Presentation Title

Heterogeneous Ozonolysis and UV Photolysis of Chlorpyrifos Thin Films

Faculty Mentor

Jessica W. Lu

Start Date

23-11-2019 8:00 AM

End Date

23-11-2019 8:45 AM

Location

219

Session

poster 1

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

We have explored the degradation of chlorpyrifos, an organophosphate pesticide, by studying heterogeneous ozonolysis and UV photolysis of chlorpyrifos thin films via attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Chlorpyrifos is an acetylcholinesterase inhibitor that causes developmental neurotoxicity that is widely used in U.S. agriculture, but banned from residential use. While work examining chlorpyrifos degradation in solution and in the gas phase are well-represented in literature, there are few investigations of chlorpyrifos decomposition on surfaces. Our studies into the degradation of chlorpyrifos are performed by controlled exposure of thin films of chlorpyrifos to ozone and UV light (254 nm, 302 nm, 365 nm) in a custom stainless steel reaction chamber and tracking the surface-bound reaction products, in order to identify surface reaction products, determine reaction rate constants, and elucidate reaction mechanistic pathways. Preliminary results show that chlorpyrifos is readily converted to chlorpyrifos oxon in the presence of both ozone and UV light, likely due to the production of reactive oxygen species. However, degradation appears limited when chlorpyrifos is exposed only to either ozone or UV light. Ultimately, these ongoing experiments will help provide new information about the reaction products, mechanisms and kinetics for the surface reactions of chlorpyrifos under environmentally relevant conditions.

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Nov 23rd, 8:00 AM Nov 23rd, 8:45 AM

Heterogeneous Ozonolysis and UV Photolysis of Chlorpyrifos Thin Films

219

We have explored the degradation of chlorpyrifos, an organophosphate pesticide, by studying heterogeneous ozonolysis and UV photolysis of chlorpyrifos thin films via attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Chlorpyrifos is an acetylcholinesterase inhibitor that causes developmental neurotoxicity that is widely used in U.S. agriculture, but banned from residential use. While work examining chlorpyrifos degradation in solution and in the gas phase are well-represented in literature, there are few investigations of chlorpyrifos decomposition on surfaces. Our studies into the degradation of chlorpyrifos are performed by controlled exposure of thin films of chlorpyrifos to ozone and UV light (254 nm, 302 nm, 365 nm) in a custom stainless steel reaction chamber and tracking the surface-bound reaction products, in order to identify surface reaction products, determine reaction rate constants, and elucidate reaction mechanistic pathways. Preliminary results show that chlorpyrifos is readily converted to chlorpyrifos oxon in the presence of both ozone and UV light, likely due to the production of reactive oxygen species. However, degradation appears limited when chlorpyrifos is exposed only to either ozone or UV light. Ultimately, these ongoing experiments will help provide new information about the reaction products, mechanisms and kinetics for the surface reactions of chlorpyrifos under environmentally relevant conditions.