Freeze Granulation of Nanoporous UiO-66 Nanoparticles for Capture of Volatile Organic Compounds

Nanoporous UiO-66 spherical beads prepared by using PVA binder successfully connected UiO-66 nanoparticles together into granular beads with improved mechanical strength for toluene capture. This was achieved without affecting the crystalline nature and micropore structures of the material. The regular octahedron of the UiO-66 individual nanoparticle remained intact, and the micropore size did not change with increasing PVA addition without which the nanoporous UiO-66 could not granulate into beads. However, PVA bound the nanoparticles together to form compact and cohesive network clusters that reduced the BET surface area and total pore volume. This consequently lowered the toluene adsorption efficacy slightly due to the premature breakthrough that limited the toluene molecular exposure into the micropores of the individual UiO-66 nanoparticles.