ZnO photocatalyst for degradation of toxic pollutants and for treatment of pig manure as a promising strategy for house fly (Musca domestica L.) control

The preparation of zinc oxide (ZnO) photocatalyst by a facile chemical precipitation route was reported. The thin plate-like ZnO photocatalyst exhibited the hexagonal phase with the energy band gap of 3.04 eV. Under UV light irradiation, the prepared ZnO photocatalyst showed 94% and 90% removal of reactive red 141 (RR141) azo dye and oxytetracycline (OTC) antibiotic, respectively. Interestingly, the enhanced photocatalytic performance of 97% and 93% toward degradation RR141 and OTC, respectively, was obtained under natural sunlight irradiation. The removal of the pollutants agrees well with the first-order kinetic model showing the rate constant of 0.043 min−1. This demonstrates the promising role of the synthesized ZnO photocatalyst for environmental protection. Furthermore, the prepared ZnO was also used for the treatment of pig manure as a novel strategy for house fly control. The treatment of pig manure with ZnO had little effect in a choice test but strongly inhibited oviposition in a no-choice test, significantly lowering the number of eggs laid. Although the treatment did not affect survival rates or development times, it imposed significant sublethal fitness costs: larvae reared on treated manure were significantly smaller, and the resulting adult population had a lower female-to-male ratio. These effects were linked to a suboptimal protein-to-carbohydrate ratio in the treated manure. Chemical analysis confirmed that the treatment altered the manure's volatile profile, reducing key attractants like butanoic acid and ammonia. The treatment of pig manure with the prepared ZnO constrains house fly populations through a dual mechanism: inhibiting oviposition and reducing the fitness of subsequent generations. This approach represents a promising and sustainable tool for integrated pest management in livestock environments.