Robust and all-inorganic absorbent based on natural clay nanocrystals with tunable surface wettability for separation and selective absorption

We have developed a simple method for fabrication of a robust, three-dimensional all-inorganic porous attapulgite (ATP) monolith based on natural clay nanocrystals using CaCO3 as a hard template. By a simple surface modification with polydimethylsiloxane (PDMS) by the chemical vapour deposition method, the resulting hydrophilic ATP monolith can be tuned to be superhydrophobic and superolephilic for selective absorption of oils or weak polarity organics from water. Also, the surface wettability of the PDMS-treated ATP monolith can be reversibly tailored from superhydrophobic to hydrophilic by simple thermal treatment, making it a multifunctional absorbent for absorption of oils, non-polar or polar organics, and metal ions from water only by simply tuning its surface wettability.