Photodegradation of humic acid using spherical activated carbon contained Zn in a fluidized bed system

Abstract

In this study, a strong acid ion-exchange resin, as the starting material of spherical activated carbon contained Zn (Zn-SPAC), was treated by 0.1 N zinc solution. Ion-exchange treatment was performed from one to three times for controlling the zinc content. The ion-exchanged resins were activated under N2/H2O vapor atmosphere at 900°C for 0.5 h, followed by carbonization treatment at 700°C under N2 atmosphere. The Zn-SPAC samples were measured for their physicochemical characteristics, such as X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) images, electron probe micro analyzer (EPMA) images, energy dispersive X-ray spectroscopy (EDXS), Brunauer-Emmett-Teller (BET) specific surface area, strength, and zinc content. Also, the samples were used in order to measure photochemical activities, such as the removal efficiency of humic acid (HA) in a fluidized batch reactor. The XRD patterns appeared as the ZnS type. The Zn-SPAC had a large BET specific surface area and their shape was spherical, with a diameter of about 350-400 lm. When the Zn-SPAC was dosed in a fluidized bed reactor with UV light, the HA removal efficiency increased by up to 60%. On the other hand, the HA removal efficiency by only UV-C (λmax = 254 nm) irradiation was very low, about 15%. Therefore, we infer that Zn-SPAC has good photochemical activity and presented the possibility of being a useful photocatalyst for water purification. © Springer Science+Business Media B.V. 2009.