Abstract
In this study, redispersible copper oxide nanoparticles (CuO NPs) with an average size of 92.18 nm were synthesized using ethylene glycol as a complexing agent and sodium poly(4-styrenesulfonic acid-co-maleic acid) as a stabilizer. The CuO NP dispersion remained stable for 30 days. In the CuO NPs/methylene blue (MB) system, the MB absorption peak at 664 nm weakened or disappeared, while a new peak at 583 nm emerged, indicating the formation of a charge-interaction complex confirmed by zeta potential measurements. Under UV irradiation, CuO NPs showed weak photocatalytic activity, degrading MB by 8.7%, 8.8%, and 9.7% at dosages of 1.3, 1.9, and 2.5 mM, respectively. At 0.6 mM CuO NPs, flocculation occurred, and FT-IR analysis confirmed MB adsorption onto CuO NPs with a capacity of 217.4 mg g(-1), indicating that MB was mainly separated from the system through adsorption by CuO NPs rather than being degraded via photocatalysis. With hydrogen peroxide, CuO NPs achieved nearly complete photodegradation (99.6%) of 53.5 μM MB within 75 minutes. This work offers novel insights into the development of redispersible nanomaterials and their applications in water treatment.