Adsorption and photocatalytic degradation of 1,4-dioxane on TiO2

1,4-Dioxane in hexane as a solvent was adsorbed on TiO₂ due to an electrostatic interaction. The porous TiO₂ pellets (SG) prepared by sol–gel method were superior adsorbent to ST-B21 and Degussa P-25. Effects of firing temperature of the pellets and the initial concentrations of 1,4-dioxane on the adsorption percents were examined. Photocatalytic degradation of aqueous 1,4-dioxane gave 1,2-ethanediol diformate and formic acid as intermediates. Analysis of total organic carbon indicated that 1,4-dioxane was mineralized effectively in the following order: P-25 > ST-B21 > SG. The photocatalytic degradation of 1,4-dioxane adsorbed on the TiO₂ pellets in air showed that ST-B21 had a higher activity than SG. These facts indicate that SG pellet acts as a good adsorbent because of its high specific surface area but the internal region of the pores is not illuminated and acts only as a support.