Currently, environmental-responsive pesticide delivery systems have become an essential way to improve the effective utilization of pesticides. In this paper, by using hollow mesoporous silica (HMS) as a nanocarrier and TA-Cu metal–phenolic networks as a capping agent, a pH-responsive controlled release nano-formulation loaded with prochloraz (Pro@HMS-TA-Cu) was constructed. The structure and properties of Pro@HMS-TA-Cu were adequately characterised and analysed. The results showed that the loading content of Pro@HMS-TA-Cu nanoparticles was about 17.7% and the Pro@HMS-TA-Cu nanoparticles exhibited significant pH-responsive properties. After a coating of the TA-Cu metal–phenolic network, the contact angle and adhesion work of Pro@HMS-TA-Cu nanoparticles on the surface of oilseed rape leaves after 360 s were 59.6° and 107.2 mJ·m−2, respectively, indicating that the prepared nanoparticles possessed excellent adhesion. In addition, the Pro@HMS-TA-Cu nanoparticles demonstrated better antifungal activity against Sclerotinia sclerotiorum and lower toxicity to zebrafish compared to prochloraz technical. Hence, the pH-responsive nanoparticles prepared with a TA-Cu metal–phenolic network as a capping agent are highly efficient and environmentally friendly, providing a new approach for the development of new pesticide delivery systems.

Residues of pyrethroid pesticides in aquatic environments seriously threaten aquatic organisms and the human health. Herein, a novel highly dispersed and recyclable composite ZIF-8 and SiO 2 double-layer-modified Fe 3 O 4 nanoparticle, named Fe 3 O 4 @ZIF-8@SiO 2 nanoparticle, was synthesized via a layer-by-layer assembly method to remove pyrethroid insecticides (namely, fenvalerate, β-cyfluthrin, and tetramethrin) from water. The physical properties of the Fe 3 O 4 @ZIF-8@SiO 2 nanoparticles were characterized via scanning electron microscopy, elemental mapping, energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma spectroscopy, thermogravimetric analysis, Brunauer−Emmett−Teller surface area analysis, dispersion analysis, and vibrating sample magnetometry. The prepared Fe 3 O 4 @ZIF-8@SiO 2 nanoparticles exhibited excellent adsorption performance and high dispersibility and could be rapidly separated from water using an external magnetic field. The Fe 3 O 4 @ZIF-8@SiO 2 nanoparticles exhibited the strongest adsorption effect at an adsorbent dosage of 10 mg, an adsorption time of 40 min, and a pH of 7. The fitted model for the adsorption process was consistent with the proposed secondary kinetic model and Sips isotherm model. The Fe 3 O 4 @ZIF-8@SiO 2 nanoparticles exhibited maximum adsorption capacities of 316.23, 364.43, and 258.69 mg g −1 for fenvalerate, β-cyfluthrin, and tetramethrin, respectively. The Fe 3 O 4 @ZIF-8@SiO 2 nanoparticles retained most of their adsorption capacity after five reuse cycles when acetone was used as an eluent for desorption. The mechanisms involved in the adsorption process included π−π stacking interactions, hydrogen bonds, hydrophobic interactions, and pore filling effects. This study provides a potential design for rapidly recoverable and reusable nanoparticles that can be used to effectively adsorb pyrethroid insecticides in wastewater.

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Highly efficient and reusable adsorbents for pesticide removal from wastewater have received increasing attention. In this study, Fe 3 O 4 was synthesized using the solvothermal method. Fe 3 O 4 /xSiO 2 and Fe 3 O 4 /xSiO 2 /ySiO 2 were obtained through layer-by-layer silica (SiO 2 ) coating on the surface of Fe 3 O 4 . SiO 2 coating improved the dispersibility of the adsorbent, which can be separated from water rapidly under the action of the external magnetic field. The adsorption capacity of the adsorbent was investigated through removing pyraclostrobin from synthetic wastewater. The adsorbent showed the highest adsorption effect at the adsorbent concentration of 1 mg mL −1 , at a pH of 7, and the adsorbent time of 110 min. The fitting model of the adsorption process conformed to the second-order kinetic model and the Langmuir model. The maximum adsorption capacity of Fe 3 O 4 /xSiO 2 / ySiO 2 nanoparticles was 94.89 mg g −1 , and the removal efficiency was about 96% at adsorption equilibrium. Acetone as the eluent can effectively desorb the adsorbent, and the desorbed adsorbent had high reusability. Particularly, the removal efficiency was still greater than 86% after 9 times of reuse. These results provide a reference for designing reusable nanoparticles to effectively absorb pesticides in wastewater.