Highly efficient indoor air purification using adsorption-enhanced-photocatalysis-based microporous TiO_2 at short residence time

摘要

A short residence time is a key design parameter for the removal of organic pollutants in catalyst-based indoor air purification systems. In this study, we synthesized a series of TiO_2 with different micropore volumes and studied their removal efficiency of indoor carbonyl pollutants at a short residence time. Our results indicated that the superior adsorption capability of TiO_2 with micropores improved its performance in the photocatalytic degradation of cyclohexanone, while the photocatalytic removal of the pollutant successfully kept porous TiO_2 from becoming saturated. When treated with 1 mg m~(-3) cyclohexanone at a relatively humidity of 18%, the adsorption amount on microporous TiO_2 was 5.4-7.9 times higher than that on P25. Removal efficiency via photocatalysis followed the same order as the adsorption amount: TiO_2-5 > TiO_2-20 > TiO_2-60 > TiO_2-180 > P25. The advantage of microporous TiO_2 over P25 became more pronounced when the residence time declined from 0.072 to 0.036 s. Moreover, as the concentration of cyclohexanone deceased from 1000ppb to 500 ppb, removal efficiency by microporous TiO_2 increased more rapidly than P25.