Easy preparation of nano iron oxides@ZnO as a magnetic separable photocatalyst for degradation of acid orange 7 from aqueous solution under visible light

摘要

In order to improve the photocatalytic activity and easy separation of ZnO from aqueous phase, nano iron oxides@ZnO (nFeO-ZnO) as a magnetic separable photocatalyst was prepared. First, the solution of iron (III) and (II) sulfates (2: 1 molar ratio) were stirred with ZnO powder in deionized distilled water for 2 h until ferric and ferrous sulfates adsorbed on ZnO, after which the suspension was heated to 323 K for 10 min. After heating, the solution was precipitated by ammonia solution with continuous stirring by mechanical stirrer at 373 K to produce nano iron oxides immobilized on ZnO (iron oxide@ZnO). Results of detailed phase analysis by XRD and scanning electron microscopy (SEM) are discussed. XRD analysis revealed that the crystallite size (mean coherence length) of iron oxides (mainly Fe2O3) was 35 nm. In the next step, the degradation of acid orang 7 (AO7) from aqueous solution by prepared nFeO-ZnO in the presence of visible light was investigated. The results showed that the photocatalytic activity of prepared magnetic separable photocatalyst compared with ZnO powder as a standard photocatalyst was increased in same operational condition. Also, photocatalyst can be separated easily from the aqueous solution by a magnet. The result showed the photodegradation followed pseudo first order kinetic and the activation energy of reaction was 3.89 KJ.mol(-1).