Facile synthesis of PVDF photocatalytic membrane based on NCQDs/BiOBr/TiO2 heterojunction for effective removal of tetracycline

Highlights: • The NCQDs/BiOBr/TiO₂/PVDF photocatalytic membrane was successfully fabricated. • 0.5-NCQDs-BiOBr-TiO₂/PVDF membranes exhibited high photocatalytic performance. • Synergistic effect between NCQDs and heterojunction improved photodegradation. • A possible mechanism of the enhanced photocatalytic efficiency was proposed. Porous TiO₂ nanorods were synthesized by H₂SO₄ etching method, combined with the synthesis technology of BiOBr-TiO₂ heterojunction and NCQDs to synthesis the ternary NCQDs-BiOBr-TiO₂ photocatalyst. The micromorphology and structural composition of different powder catalysts and photocatalytic composite membranes were studied by means of various characterization methods. The UV–vis DRS results indicated that the formation of BiOBr-TiO₂ heterojunction and the introduction of NCQDs extended the visible light absorption range of photocatalytic materials. The BSA adsorption performances of different composite membranes were investigated, and the results showed that 0.5-NCQDs-BiOBr-TiO₂/PVDF composite membranes had strong antifouling properties. Moreover, it was found that the 0.5-NCQDs-BiOBr-TiO₂/PVDF composite membranes exhibited high regeneration stability and easy separation recovery performance. The results showed that the TC degradation rate of 0.5-NCQDs-BiOBr-TiO₂/PVDF composite membranes reached 77% within 120 min. Moreover, the pseudo first order kinetic apparent rate constant k value of the 0.5-NCQDs-BiOBr-TiO₂/PVDF composite membranes was 0.01342 min⁻¹.