Institut Charles Sadron Event

This thesis investigates a novel strategy to eliminate low-concentration antibiotic residues from wastewater, addressing a major driver of global antimicrobial resistance that conventional wastewater treatment plants fail to solve. To achieve complete pollutant degradation without external chemical additions, this work develops a self-sustaining, immobilised photocatalytic system targeting the antibiotic (sulfamethoxazole). The mechanism relies on the synergism between two complementary photocatalysts: phosphorus-doped graphitic carbon nitride (PGCN), which uses visible light to produce hydrogen peroxide (H2O2) in situ via two-electron oxygen reduction, and titanium dioxide P25 (TiO2 P25), which immediately consumes the generated H2O2 through a photo-Fenton-like reaction to generate highly reactive hydroxyl radicals (HO.). To eliminate the need for post-treatment filtration, layer-by-layer (LbL) electrostatic self-assembly is employed to immobilise the catalysts at room temperature. After optimizing the assembly parameters on model flat silicon wafers, the dual-catalyst multilayers were successfully transposed onto 3D open-cell polyurethane and silicon carbide-alumina foam supports. By combining the high surface area, low pressure drop, and light penetration of 3D foams with a self-sustaining radical generation mechanism, this work demonstrates an effective, scalable platform for advanced water treatment. Keywords: Photocatalysis, Layer-by-Layer assembly, hydrogen peroxide, phosphor modified g-C3N4, TiO2 P25, open-cell foams, antibiotic degradation, water treatment.