Stable TiO2–USY zeolite composite coatings for efficient adsorptive and photocatalytic elimination of geosmin from water

Abstract

Geosmin is an unpleasant tasting germacranoid sesquiterpene to which human taste buds are sensitive even at the parts per trillion (ppt) level. The elimination of this molecule from water is a great scientific challenge due to the extremely low concentration needing to be removed. In this paper, we report simple fabrication of stable titania (TiO₂) and Y zeolite composite coatings via a layer-by-layer dip-coating approach for efficient adsorptive and photocatalytic elimination of geosmin up to 99% from 100 ppt geosmin aqueous solution within 120 minutes at 35 °C under UV light. Zeolite coatings are also found to be highly efficient for adsorptive elimination of geosmin at a minute concentration of 4 ppt, the typical concentration level found in aquaculture water. Geosmin concentrations in the ppt range were determined by the headspace solid phase microextraction (HS-SPME) technique in combination with gas chromatography-mass spectrometry (GC-MS). This study demonstrates the potential of a composite coating comprising zeolite Y for concentrating, and TiO₂ photocatalyst for eliminating geosmin in drinking water production and aquaculture water purification.