Preparation, characterization and photocatalytic decolorization process for the removal of orange-green dye using perovskites Ba_1-xBi_xFeO_3-δ (x = 0, 0.05, 0.1)

Abstract

Recently, the preparation of novel nano-sized photocatalysts and studying of the ability of the prepared materials for the photocatalytic degradation of the harmful pollutants which often present in industrial effluents as model substances under solar/visible light paid particular attention. In this frame, nano-sized Ba_1-xBi_xFeO_3-δ system was prepared using Pechini method. All the samples are characterized using XRD, FTIR, optical absorbance spectra, TEM and BET. Cubic fluorite phase of BaFeO_2.75 was detected for BaFeO₃, Ba_0.95Bi_0.05FeO_3-δ samples while cubic fluorite phase of BaFeO₃ was detected for Ba_0.9Bi_0.1FeO_3-δ sample. Minor phases of Orthorhombic BaFe₂O₄, Monoclinic Ba₂Fe₂O₅ and Orthorhombic BaCO₃ were detected for all the samples. Bi doping had obvious effect on the cubic lattice parameter, the cubic unit cell volume, the optical properties, lattice spacing, surface area and the photocatalytic activity. pH, simulated solar irradiation time and catalyst dose were optimized to be 3, 420 min, and 1 g L⁻¹ respectively for degradation of 50 mg L⁻¹ dye, the highest decolorization efficiency was 92.2% using Ba_0.95Bi_0.05FeO_3-δ while, TOC removal was 90% for a photocatalytic and ammonia concentration attained 0.53 mg L⁻¹ under the optimum operating conditions. The photocatalytic decolorization of the dyes was fitted with pseudo first-order rate. According to scavenger experiment, the main oxidative species for the decolorization of orange green dye$\mathrm{}is\mathrm{}{O}_2^{•-}.$ The analysis of experimental design results demonstrated the significant effect of the irradiation time and pH for orange green on photocatalytic degradation process.

Keywords:

• Orange green
• Azo dye
• Ba_1-xBi_xFeO_3-δ
• Photocatalytic decolorization
• Perovskites
• sunlight
• active species

Acknowledgment

The authors are grateful to the Academy of Scientific Research and Technology (ASRT) of the Ministry of scientific research in Egypt and to the Ministry of Foreign Affairs and of the Research in France for founding this collaborative program (PHC Imhotep, 2016–2017, N° 35167NE). The Fonds Européen de Développement Régional (FEDER), CNRS, Région Hauts de-France, Chevreul Institute (FR 2638) and Ministère de l′Education Nationale de l′Enseignement Supérieur et de la Recherche are acknowledged for funding XRD instrument.

Disclosure statement

No potential conflict of interest was reported by the authors.