Unveiling the Effectiveness of Polystyrene/TiO 2 –Acetylacetone Nanocomposites as Floating Photocatalysts

ABSTRACT Emerging contaminants, a new class of hazardous pollutants, commonly found in wastewater residues, are notoriously difficult to remove/degrade through conventional wastewater treatment processes. Heterogeneous photocatalysis has proven to be a promising alternative for pollutant degradation. However, the use of powder photocatalysts imposes challenges in material recuperation and reusability, while also being prone to causing secondary pollution. Supporting photocatalyst powder on a polymeric matrix, such as polystyrene (PS), may be a practical solution to these drawbacks, especially if the composite exhibits floating capability. The present study aims to prepare PS/TiO 2 –acetylacetone (ACAC) floating nanocomposites through an adapted phase separation approach, and evaluate their photocatalytic activity for the photodegradation of tetracycline (TC) under visible light irradiation and compare them to the powder counterparts. Thermogravimetric analysis proved the immobilization technique to be efficient, and composites' specific surface areas were relatively high, although significantly lower than the powder photocatalysts. While recuperation and reusability were potentially improved, photocatalytic activity suffered a significant reduction due to partial nanoparticle occlusion and poor reaction media coverage. Moreover, total organic carbon (TOC) data revealed that PS‐based composites are susceptible to generating secondary pollution due to the release of microplastics and, possibly, PS photodegradation byproducts, which compromise their viability for environmental remediation purposes.