Photocatalytic and photochemical decomposition of N2O on ZnS-MMT Catalyst

Abstract

ZnS nanoparticles stabilized by cetyltrimethylammonium bromide were deposited on montmorillonite forming the ZnS-MMT nanocomposite. The nanocomposite was characterized by UV–vis DRS, SEM-EDAX, FTIR, XRD and nitrogen physisorption and tested for N2O photocatalytic decomposition in an annular batch reactor illuminated with an 8 W Hg lamp (254 nm wavelength). Photolysis of N2O was tested at the same conditions.

The N2O conversion in inert gas was 79% after 24 h of illumination and was attributed to the simultaneous N2O photocatalytic and photochemical decomposition. The presence of water vapor inhibited photocatalytic reaction pathway while N2O photolysis was improved. Photocatalytic performance was higher with catalyst in fluidized bed than in fixed bed. The reason is that both mass and photon transfer to the photocatalyst was maximized. Better results were obtained with Zn-MMT compared to Evonic P25 catalyst.