Photodegradation of Acid Violet 7 with AgBr–ZnO under highly alkaline conditions

The photocatalytic activity of AgBr–ZnO was investigated for the degradation of Acid Violet 7 (AV 7) in aqueous solution using UV-A light. AgBr–ZnO is found to be more efficient than commercial ZnO and prepared ZnO at pH 12 for the mineralization of AV 7. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization have been analyzed. Expect oxone, other oxidants decrease the degradation efficiency. Addition of metal ions and anions decrease the degradation efficiency of AgBr–ZnO significantly. The mineralization of AV 7 has also been confirmed by COD measurements. The mechanism of degradation by AgBr–ZnO is proposed to explain its higher activity under UV light. The catalyst is found to be reusable.

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► Photogenerated electron transfer from AgBr to ZnO increases charge separation.
► All the metal ions and anions decrease the dye degradation efficiency.
► Dye effluent under alkaline condition can be treated efficiently with AgBr–ZnO.
► Catalyst reusability makes this process more economical.