Fabrication of 2D/1D Bi₂WO₆/halloysite nanotubes photocatalyst towards water purification: a support effect on in situ construction and electron–hole separation

Abstract

Water pollution caused by antibiotics has seriously harmed human health. Photocatalytic oxidation has been widely studied for the treatment of organic pollutants in water due to its sustainability, high efficiency, and no secondary pollution. However, the nano-photocatalyst is easy to agglomerate in water, which greatly limits the efficiency of pollutant degradation. To improve the activity of photocatalysts and attain desirable solar energy conversion, the mineral-supported photocatalysts have gained considerable attention in practical applications. Herein, a reusable and efficient 2D/1D heterogeneous structure photocatalyst based on amine-functionalized halloysite nanotubes (MHNTs) and Bi2WO6 nanosheet (BWO) was prepared using a facile hydrothermal method for decomposing antibiotics under simulated sunlight. The effects of composite catalysts with different preparation conditions on the degradation of tetracycline hydrochloride (TCH) were discussed. The results showed that over BWO/MHNTs with a mass ratio was 3:1, the synthesizing temperature was 120°C and the precursor pH value was 1, the TCH (10 mg/L) degradation efficiency reached 100% after 1 h irradiation of simulated sunlight. Moreover, BWO/MHNTs composites kept good recovery and stable photocatalytic activity after 5 cycles. The high activity and stability of the composite catalyst could be attributed to the good dispersion of Bi2WO6 on the surface of clay minerals and the facilitated electron-hole separation. In addition, the radical capture test revealed that the ·O- 2 played the most important role in the photodegradation of TCH. Thus, BWO/MHNTs composites exhibit a good application prospect in the field of natural light photocatalytic degradation towards antibiotics pollutants in water.