Construction of hybrid nanocatalyst with enhanced enzymatic and photo-Fenton catalytic activity for the efficient detoxification of profenofos

In recent years, the widespread usage of profenofos in agricultural practices has increased its residues in the environment, posing a serious threat to environmental and human health. However, the degradation efficiency of profenofos through either biotic or abiotic processes alone remains low, and these processes are often accompanied by the generation of secondary pollutants. In this study, a novel hybrid nanocatalyst, OpdB/Fe 3 O 4 @GO@ZIF-8, was synthesized through in situ encapsulation of profenofos hydrolase OpdB and graphene oxide (GO)-wrapped Fe 3 O 4 particles into ZIF-8 crystals via biomimetic mineralization to achieve efficient removal of profenofos. The encapsulated OpdB protected by the ZIF-8 framework exhibited high enzymatic activity in the integrated system. Additionally, the introduction of GO promoted the transfer of photo-generated electrons between ZIF-8 and Fe 3 O 4 , mediating the formation of free radicals during the photo-Fenton reaction. The encapsulated OpdB first specifically catalyzed the hydrolysis of profenofos to produce the main by-product, 4-bromo-2-chlorophenol (BCP), subsequently Fe 3 O 4 @GO@ZIF-8 rapidly degraded BCP through oxidative dehalogenation. The heterojunction exhibited excellent degradation performance for profenofos, implementing the complete detoxification of 50 mg L −1 of profenofos at an irradiation intensity of 300 W and 6 mM H 2 O 2 at pH 5 within 3 h. This performance is superior to any single biodegradation and inorganic catalysis reported previously. The enhanced degradation ability of OpdB/Fe 3 O 4 @GO@ZIF-8 could be attributed to the synergistic effect of the heterojunction formed between the bio-enzymatic and chemical catalysis systems. Overall, this strategy provides novel insights into the construction of heterojunction catalysts based on metal-organic frameworks for the removal and remediation of refractory pesticide pollution in the environment.