3D, eco-friendly metal-organic frameworks@carbon nanotube aerogels composite materials for removal of pesticides in water

Highlights: • Novel 3D MOFs modified carbon nanotube/chitosan composite aerogels were prepared. • The composite aerogels with hierarchical structures are flexible and lightweight. • The composite aerogels exhibit excellent adsorption capacity of pesticides and reusability. • The risk of secondary pollution of MOFs was reduced by growing MOFs onto carbon nanotube. To alleviate the secondary risks of using metal-organic frameworks (MOFs) nanoparticles as adsorbent, a novel method of loading two MOFs (ZIF-8 or UiO66-NH₂) on the carbon nanotube aerogels (MPCA) by in situ nucleation and growth of MOFs nanoparticles onto carbon nanotubes were developed. The prepared MOFs@MPCA aerogels were well characterized via SEM, TEM, EDS, FT-IR, XRD and XPS to reveal the microstructure and formation mechanism of MOF@MPCA Besides, the hydrophilia, mechanical property and thermostability of MOF@MPCA were investigated. The results showed that MOF@MPCA had good hydrophilia, compression resilience and thermostability. The study on the ability to adsorb herbicides (chipton and alachlor) showed that the adsorption capacity of MOF@MPCA was stronger compared with single MOFs nanoparticles, which indicated that there was a synergistic effect between MOFs and MPCA. The equilibrium adsorption capacity of chipton adsorbed by UiO66-NH₂@MPCA was 227.3 mg/g, and can be expediently reused for 5 cycles without a significant decrease in adsorption performance. Moreover, the results of biosafety experiments showed that MPCA can reduce the risk of MOFs nanoparticles leakage into the environment and accumulation in organisms. This work can provide a new research idea, which has potential applications to remove pollutants effectively and safely from the environment.