Green ZnO photocatalysts for emerging pollutant removal: Powder vs. coating approaches

Advanced oxidation processes, particularly heterogeneous photocatalysis, have gained attention
as promising technologies for the degradation of persistent organic micropollutants that are
resistant to conventional water treatment methods. The aim of this study was to evaluate the
efficiency of eco-inspired ZnO photocatalysts, prepared from green tea (GTE) – and banana peel
extracts (BPE), in both powder and coating forms, for the removal of emerging pollutants (pesticide
tembotrione – TEM and synthetic hormone 17α-ethinylestradiol – EE2) from water, under various
experimental conditions (catalyst loading, initial pH, water matrix) using simulated solar irradiation.
High-performance liquid chromatography with diode array and fluorescence detectors was
employed to monitor the degradation kinetics of the target compounds. Additionally, the newly
prepared materials were characterized using advanced techniques (e.g. XRD, SEM). The results
demonstrated significant photocatalytic activity of the new ZnO materials, with degradation
efficiencies reaching 96% for TEM (ZnO GTE) and 83% for EE2 (ZnO BPE), after 60 min of
irradiation.