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.
Pristine graphene oxide (GO) sheets were pretreated with polyethyleneimine (PEI) to prepare PEI-modified GO (PEI-GO), which was further inserted with ZIF-8 crystals to form a novel PEI-GO@ZIF-8 nanocomposite for CO 2 capture. The good dispersion of PEI and interlayer growth of ZIF-8 within the GO sheets is helpful for high CO 2 adsorption. Therefore, the PEI-GO@ZIF-8 nanocomposite show high surface area and enhanced CO 2 adsorption capacity . The adsorption capacity of the PEI-GO@ZIF-8 nanocomposite was six times higher than that of the pristine GO and ZIF-8. The CO 2 /N 2 adsorption selectivity was significantly improved due to amine groups loading which provide more sites for CO 2 adsorption. The preferential adsorption of CO 2 over N 2 makes PEI-GO@ZIF-8 nanocomposite be a promising candidate in the field of CO 2 capture.
Bio-nanocomposites have attracted increasing research attention because they are able to integrate bio- and nano-related functions, and subsequently demonstrate potentially beneficial environmental applications. Here, a functional bionanomaterial based on Burkholderia cepacian (FZ) immobilized on GO/ZIF-8 was developed and used to remove malachite green (MG), with functions based on both biodegradation and adsorption. XRD and FTIR results showed that in situ production of GO/ZIF-8 by combining Zn 2+ in ZIF-8 with the carboxyl group on the GO surface, led to FZ immobilized in GO/ZIF-8 through covalent bonding. Zeta analysis showed that the surface of FZ and GO/ZIF-8 had different charges under pH = 9.12, suggesting immobilization also occurred via electrostatic action. BET results confirmed that the specific surface area of GO/ZIF-8 was much larger than that of GO and ZIF-8, but the reduced specific surface area of FZ@GO/ZIF-8 could be due to FZ loading on its surface. The efficiency of FZ@GO/ZIF-8 in the removal of MG reached 99% and furthermore retained good stability after five cycles. The efficiency in removing multiple ions in river water reached more than 80%, which is evidence strongly suggesting that FZ@GO/ZIF-8 is an environmental bionanomaterial with effective application potential.
危险品化学品经营许可证（带存储）