In a reaction like the Fenton process, which involves the use of Fe(III) and H2O2, does the concentration of Fe(II) species formed remain constant, whether there is water contamination or not?
For example, in the case of Fe(III)/H2O2/contaminant (0.5/0.5/0.05) mM, the concentration of Fe(II) formed is 0.3 mM after 60 minutes.
In the absence of a contaminant, with Fe(III)/H2O2 (0.5/0.5) mM, does the same amount of Fe(II) form after 60 minutes, or does it change?
Given that there is no reaction between the Fe(II/III) and the contaminant.
In a reaction like-Fenton Fe(III)/H2O2), the concentration of Fe(II) species formed can vary depending on various factors, such as the reaction conditions and water contamination
Here is a general approach to investigating this issue:
Monitor the reaction progress: Keep track of the mass of Fe(III) used and the amount of H2O2 consumed. These measurements will provide insights into the extent of the Fenton reaction and the generation of Fe(II) species.
Analyze the concentration of Fe(II) species: Measure the concentration of Fe(II) species in the solution during the reaction using appropriate analytical techniques, such as UV-Vis spectroscopy, or inductively coupled plasma mass spectrometry (ICP-MS).
The IUPAC definition of Fenton reaction
https://goldbook.iupac.org/terms/view/FT06786
Fe2+ + H2O2📷Fe3+ + OH· + OH−.
This is the iron-salt-dependent decomposition
of dihydrogen peroxide, generating the highly reactive hydroxyl radical, possibly via an oxoiron(IV) intermediate. Addition of a reducing agent, such as ascorbate, leads to a cycle which increases the damage to biological molecules.
See also Haber-Weiss reaction
Nadia Bougdour
Thank you for you answer, I just want to know if the Fenton-like reaction differs in producing fe(ii) in distilled water and water contaminated with pharmaceuticals without conducting the experiment, and I understood from your answer that water contamination can affect the production of fe(ii).
Nadia Bougdour and Badreddine Sellam
Fenton reaction is the reaction of 1 eq Fe(II) with 1 eq H2O2. Commonly, this reaction is fast. If H2O2 is an excess over Fe(II), the reaction mechanism includes so called Haber-Weiss cycle. The "Fenton-like reaction" is a very confusing term. Fe(III) is quickly hydrolyzed in distilled water producing insoluble iron-oxides. Contaminated water might be acidic or basic, might contain species forming stable complexes with Fe(II) and/or Fe(III). The generated HO(.) radical with contaminants affects the ratio of the steady state concentrations of Fe(II)/Fe(III).
Without having details of your experiment, your questions can't be answered. After dissolving 0.5 mM Fe(III) salt in water, the pH will drop to about 3 and some Fe(III)-oxides precipitate out. This process might be affected by contaminants.
Based exclusively on intuition, I would expect some precipitation of Fe(III), which would decrease the total amount of Fe. This amount could be affected by contaminants. The simplest experiment would be to check the initial and final pHs of solutions.
Yurii V Geletii Thank you very much, sir, for your detailed answer.
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