Directional charge transfer driven by superior interfacial electric field in AT-PDI/BOB toward simultaneous removal of tetracycline and Cr(VI).

In order to solve the problem of compound pollution of antibiotics and heavy metals in water, AT-PDI/Bi4O5Br2 (AT-PDI/BOB) composites with strong interfacial electric field (IEF) were prepared by hydrothermal method. In the coexistence system containing Tetracycline (TC) and Cr(VI), the material shows obvious synergistic degradation effect, with a degradation rate of 88.9% for TC and 98.2% for Cr(VI). The 10-h flow experiment validated its stability, maintaining the degradation rates of TC and Cr(VI) at approximately 73% and 86%. The enhanced IEF largely illustrates a significant performance improvement because it successfully drives the directional separation and migration of light-induced carriers. Free radical extinction experiments show that the main active substances involved in degradation are •O2-, h+, and e-. TC effectively consumes h+ and •O2- in the system, thereby facilitating e- extraction and accelerating the degradation of Cr(VI). The present study provides new ideas for the design of high-performance photocatalysts that utilize the IEF to treat water pollution containing both antibiotics and heavy metals.