Construction of β-FeOOH@tunicate cellulose nanocomposite hydrogels and their highly efficient photocatalytic properties.

The environmentally friendly materials fabricated from renewable marine resources have aroused worldwide concerns. Here, for the first time, tunicate cellulose was dissolved in LiOH/urea aqueous solution at -12 °C after ball-milling, and its molecular weight was determined with laser light scattering. Hydrogels were fabricated from the cellulose solution by regenerating in ethanol, and β-FeOOH nanoparticles (NPs) were in-situ synthesized to obtain β-FeOOH/cellulose composite hydrogels (TCH-Fe). The tunicate cellulose hydrogels (TCH) not only disperse uniformly and immobilize firmly the β-FeOOH NPs, but also acted as structural materials for continuous flow photocatalytic system. The photocatalytic degradation of methylene blue (MB) over TCH-Fe achieved up to 99.89% in 30 min under visible-light irradiation, and maintained as high as ∼98% after treatment for 8 h, indicating a highly efficient photodegradation of MB. We provided a low-cost and facile method to construct new sustainable materials derived from marine biomass with highly efficient photocatalytic properties.