Efficient Removal of Tetracycline From Simulated and Real Aquaculture Wastewater Using Solar-Assisted ZnO Photocatalysis

Abstract

Tetracycline hydrochloride (TCT) is a persistent pharmaceutical contaminant frequently detected in aquaculture environments. A preliminary field survey conducted among aquaculture farms identified TCT as the most widely used antibiotic, highlighting the need for effective treatment strategies. This study evaluates advanced oxidation processes-UV light and solar irradiation with ZnO photocatalysis for degrading TCT in both simulated and real aquaculture wastewater. A systematic investigation of operational parameters (pH, irradiation time and intensity, catalyst dosage, oxidant addition, competing anions, and initial TCT concentration) was conducted. The catalyst was characterized using field emission scanning electron microscopy (FESEM) image, transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). The study revealed that a pseudo–first-order kinetic model was followed for TCT degradation at levels up to 90 mg/L. The effect of the presence of multiple contaminants chloroquine (CLQ) and sulphamethoxazole (SMX) on the degradation of target pollutant TCT in water was analyzed. Importantly, complete chemical oxygen demand (COD) removal was achieved even in the presence of co-contaminants CLQ and SMX. LC-QTOF analysis identified intermediate breakdown products, indicating oxidative cleavage and ring-opening reactions. Overall, this work demonstrates that solar-driven ZnO nanoparticle photocatalysis offers a cost-effective, environmentally friendly method for thorough TCT removal in complex wastewater, supporting sustainable water reuse in aquaculture.