Removal of hazardous volatile organic compounds from water by vacuum pervaporation with hydrophobic ceramic membranes

• TiO2 and Al2O3 ceramic membranes are successfully modified by perfluoroalkylsilanes.
• Hydrophobic membranes are applied to pervaporative removal of MTBE, EtAc and BuOH.
• Selectivity of membranes depends on the density of the hydrophobic surface layer.
• Hansen׳s solubility parameters are applied to discuss pervaporation results.

Hydrophobic alumina and titania micro and mesoporous ceramic membranes were prepared by grafting of C6F13C2H4Si(OEt)3 (C6) molecules and subsequently applied in a pervaporation (PV) process to the removal of hazardous organic solvents (MTBE, EtAc and BuOH) from binary aqueous solutions. The transport and separation properties of investigated membranes were discussed. Additionally it was found that membrane material and grafting time have an important impact of the pervaporative properties. All tested membranes were selective toward organics. Titania membrane was the most efficient and was characterized by the highest value of PSI and the highest value of permeate flux of organic compounds in water–EtAc (JEtAc=1.1 kg h−1 m−2; PSIEtAc=140 kg h−1 m−2) and water–MTBE (JMTBE=1.0 kg h−1 m−2; PSIMTBE=194 kg h−1 m−2) systems. This behavior of titania membrane was also discussed based on the Hansen solubility parameters. In presented work the evaluation of MTBE removal degree with titania modified membrane from water binary mixture in the pervaporation process was discussed.

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