The synthesis of spherical activated carbons containing zinc and their photochemical activity

Spherical activated carbon (AC) containing photocatalyst was prepared using strong and weak acid ion-exchange resins as starting materials. These resins were treated with an aqueous solution of Zn²⁺ or [Zn (NH₃)₄]^{2 +} and both treated resins and non-treated resins were carbonized and activated. The physicochemical characteristics of the AC samples were examined using XRD, SEM, EDS, BET, EPMA, ESR, compressive strength and zinc content. The photocatalytic activity was evaluated by measuring the humic acid (HA) removal efficiency using UV/photocatalyst system. When strong acid ion-exchange resins (SZ samples) were used to prepare AC containing zinc, the zinc was found to have ZnS crystal structures, whereas in case of the use of weak acid ion-exchange resins (WZ samples), the zinc was found to have ZnO crystal structure. Both the SZ and WZ samples had spherical shape except the WZ-A-900 and had a good BET specific surface area. In the HA removal test using a floating UV/photocatalyst system, the WZ samples showed higher HA removal efficiency than the SZ samples.