Removal of high concentration dimethyl methylphosphonate in the gas phase by repeated-batch reactions using TiO2

The aim of our study is to develop apparatuses that use TiO 2 for effective decontamination of air contaminated by Sarin gas. We performed photocatalytic decomposition of gaseous dimethyl methylphosphonate (DMMP) by TiO 2 and identified the oxidization products. The high activity of TiO 2 (0.01 g) was observed under UV-light irradiation and high concentration DMMP (33.5 μM) was removed rapidly. On the other hand, DMMP was not decreased under UV-light irradiation without TiO 2 . This indicates that photocatalytic treatment is very effective for the removal of DMMP. Methanol, formaldehyde, formic acid, methyl formate, CO, CO 2 and H 2 O were detected as the primary products. In the gas phase, no highly poisonous substances were detected. In order to examine the performance of photocatalytic activity during long-term reactions, we performed photocatalytic decomposition by repeated-batch reactions using TiO 2 . High photocatalytic activities decreased gradually. Meanwhile, the strong adsorption of TiO 2 against DMMP was observed as photocatalytic activities decreased. During the repeated-batch reactions with the sample scaled up (TiO 2 : 0.1 g), the total amount of removed DMMP reached 968.5 μM by both photocatalytic decomposition and the strong adsorption of TiO 2 . These results suggest the possibility of removing large amounts of DMMP.