Abstract
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•ZnO/quartz was used as a catalyst and adsorbent for the removal of ibuprofen (IBF).•It exhibits receptor sites and adsorption capacity of 38.42 mg/g and 145.6 mg/g.•The adsorption reactions of IBF by ZnO/quartz is of physisorption mechanisms.•50 mg/L of IBF was oxidized after 80 min (Photocatalyst) and 40 min (Piezo-photocatalyst).•The hydroxyl and superoxide radicals are the main oxidizing species.
A natural piezoelectric quartz core was coated with environmentally friendly ZnO nanoparticles (GZn/PQz) for enhanced decontamination of ibuprofen (IBF) by adsorption and advanced oxidation. The adsorption properties were described based on the monolayer model of one energy site. The steric studies demonstrated a decline in active site density (Nm) and the saturation adsorption capacities (Qsat) with increasing temperature, and the best values were achieved at 25 °C (Nm = 38.42 mg/g and Qsat = 145.6 mg/g). The number of adsorbed IBF molecules (n) (>3 and <4) suggested the uptake of 3 or 4 IBF molecules per receptor site in a vertical orientation and by a multimolecular mechanism. The adsorption energy values (−7.93 to −9.5 kJ/mol) suggest physical uptake processes. The thermodynamic functions reflected the exothermic and spontaneous properties of the reactions. GZn/PQz achieved IBF (50 mg/L) oxidation percentages of 100%, 93.8%, and 100% after 80 min (photocatalyst), 360 min (piezoelectric catalyst), and 40 min (piezo-photocatalyst), respectively. Hydroxyl radicals and superoxide radicals are essential oxidizing species during the oxidation of IBF by GZn/PQz. Based on the detected intermediate compounds, the oxidation pathway of IBF by GZn/PQz involved hydroxylation, decarboxylation/demethylation, and ring-opening processes.