Structure engineering of Fe-based MOF aerogel by Halloysite Nanotubes for efficient methylene blue adsorption

Halloysite Nanotubes (HNTs) with large surface/volume ratio and rich reactive groups are incorporated into Fe-based MOF aerogel to develop MOF(Fe)/HNTs composite aerogels for efficient methylene blue (MB) adsorption. A sol–gel method along with supercritical drying technology is applied for the preparation of the MOF(Fe)/HNTs composite aerogels. Micro-morphology and pore structure of the aerogels are properly regulated by controlling the addition amount of HNTs. The obtained samples show three-dimensional mesoporous network structures. The addition of HNTs can slightly increase the specific surface area of the aerogel and then decrease gradually with the increase of HNTs content. The MOF(Fe)/HNTs composite aerogels show favorable adsorption property towards MB and the maximum adsorption capacity can be 384 mg/g with the adsorption efficiency of 96.1%. Besides, the adsorption kinetic analysis reveals that the adsorption process of the MOF(Fe)/HNTs composite aerogel follows the pseudo-second-order model, indicating that chemical sorption may be the rate-limiting step.