Large-sized graphene oxide/modified tourmaline nanoparticle aerogel with stable honeycomb-like structure for high-efficiency PM2.5 capture

Graphene oxide (GO) aerogel with special porous structure can combine the advantages of its high adsorbability with excellent mechanical properties to show excellent performance in the capture of particulate matter smaller than 2.5 m (PM2.5) and in the recycling of the aerogel. However, the fabrication of the aerogel with durable ordered large through-pores is challenging due to lack of an effective strategy to control the porous structure from the randomly arranged GO sheets. Herein, a facile fabrication strategy towards the stable honeycomb-like-structured GO aerogel, comprising large-sized GO sheets (LGO), via freeze casting with the help of the electrostatic field effect of tourmaline is reported. The added modified tourmaline nanoparticles (mTNPs) effectively reduce the repulsion between GO sheets and highly promote the ordered stacking of LGO sheets to form honeycomb-like-structured aerogel possessing stable large through-pores. Benefiting from its special porous structure, this hybrid aerogel exhibits superior adsorption for PM2.5 and superior recycling performance. When mTNPs loading is 5 wt%, the PM2.5 filtration efficiency of the aerogel is up to 95.1% in the first adsorption cycle, and more importantly, the aerogel can be used repeatedly and retain the high filtration efficiency after simple recycling.