Microwave-assisted photocatalytic degradation of dimethyl phthalate using a microwave discharged electrodeless lamp

Abstract

The microwave-assisted photocatalytic degradation (MW/PC) of dimethyl phthalate (DMP) was investigated, using a microwave discharged electrodeless lamp (MDEL) as the UV source. DMP could be rapidly and completely degraded by the MW/PC process. The effects of photocatalyst dosage, UV light intensity, initial pH and concentration of DMP, as well as irradiation time, were studied in detail. Synergistic effects were found to exist between microwave irradiation and TiO2 photocatalysis, and the greater efficiency of the MW/PC process might be ascribed to non-thermal effects of microwave irradiation. Detection results confirmed that microwave irradiation could give rise to the generation of hydroxyl radicals. The major intermediates of DMP in the MW/PC process were deduced to be phthalic acid monomethyl ester, phthalic acid, o-phenyl diethyl ketone and o-phthalic anhydride. Based on the results, two initial degradation pathways of DMP were proposed.