Synthesis of BiVO4/g-C3N4 S-scheme heterojunction via a rapid and green microwave route for efficient removal of glyphosate

In this work, a green reaction route for the preparation of BiVO4/g-C3N4 composite is constructed using the acetic acid and reusable ethylene glycol system combined with the microwave method. The rice grain-like BiVO4 is successfully deposited on the surface of hollow tubular g-C3N4 to form a S-scheme heterojunction within 25 min. The performance of the prepared photocatalysts is evaluated by removing glyphosate, methyl orange and tetracycline hydrochloride from simulated agricultural and urban runoff. The degradation evaluation results show that acetic acid in this route could play a better induction role compared to the conventional inducer nitric acid, while the ethylene glycol in this route can be recycled. The recovery of ethylene glycol could reach more than 85%, and the performance of the produced photocatalyst will not be decreased after the recovery of ethylene glycol reaches 20 times. The BV/CN60-R20 sample has the highest photocatalytic activity for glyphosate removal under simulated sunlight irradiation, which is 14.5 times and 9.7 times higher than that of pure BiVO4 and g-C3N4, respectively. In summary, the establishment of the ethylene glycol and acetic acid system not only provides a new perspective for the replacement of strong acids in the preparation of BiVO4-based photocatalyst but also provides a reference for the construction of other harmless and recyclable systems.