer. In the shell layer, nanoscale CDs with rich hydrophilic groups built a link between BiOBr and PAA and strengthened the adsorption–photocatalysis synergistic removal for RhB. The original wood backbone well conserved during preparation led to an anisotropic structure in the resultant Bi-N-CDs/BiOBr@TW photocatalytic wood hydrogel. Namely, after introducing Bi-N-CDs/BiOBr as the linker and reinforcing agent, the tensile strength was up to 3.2 and 11.03 MPa along the radial (R-) and axial (A-) directions, which was 1.6- and 1.06-fold of R-TW and A-TW, respectively. Hence, Bi-N-CDs/BiOBr@TW with high strength furnishes multiple separations and reutilizations, and the RhB removal rate is approximately 85% after five cycles. The Bi-N-CDs/BiOBr@TW exhibited light transmittance up to 64.6 and 52.3% at 800 nm along the R- and A-directions, respectively. Moreover, the adsorption–photocatalysis synergistic rate of Bi-N-CDs/BiOBr@TW reached 93% in 300 min at pH = 7. This paper offers a strategy for fabricating wood hydrogels with outstanding stretchability, transparency, dye removal efficiency, and recyclability, opening a significant route for alleviating dye pollution.