Effect of Al3+ substituted zinc ferrite on photocatalytic degradation of Orange I azo dye

•Al3+ substituted Zn ferrite was obtained by sol–gel auto-combustion method.•Photodegradation of aqueous solution of pollutant Orange I is reported.•Dye removal efficiency was enhanced with increase in Al3+ content in ZnFe2O4.•Dye removal efficiency was related to crystallite size and photoinduced processes.•First order kinetic constant after 45 min of irradiation, k was 2.37 × 10−2 min−1.

Aluminum substituted zinc ferrite catalysts were prepared by the sol–gel auto-combustion method and characterized by using Mössbauer spectroscopy and nitrogen adsorption–desorption isotherm measurements. The photocatalytic activity of ZnFe2−xAlxO4 (0 ≤ x ≤ 2) spinel ferrites was evaluated for the first time on Orange I azo dye degradation under UV light illumination. The results showed that the photocatalytic process was promoted when aluminum cations substituted iron cations located in octahedral sites of zinc ferrite lattice. Therefore, the Orange I azo dye best removal efficiency was observed when the Al3+ and Fe3+ are presents in equimolar amounts. The dye degradation performance of the ZnFe2−xAlxO4 (0 ≤ x ≤ 2) catalysts was related to the crystallite size than to the BET surface area values and to the presence of secondary phases, such as α-Fe2O3 and ZnO.

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