Photoadsorption and photocatalytic processes affecting the composition of the Earth's atmosphere: II. Dark and photostimulated adsorption of Freon 22(CHF2Cl) on MgO

The interaction of hydrogen-containing Freon 22 (CHF2Cl) with the surface o f MgO that was held in air both before and after heating at 620 K in the da rk or under exposure to soft UV radiation, which corresponded to the solar spectrum in the troposphere, is examined. Up to 1% of a Freon 22 monolayer is adsorbed on the surface of MgO in the dark, and more than 10% of a monol ayer was adsorbed under UV irradiation. The photoadsorption activity is not associated with the presence of nitrogen-containing compounds formed by th e adsorption of nitrogen oxides from air on the surface of MgO. Magnesium o xide does not adsorb hydrogen-free Freon 12 (CF2Cl2) either in the dark or under exposure to UV radiation.