BACKGROUND Organophosphorus (OP) pesticides are widely used to prevent the destruction of crops by various pests, including insects and rodents, which can affect the yield. On the other hand, the use of OP pesticides is linked to various disorders in animals and humans who are exposed to pesticides directly or indirectly. The current study deals with the use of lanthanum (La)-doped zinc oxide (ZnO) crystals grown on electrospun nanofibers for photocatalytic degradation of methyl parathion (MP), an important OP pesticide. RESULTS The electrospinning process was optimized using various parameters. Similarly, the crystal growth conditions such as La concentration, pH, temperature and time were optimized for further studies. Complete degradation was achieved at 150 min from the start and was supported by a reduction in photoluminescence of the reaction mixture. The total organic carbon content was used to decide the mineralization of the toxin. The degradation followed first-order kinetics with rate constant 0.018 min(-1). Hence MP was successfully degraded using La-ZnO/polyacrylonitrile (PAN) fibers, and the degraded by-product was confirmed by gas chromatography/mass spectrometry (GC/MS) analysis. CONCLUSION Chemically modified La-ZnO/PAN nanofibers were an efficient material to decontaminate the pesticide MP, achieving 100% efficiency. The process may be ecofriendly for upscaling photocatalytic degradation processes. (c) 2019 Society of Chemical Industry