Preparation and immobilization of Bi2WO6/BiOI/g-C3N4 nanoparticles for the photocatalytic degradation of tetracycline and municipal waste transfer station leachate

Bi2WO6/BiOI nanoparticles were embedded into graphitic carbon nitride (g-C3N4) to fabricate a new visible-light-driven photocatalyst (Bi2WO6/BiOI/g-C3N4). Furthermore, the immobilization of Bi2WO6/BiOI/g-C3N4 was performed by a new method characterized by using polytetrafluoroethylene (PTFE) as an adhesive agent and boric acid (H3BO3) as a pore-forming agent. Bi2WO6/BiOI/g-C3N4 possesses the higher photocatalytic performance than Bi2WO6/BiOI and g-C3N4 for tetracycline degradation because of the enhancement of light absorption and electron/hole (e(-)/h(+)) pairs separation. After immobilization, Bi2WO6/BiOI/g-C3N4 still remained considerable activity and stability. For the degradation of tetracycline, the immobilized photocatalyst presented the degradation rate of over 90 % within 120 min, whereas the photocatalytic degradation of municipal waste transfer station (MWTS) leachate for 28 h presented the chemical oxygen demand (COD) removal rate of 56.1 % and the total organic carbon (TOC) removal rate of 50.4 %. Additionally, the biodegradability of the two test solutions was enhanced evidently after the photocatalytic degradation. This work mainly provides a new photocatalyst immobilization method to promote the large-scale application of photocatalytic degradation.