Degradation of trichloroethylene using highly adsorptive allophane–TiO2 nanocomposite

A highly adsorptive allophane–TiO2 nanocomposite photocatalyst was prepared by dispersing nanoparticles of the natural clay mineral allophane into a titanium alkoxide solution by the sol–gel method. During the photocatalytic degradation of trichloroethylene using the allophane–TiO2 nanocomposite, emission of the intermediate product, phosgene, was drastically inhibited. Trichloroethylene was transformed into the intermediate products, phosgene and dichloroacetyl chloride, on the TiO2 during the UV irradiation. These compounds are rapidly adsorbed on the allophane. The compounds then gradually degraded after diffusing to the TiO2.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ A highly adsorptive allophane–TiO2 nanocomposite was prepared by the sol–gel method. ▶ Phosgene emission was drastically inhibited during the trichloroethylene degradation. ▶ Trichloroethylene was transformed into phosgene on the TiO2 during UV irradiation. ▶ The phosgene was rapidly adsorbed on the allophane. ▶ The phosgene then gradually degraded after diffusing to the TiO2.