Highly active Zr co-doped Ag–ZnO photocatalyst for the mineralization of Acid Black 1 under UV-A light illumination

The Zr co-doped Ag–ZnO (Zr–Ag–ZnO) was successfully synthesized by precipitation–decomposition method. The photocatalytic activity of Zr–Ag–ZnO was investigated for the degradation of Acid Black 1 (AB 1) in aqueous solution using UV-A light. Co-dopants shift the absorbance of ZnO, both in UV and visible region. Zr–Ag–ZnO is found to be more efficient than Ag–ZnO, Zr–ZnO, commercial ZnO, prepared ZnO, TiO2–P25 and TiO2 (Merck) at pH 9 for the mineralization of AB 1 under UV-A light. The influence of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of AB 1 has been analyzed. The mineralization of AB 1 has been confirmed by COD measurements. Mechanism of degradation by Zr–Ag–ZnO is proposed. The catalyst is found to be reusable.