4-Methylbenzylidene camphor (4-MBC) is commonly used in sunscreens and cosmetics to protect human skin from ultraviolet irradiation. This work investigated 4-MBC degradation via sunlight/free chlorine process, by focusing on the degradation kinetics, participation of different reactive species (e.g., OH radical, O3, Cl radical and other reactive chlorine species), transformation byproducts generation and toxicity change. Sunlight simulator (Suntest CPS; Atlas, Chicago, IL, USA) was utilized for conducting photolysis experiments and the irradiation intensity was set at 700 W/m2. The concentration of 4-MBC was analyzed by Sciex API 4000 LC−MS/MS (Applied Biosystems, Foster City, CA, USA) and the transformation byproducts were identified by using Triple TOF™ 5600 (AB SCIEX, CA, USA). Several parameters which affect sunlight/free chlorine process were studied, including free chlorine dosage, solution pH and the presence of common water constituents (HCO3−, Cl−, dissolved organic matter). By studying the rate constants between 4-MBC with different reactive species, the contribution of each reactive species on 4-MBC degradation were understood. The change in toxicity during 4-MBC degradation in sunlight/free chlorine process was measured by Microtox®. We also performed the sunlight/free chlorine process in swimming pool water matrix to understand 4-MBC degradation and transformation in real conditions.

Degradation of 4-methylbenzylidene camphor by sunlight photolysis in the presence of free chlorine

2019 Spring National Meeting

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