Highly efficient Ag@β-FeOOH/cellulose nanofibril composite hydrogel for rapid photocatalytic degradation of tetracycline under visible light

Improving the dispersibility and recoverability of powdered catalysts is essential for developing efficient and cost-effective photocatalytic systems. Herein, silver-loaded β -FeOOH/quaternized cellulose nanofibrils composite hydrogel, denoted as Ag@ β -FeOOH/QCNF, was successfully prepared via an in-situ synthesis approach combined with photodeposition for environmental remediation. The composite hydrogel consisted of a three‑dimensional porous network, with β -FeOOH photocatalysts and Ag nanoparticles uniformly distributed. The composite hydrogel not only exhibited adsorption capacity toward organic pollutant but also established multidimensional electron‑transport pathways that facilitated the migration of photo-generated charge carrier, thereby significantly enhancing light-harvesting efficiency. The synergistic effect between adsorption and photocatalysis enabled hydrogel to achieve nearly complete degradation of tetracycline (100%) within 30  min under simulated visible light, while maintaining a removal efficiency above 94% over five consecutive cycles, demonstrating outstanding stability and reusability. Free radical scavenging experiments demonstrated that ·OH and h + were the primary reactive species responsible for pollutant degradation. Overall, this study presents a straightforward approach to construct 3D network-structured hydrogel materials with efficient photocatalytic performance, which holds significant potential for applications in water purification.