Enhanced photocatalytic degradation of 2,4-dichlorophenoxyacetic acid from freshwater and industrial wastewater using TiO2–CuO–clay soil nanocomposites

2,4-Dichlorophenoxyacetic acid (2,4-D) is a synthetic herbicide used to control weeds and enhance agricultural productivity. However, it is toxic and carcinogenic, posing significant risks to environmental pollution and human health. This study investigates the effectiveness of TiO₂-CuO-clay soil nanocomposites in the photocatalytic degradation of pesticides from Ziway Lake and industrial wastewater. The two sets of composites were synthesized with different concentrations of TiO₂-CuO-clay soil: the first with a ratio of 2:3:7 (TiO₂, CuO and clay soil), and the second with a ratio of 4:3:5 (TiO₂, CuO and clay soil). The mixture was treated with microwave digestion at 150 °C for 10 min, followed by filtration and calcination at 720 °C for 6 h in a muffle furnace. The morphology and the particle size of the nanocomposites were characterized using XRD, SEM, FTIR and BET techniques. The pesticide degradation from Ziway Lake and pesticide factory effluents was carried out using a UV-vis spectroscopy lamp with a wavelength of 280 nm, with samples retained for 2, 5, 7, and 9 h. The removal efficiency of 2,4 D was then analyzed by HPLC. The results revealed that the degradation efficiency of TiO₂-CuO-clay soil composite was 96.18% and 99.84% for surface water and pesticide factory effluent, respectively. The removal efficiency increased with longer contact duration, higher light intensity, and greater composite concentrations. The study demonstrates that TiO₂-CuO-clay soil composites were an effective technology for pesticide degradation in surface water and industrial wastewater.