Crop-derived cellulose aerogel with in situ anchored ZIF-8@C for synergistic adsorption and photocatalytic mineralization of dye wastewater

Renewable polysaccharides such as cellulose are abundant and inexpensive yet remain underexplored for conversion into robust multifunctional water-treatment materials. Herein, a cellulose-based composite aerogel was fabricated from deacetylated cellulose acetate (DCA) nanofibers, with sodium alginate (SA) serving as a minor bio-based crosslinker, and ZIF-8@C was anchored in situ on the scaffold via a mineralization-induced interfacial coordination strategy. This strategy suppressed MOF agglomeration and ensured uniform dispersion of active sites, while the Ca 2+ -crosslinked alginate network provided mechanical integrity and hydrophilicity. The aerogel exhibited a maximum methylene blue (MB) adsorption capacity of 617.32 mg/g following the Langmuir isotherm and pseudo-second-order kinetics, governed by electrostatic attraction, π-π stacking, and pore diffusion. Adsorption pre-concentration of MB around the anchored ZIF-8@C sites shortened the diffusion distance of reactive species and accelerated photodegradation, achieving 99% decolorization and 82.3% total organic carbon (TOC) removal within 6 h (apparent rate constant 0.68 h −1 ), confirming deep mineralization rather than simple decolorization. In real water matrices, the aerogel maintained equilibrium uptakes of 89.8–143.2 mg/g, demonstrating robustness against coexisting ions and dissolved organic matter. After five regeneration cycles, 74.34% removal efficiency was retained with Zn 2+ leaching below 0.05 mg/L, indicating environmental safety during repeated use. This work demonstrates a renewable bio-based route that converts naturally abundant polysaccharides into a low-metal-leaching aerogel platform for complete detoxification of cationic dye wastewater, aligned with cleaner production and circular economy principles.