title: Highly porous ZIF-8 nanocrystals prepared by a surfactant mediated method in aqueous solution with enhanced adsorption kinetics.
abstract: ZIF-8 nanocrystals with a sub-100 nm size are prepared by a surfactant mediated method in aqueous solution. Pure ZIF-8 phase can be obtained with a stoichiometric Zn/2-methylimidazole ratio. The surfactant mixture of Span 80 and Tween 80 may stabilize the Zn/2-methylimidazole coordination structure and prevent the formation of the hydroxide or alkaline salt. The nanocrystals maintain a high specific surface area of 1360 m(2)/g. The particle size effect on the adsorption kinetics of the ZIF-8 nanocrystals is studied by using two different probing molecules (I3(-) anion and Rhodamine B molecule). For the I3(-) anion, which is smaller than the aperture size of ZIF-8, the ZIF-8 nanoparticles exhibit faster absorption kinetics compared to the bulk material. For the Rhodamine B molecule, which is larger than the aperture size of ZIF-8, only surface adsorption occurs. The enhanced adsorption kinetics of the ZIF-8 nanoparticles is attributed to the smaller particles size, which reduces the intraparticle diffusion length. ZIF-8 nanocrystals prepared by a surfactant mediated method in aqueous solution exhibit faster adsorption kinetics compared to the bulk material.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), (The State Key Laboratory of Rare Earth Materials Chemistry and Applications), College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Fan
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Junwen
authors.initials: J
authors.lastname: Zhou
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Xingguo
authors.initials: X
authors.lastname: Li
keywords: ZIF-8; aqueous solution; kinetics; nanocrystal; surfactant