ZnO/Cellulose Nanofiber Composites for Sustainable Sunlight-Driven Dye Degradation

Porous ZnO/cellulose nanofiber (CNF) composites were synthesized to investigate their photocatalytic degradation of methylene blue (MB) dye (a persistent organic pollutant model) under a UV lamp and sunlight. UV/vis analysis indicated that complete photodegradation was achieved in about 10 min under natural sunlight with low UV intensity (between 1500 and 2900 μW/cm–1 of UVA/B). Scanning electron microscopy, Fourier transform infrared, Brunauer–Emmett–Teller, X-ray diffraction, and small-angle X-ray scattering characterization of the composite were consistent with flower/plate morphology ZnO nanomaterials of similar size to the CNF fiber diameter distributed in the matrix. The catalyst with 0.3 M Zn(Ac)2 and 1.5 wt % CNF loading was the sample with the highest MB photodegradation efficiency of >99% in less than 10 min. This study provides proof-of-concept of a simple, sustainable, ecofriendly, and industrially scalable approach to synthesize extremely efficient ZnO/CNF photocatalysts for the degradation of organic pollutants. Catalyst performance showed greater dye degradation with a function of irradiation time as compared to state-of-the-art catalysts reported in the literature.