Sustainable management of atrazine-contaminated water using ZnO-assisted non-thermal plasma: Treatment efficiency, reusability, and phytotoxicity mitigation.

Atrazine (ATZ) is a widely used chlorinated triazine herbicide that poses significant risks to human health and aquatic ecosystems because of its persistence and toxicity. In this study, an efficient plasma-catalytic approach, combining a ZnO catalyst with a direct plasma jet, was developed for degrading ATZ in an aqueous solution. The proposed method was developed specifically to improve the degradation efficiency and mitigate the environmental risk of intermediate by-products. ZnO was synthesized using a coprecipitation method and systematically characterized using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The improved efficiency of the plasma-ZnO system was attributed to enhanced reactive species generation and charge-transfer reactions on the surface of ZnO; these features effectively, promoted ATZ degradation. Optimal degradation was achieved under the following conditions: an ATZ concentration of 10 mg L-1, a solution volume of 50 mL, a ZnO concentration of 0.5 g L-1, and a treatment time of 15 min. Comprehensive plasma diagnostics, including electrical, optical, and physicochemical analyses, were performed to elucidate the plasma characteristics and their role in enhancing the ATZ degradation. Scavenger experiments revealed that hydroxyl radicals (•OH) and ozone (O3) played dominant roles in the degradation mechanism. Furthermore, ZnO exhibited excellent reusability with minimal loss of catalytic activity, showing high stability and excellent practical applicability. Overall, this study demonstrates a strong synergistic effect between ZnO and a plasma jet, confirming that plasma-assisted catalytic strategies are highly effective and promising for the removal of herbicides from water.