Fate and behaviour of the UV filter 3-methylbutyl-(2E)-3-(4-methoxyphenyl)-acrylate (IMC) in aqueous solution

The disinfection-induced and photo-induced degradation of the UV filter 3-methylbutyl-(2E)-3-(4-methoxyphenyl)-acrylate (IMC) is investigated. High performance liquid chromatography was used to follow the degradation reactions, determine kinetic features and also the influence of external variables on degradation [pH; temperature; chlorine concentration; dissolved organic matter (DOM) concentration]. Liquid chromatography preceded by solid-phase extraction, was used for the determination of by-products. IMC was found to rapidly and substantially degrade in aqueous solution, when in exposure to active chlorine, displaying a pseudo second-order degradation rate constant of 0.042 ± 0.001 L mol−1 s−1, and a half-life period of 23.8 ± 0.6 s. Contact with aqueous active chlorine proved to yield merely the dichlorinated form of IMC, as the prominent disinfection by-product. The assessment of influence of external variables on degradation, was insured by a Box-Behnken experimental design formulation approach, with factorial analysis. In this regard, data shows that temperature plays a decisive factor in the reaction rate, without DOM in solution, leading to decreasing degradation rates as the temperature increases. With DOM in solution, pH and DOM proved to be the most influential variables on IMC degradation. Regarding the photo-degradation study, results have shown that IMC remained quite stable in aqueous solution when exposed to artificial solar radiation, with a rate constant of 0.00073 ± 0.00002 min−1 and a half-life period of 938.5 ± 31.1 min. This work addresses yet another filter that has never been studied, and hopes to provide clarification on its environmental fate and behaviour when in the aqueous environmental compartments.