Construction of MgFe2O4/rGO/WO3 Z-scheme photocatalyst for efficient degradation of organic pollutants: performance, mechanism, and reusability

MgFe 2 O 4 /rGO/WO 3 (MAG) Z -scheme visible light-driven photocatalyst was successfully synthesized with high purity. Synergic effects within MAG Z -scheme photocatalyst effectively enhanced the photocatalytic activity by a factor of 1.5–3.3. The photocatalytic performance was evaluated through the degradation of tetracycline (TC), ciprofloxacin (CIP) antibiotics, methylene blue (MB), direct blue 71 (DB-71), livestock and textile industrial wastewaters. MB and DB-71 degradation efficiency catalyzed by MAG reached 90.22 ± 2.56 % and 87.62 ± 2.26 % after 150 min, while these figures for TC and CIP were respectively 84.47 ± 2.16 % and 78.58 ± 2.36 %. The removal efficiency depended on contact time, pH value, catalyst dosage, pollutant concentration, and co-existing ions. Radical trapping tests and electron paramagnetic resonance spectroscopy analyses showed that superoxide anion radicals were mainly responsible for degrading the pollutants. The chemical oxygen demand and toxicology assessment revealed about 75 % of organic dyes and 67 % of antibiotics were mineralized while the toxicology of the by-products was negligible. The photocatalytic performance was high and stable after five repetitive cycles, with no discernible changes to the photocatalyst's surface properties. COD removal efficiency for textile and livestock wastewaters respectively reached 48.6 % and 42.9 %, lower than those for synthetic samples due to the presence of other organic compounds and co-existing ions, but met national technical regulations on the effluents of livestock and textile industry of Vietnam. The findings in this work provide a practical approach to mitigating hazardous organic dyes and antibiotics commonly found in textile and livestock wastewaters, thereby protecting public health and the environment.