Photocatalytic degradation of dyes using phosphotungstate-hexamine hybrid under sunlight and UV irradiation: A combined experimental and DFT study

ABSTRACT

Dye adsorption and photocatalytic properties of the phosphotungstate-hexamine hybrid were examined by studying the decolourisation of model dyes methyl orange (MO) and methylene blue (MB) under ultraviolet and sunlight irradiation. Next, the effect of different factors including the initial concentration, pH, catalyst dosage, and H₂O₂ dosage, on decolourisation was investigated. The results show that the hybrid is a good heterogeneous photocatalyst for the degradation of MO and MB. For 10 mg/L MO, a degradation efficiency of about 90% was achieved in 35 min and 150 min under UV and solar light irradiation in the presence of 0.3 and 0.5 g/L hybrids at pH of 2.5, respectively. The degradation proceeded through photo-excitation of hybrid and dye, followed by decomposition or oxidation of dye by radicals. Quantum chemical calculations based on density functional theory (DFT) were carried out to obtain more information about the details of the electronic structures of the compounds and the interaction of hybrid with MO and MB dye molecules. The results show good agreement between calculated and experimental data.

KEYWORDS:

• Decolorisation
• dye
• photocatalyst
• polyoxometalate
• density functional theory

Acknowledgments

The authors express their appreciation to Payame Noor University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/2374068X.2022.2141670.