O-Modified Activated Carbon Fiber Electrode Efficiently Adsorption of Cu (II) in Wastewater

At present, wastewater discharged from many industries contains a large amount of Cu (II). In this study, an O-modified activated carbon fiber (O-ACF) with high adsorption activity was prepared by oxidation modification of activated carbon fiber with 20% nitric acid. O-ACF was used to adsorb Cu (II) in water. Electrode adsorption experiments showed that O-ACF had excellent electro-adsorption performance for Cu (II), and the maximum adsorption capacity was 48.60 mg/g, which was 1.63 times that of commercial activated carbon. After optimizing and adjusting the voltage (0.6–1.2 V), pH (2–10) and electrode plate spacing (5–20 mm), it was found that the most favorable working conditions for electro-adsorption of Cu (II) by O-ACF electrode were voltage of 1.0 V, solution pH of about 6, and electrode plate spacing of 10 mm. The kinetic model fitting showed that the adsorption effect of O-ACF on Cu (II) was mainly chemical adsorption. The intraparticle diffusion model further found that the adsorption of Cu (II) by O-ACF was influenced by membrane diffusion and internal diffusion. Adsorption regeneration experiment showed that O-ACF still maintained 95% adsorption performance for Cu (II) after 5 times of adsorption regeneration, which had good practicability. This study provides an excellent material for capacitive deionization system, which is expected to be applied in sewage treatment, seawater desalination and nutrient recovery.