Byproduct Analysis from Gamma Radiolysis of 1,2,4-Trichlorobenzene in Benzene

Abstract

In this study, we investigated the degradation properties of trichlorobenzene (TCB) as a model compound for hexachlorobenzene (HCB), utilizing benzene as the solvent, with the purpose of understanding the efficiency and pathways of gamma radiolysis in the remediation of persistent organic pollutants (POPs). Gamma radiation from a ⁶⁰Co source was employed, and mainly qualitative changes in the sample solutions were analyzed using gas chromatography-mass spectrometry (GC-MS). Our findings demonstrate a 99,1% conversion of TCB, resulting in the formation of various less chlorinated benzenes (CBs) and other chlorinated and non-chlorinated organic compounds. Specifically, 39 distinct compounds were identified in the TCB + benzene system based on their mass spectra. By-products such as, 3,5-dichlorobiphenyl, 4,4'-dichloro-1,1'-biphenyl, and 3,4-dichloro-1,1'-biphenyl (PCBs) exhibit significant carcinogenic hazards. These findings underscore the potential health risks associated with the radiolytic degradation process of POPs in benzene. The G value for TCB degradation in benzene exhibits 5,47 molecules/100 eV at an absorbed dose of 3,0 kGy. However, the G value subsequently declines to 0,19 molecules/100 eV with higher doses, a trend that reflects not only the saturation of the reactive species' capacity but also the diminishing concentration of TCB, limiting further degradation despite increased radiation exposure.