Photochemistry of the Fe(III)-iminodiacetic acid complex under UVA and UV/Vis irradiation: synthesis and characterisation

ABSTRACT

The photochemistry of Fe(III)-Iminodiacetic acid complex (Fe(III)-IDA) was studied under UVA and UV/Vis irradiation. The synthesis was realised via molar ratio method modified by reaction of IDA as ligand with Fe(III) as metal. The interaction of Fe(III) with IDA was characterised using Fourier-transform infrared (FTIR) and spectroscopy UV–visible. The results confirmed the stability of the complex at pH > 5; with constant of stability (Log β = 10.02) and stoichiometry Fe(III): IDA = 1:1. In addition, the redox potential was calculated at 521 mV, which is significantly lower than E° for the Fe(III)/Fe(II) couple. The photolysis of this complex in the presence of UVA light and UV/Vis light at different pHs was carried out. This photolysis was followed by several assay Fe(II) and ^•OH. The results show that the Fe(III)-IDA complex present a photo-reactivities under either light source and the phenomenon is faster when the UV/Vis was used. The initial conversion rate (r₀) decreased with increasing of initial pH. The formation of hydroxyl radicals via the Fenton reaction was improved at pH = 2.12 for both irradiation sources used. Reduction of total organic carbon was also studied using the total organic carbon (TOC). The feasibility of amino iron complexes to improve the Fenton process under irradiation was confirmed. Additionally, our research also evidenced the optimal conditions for the formation of hydroxyl radicals; which are the key factor in remove pharmaceuticals pollutants in aqueous media. Based on the results obtained, the Fe(III)-IDA complex could be efficiently photolysis under UV/Vis light.

GRAPHICAL ABSTRACT

KEYWORDS:

• Complex Fe(III)-IDA
• UVA
• UV-Vis
• photolyse
• hydroxyl radicals

Acknowledgements

The authors would like to thank the Algerian Ministry of Higher Education and Scientific Research for the financial supporting. We wish to thank Laboratoire de Cristallographie, Département de Physique, Faculté des Sciences Exactes, Université Frères Mentouri Constantine 1, Algeria, for the use of a Fourier-transform infrared spectrophotometer JASCO (FT/IR-6300) to determine the functional groups of the samples.

Disclosure statement

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

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article [and/or] its supplementary materials.