Adsorption of crude oil from crude oil–water emulsion by mesoporous hafnium oxide ceramics

We report a mesoporous hafnium oxide (MHO) ceramic synthesized via a sol–gel process that has exhibited 99.9% removal capacity of crude oil from an oil-in-water emulsion at a concentration of 3 mg mL⁻¹. The as-prepared MHO ceramic was regenerated after crude oil sequestration via calcination at 800 °C under ambient conditions. The scalability of the synthetic method and thermal stability of the MHO ceramic material makes it a promising, underexplored, and reusable adsorbent for efficient oil spill clean-up.