Enhanced degradation of Congo-red dye by Cr3+ doped α-Fe2O3 nano-particles under sunlight and industrial wastewater treatment

• Published in: Chemosphere (Oxford) 2023-12, Vol.343, p.140208-140208, Article 140208
• Main Authors: Yadav, Preety, Dhariwal, Neeraj, Kumari, Manju, Kumar, Vinod, Thakur, O.P.
• Format: Article
• Language: English
• Subjects: absorbance; active sites; catalysts; chromium; dyes; Fourier transform infrared spectroscopy; industrial wastewater treatment; nanocomposites; nanoparticles; photocatalysis; Photocatalyst; Reusability; solar radiation; transmission electron microscopy; ultraviolet-visible spectroscopy; water pollution; Water-waste; X-ray diffraction; X-ray photoelectron spectroscopy; α-Fe2O3
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.140208

Considering the increasing amount of water pollution, nanocomposite advances for the effective elimination of hazardous pollutants are still needed. α-Fe2O3, Cr0·5Fe1·5O3 and CrFeO3 nanoparticles were synthesized via an eco-friendly material synthesis i. e hydrothermal route without using any precipitating agent and were studied to remove congo-red dye using photocatalytic properties. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FESEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS) characterizations have been performed to know about the material structure and properties of synthesized samples. High efficiency (95.2%) of degradation was achieved under sunlight using a very low amount of CrFeO3 catalyst (0.2 g/L) at a 6-pH level of dye and was confirmed using UV spectroscopy, TOC (84%), LC-HRMS. Also, the potential to degrade the CR dye was concluded from the high rate of BOD5/COD. The results showed a significant enhancement in the degradation of α-Fe2O3 from 52.3% to 95.2% in a short duration of 15 min by introducing chromium as a dopant. The doping of chromium influenced the major factors responsible for the photocatalytic activity such as the increase in range of absorbance, increased e−-h+ pair separation, improvement in the charge transfer process and active site formation which significantly enhanced the process of degradation. We found that the Cr-doped α-Fe2O3 nanomaterial could effectively remove dyes, such as congo-red, from industrial water-waste. [Display omitted] •α-Fe2O3 and Cr doped α-Fe2O3 were synthesized via ecofriendly material synthesis method without using any precipitating agent.•The synthesized nanoparticles show high degradation rate of 95.2% in very short duration of 15 min under natural sunlight.•Very low amount of catalyst dosage was used for CR degradation making it very efficient and effective material.•Reusability and repeatability of the synthesized catalyst was also confirmed from the obtained results of XRD.•Azo dye contaminants present in industrial waste was also removed with the help of Cr doped α-Fe2O3 nanoparticles.