Robust three-dimensional g-C3N4@cellulose aerogel enhanced by cross-linked polyester fibers for simultaneous removal of hexavalent chromium and antibiotics

Current environmental concerns have encouraged researchers to search for a facile, environmentally-friendly and efficient method for sewage treatment. Cellulose aerogels (CAs) with high porosities, large specific surfaces and sustainability are promising candidates as catalytic carriers to solve many environment problems. However, pure CAs often lack mechanical strength and are prone to collapse under a small force, especially in water. Here, blended polyester fibers (B-PET) were used to support a CA containing nanosheet graphitic carbon nitride (g-C3N4), which greatly enhanced the tensile strength of the pure CA. Moreover, the composited aerogel, g-C3N4@CA/B-PET, showed high impact resistance in the water impact experiment and maintained its robust structure after 24 h of water shock. The g-C3N4@CA/B-PET exhibited a favorable photocatalytic activity towards the removal of hexavalent chromium and antibiotics simultaneously, which could challenge freestanding g-C3N4. The as-prepared composite material could be reused easily and maintained its excellent photocatalytic performance in cycling tests. Finally, the possible pathway for the degradation of sulfaquinoxaline and the mechanism in this photocatalytic system were proposed, where the superoxide radicals (O2−) were the dominant active species, resulting in the oxidation of antibiotics. In addition, the photoelectrons could reduce the toxic hexavalent chromium to harmless trivalent chromium.