Bifunctional Fe@CNT Composite for Solar-Driven Purification of Organic Sewage

Water scarcity and pollution are the challenges most countries face around the world, especially the large amount of organic wastewater. Solar-driven evaporation is an environmentally friendly and high-performance technology of freshwater production. However, photothermal materials fail when the water includes complex recalcitrant pollutants such as tetracycline hydrochloride (HCL-TC) and bisphenol A (BPA). Here, Fe@carbon nanotube (Fe@CNT) arrays were prepared in situ by using acetonitrile as the carbon source and ferrocene as the catalyst, followed by further solar-driven water evaporation and photo-Fenton catalytic degradation of organic pollutants synergistically. Owing to the Fenton effect and excellent solar absorption, Fe@CNTs accelerate the separation of photogeneration electron–hole pairs to improve the degradation of organic pollution and production of freshwater. Therefore, the Fe@CNT layers show outstanding solar absorption and hydrophilicity, resulting in a high solar evaporation efficiency of 94%. Meanwhile, the degradation efficiencies of organic pollutants (methylene blue, HCL-TC, and BPA) are more than 99% due to the synergistic effect of photothermal and photo-Fenton-catalysis effects. This work provides a promising strategy for the treatment of organic wastewater in an environmentally friendly way.