Oxybenzone (BP-3) and 2-(5-tert-butyl-2-hydroxyphenyl) benzotriazole (BTZ) serve as UV absorbers, with the former effectively shielding skin from harmful UVA and UVB rays in sunscreens and personal care products, and the latter protecting oils and synthetic materials from yellowing and degradation due to UV exposure. Bisphenol A, a prevalent bisphenol, is commonly used in creating polycarbonate plastics and epoxy resins, contributing to widespread environmental and human exposure. Both bisphenols and UV absorbers pose significant environmental pollution concerns and health risks, with their presence confirmed in surface and wastewater, food, beverages, and biological samples like urine, serum, and blood. In our master's thesis, we explored the adsorption of selected bisphenols and UV absorbers on two iron oxide nanoparticle variants developed at the Jožef Stefan Institute. We devised an analytical method employing liquid chromatography-mass spectrometry (LC-MS) to detect bisphenols and another using liquid chromatography with a UV-VIS detector (LC-UV-VIS) for UV absorbers. Our research focused on how pH levels and the compound-to-nanoparticle ratio affect adsorption rates. Initial experiments with bisphenols were curtailed due to mass spectrometer issues, redirecting our attention to UV absorbers. We discovered that environmental pH significantly influences the absorption of BP-3 onto nanoparticles, with higher adsorption rates at higher pH levels, indicating more efficient binding in acidic conditions. Conversely, pH had negligible impact on BTZ adsorption, as almost the entire amount of the compound is bound under both conditions. The quantity of nanoparticles added did not significantly affect compound binding, although lower concentrations of compounds in the sample led to lower relative adsorption of the compounds onto the nanoparticles. Over time, compound concentrations slightly diminished even without nanoparticles, suggesting potential compound instability or non-adsorptive losses, possibly through precipitation or adhesion to container walls. To answer these questions a set of new experiments would need to be done however this was beyond the scope of this master’s thesis. Nevertheless, our findings suggest successful adsorption of UV absorbers by the nanoparticles, with BTZ adsorbing almost completely (⡈ 99%) in acidic and basic conditions, BP-3 adsorbing 40% in acidic and 25% in basic.
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