Corrosion of Copper in a Tropical Marine Atmosphere Rich in H2S Resulting from the Decomposition of Sargassum Algae
, Julien Pellé 2, Stéphane Rioual 2, Olivia Amintas 3, Carole Boullanger 3 and Christophe Roos 1
Round 1
Reviewer 1 Report
In the manuscript the interesting results concerning the chemical composition of the corrosion products formed on the copper are presented. The copper coupons were exposed in the sea environment for 1 year. The Sargassum algae were present in the sea and they produce the H2S. Therefore, the corrosion rate can be accelerated by the presence of S2- ions. The manuscript is correctlywrriten. The chemical mechanism of degradation of copper in the sea environment wit the presence of H2S gas was proposed. I sugget to authors to write the meachanism of degradation of copper in the presence of N3H gas. Because such gas can be produce by algae too.
Author Response
In the manuscript, the interesting results concerning the chemical composition of the corrosion products formed on the copper are presented. The copper coupons were exposed in the sea environment for 1 year. The Sargassum algae were present in the sea and they produce the H2S. Therefore, the corrosion rate can be accelerated by the presence of S2- ions. The manuscript is correctly written. The chemical mechanism of degradation of copper in the sea environment with the presence of H2S gas was proposed. I suggest to authors to write the mechanism of degradation of copper in the presence of N3H gas. Because such gas can be produce by algae too.
We thank the reviewer for their comments. We agree that NH3 gas is also emitted by seaweed degradation. However, our measurements show a very weak concentration of NH3 compared to H2S. This is confirmed by the reported corrosion products.
Reviewer 2 Report
The paper is interesting; however, the manuscript should be more refined, and I found many editorial errors. There are also unfinished sentences in the manuscript.
Figure 4, the scale is not visible
Line 30 “construction….” Lack of reference
Line 236 “…” Sentence without ending
Line 169 Figure. 1b.
i.e. Line 241 chemical equations should be edited (notation of chemical equations)
Double numbers of references in manuscript.
Author Response
The paper is interesting; however, the manuscript should be more refined, and I found many editorial errors. There are also unfinished sentences in the manuscript.
Figure 4, the scale is not visible
The scale bar is enlarged. The figure caption is completed: The scale bar corresponds to 500 mm.
Line 30 “construction….” Lack of reference
A reference has been added: L. Veleva, P. Quintana, R. Ramanauskas, R. Pomes and L. Maldonado, ‘Mechanism of copper patina formation in marine environments’, Electrochim. Acta, 41 (1996) 1641-1645.
Line 236 “…” Sentence without ending
The sentence was corrected: The possible anodic and cathodic reactions would in principle be as follows [29]
Line 169 Figure. 1b.
The point was removed.
i.e. Line 241 chemical equations should be edited (notation of chemical equations)
This is done.
Double numbers of references in manuscript.
This has been corrected.
We thank again the Reviewers for the suggestions to improve the quality of the manuscript. We addressed all comments.
Reviewer 3 Report
This paper investigated the corrosion of copper in a tropical marine atmosphere rich in H2S resulting from the decomposition of sargassum algae, which is very seldom studied. The paper is very novel and difinitely can be published in this journal after minor revision.
(1) since the author only show the surface mophology, the reviewer think the cross-sectional mophology is also very important, to show the thickness of the corrosion product layer and the elemental distribution.
(2) the format of the chemical reactions is not unified, please revise.
(3) in future work, I suggest the author can use electrochemical methods to identify the corrosion mechnism. Because electrochemical methods such as EIS is very useful to determine the corrosion mechnism.
(4) several important work should be mensioned.
[1] Yashar Behnamian et al. published in the Journal of The Electrochemical Society
[2] Digby Macdonald, Mehdi Amiri et al. published in Journal of Materials Science & Technology 2022
Author Response
This paper investigated the corrosion of copper in a tropical marine atmosphere rich in H2S resulting from the decomposition of sargassum algae, which is very seldom studied. The paper is very novel and definitely can be published in this journal after minor revision.
(1) since the author only show the surface mophology, the reviewer think the cross-sectional mophology is also very important, to show the thickness of the corrosion product layer and the elemental distribution.
We agree with the reviewer that cross-sectional analysis can be useful. However, in the studied case, samples were fully exposed to the harsh external conditions. The roughness of the exposed samples is very high and the corrosion products brittle. Thus, only a low magnitude SEM was used.
(2) the format of the chemical reactions is not unified, please revise.
This is done.
(3) in future work, I suggest the author can use electrochemical methods to identify the corrosion mechnism. Because electrochemical methods such as EIS is very useful to determine the corrosion mechnism.
We agree with the reviewer that electrochemical methods can be useful to study the corrosion mechanism. So, this work is in progress.
(4) several important work should be mensioned.
[1] Yashar Behnamian et al. published in the Journal of The Electrochemical Society
[2] Digby Macdonald, Mehdi Amiri et al. published in Journal of Materials Science & Technology 2022
Both articles are very interesting but our work is not based on EIS. It is therefore not easy to cite them.
We thank again the Reviewers for the suggestions to improve the quality of the manuscript. We addressed all comments.
Reviewer 4 Report
The paper needs completions. Though the authors speak about „corrosion rate” but only the thickness loss is demonstrated in Figure 3 and two numbers (page 5 line 170. „The values measured in Vauclin and Fregate est are 60 and 325 μm/year,…”) indicate the corrosion rate. There is nothing about the calculation and about the corrosion rate measured on all samples extracted from all four places.
There is not any word about the H2S concentration produced by sargassum seaweed. What were the differences on the four places of the experiments? How could the authors correlate with the composition of the corrosion products?
Page 7 line 276: „The existence of copper sulfite in corrosion products in H2S atmosphere” Not sulfide”? Equations 7-11 do not show the presence of SO32-. Later in the text the authors speak about the presence of CuSO3 and CuSO4, but not around the line 276.
Page 7 line 290: Is the molecular formula “Cu(SO)4(H2O)5.” correct?
Please, write the name of the “sargassum seaweed” uniformly, either with capital letter or with a small one.
Ref. [27] Please, correct the page numbers: 316-328
Author Response
The paper needs completions. Though the authors speak about „corrosion rate” but only the thickness loss is demonstrated in Figure 3 and two numbers (page 5 line 170. „The values measured in Vauclin and Fregate est are 60 and 325 μm/year …”) indicate the corrosion rate. There is nothing about the calculation and about the corrosion rate measured on all samples extracted from all four places.
The corrosion rate after 1-year exposure and the thickness loss dynamics are clearly separated. The calculation of the thickness loss is explained: The corrosion rate has been determined after 1-year exposure by measuring the copper thickness loss for each site. Firstly, the mass loss is obtained by the difference between the initial mass of the sample and the mass of the exposed sample after removal of corrosion the products. The thickness loss corresponds to the mass loss divided by the sample surface and copper density.
There is not any word about the H2S concentration produced by sargassum seaweed. What were the differences on the four places of the experiments? How could the authors correlate with the composition of the corrosion products?
The H2S concentration produced by sargassum seaweed depends on the quantity of algae. During this project, decomposition of few kilograms of sargassum seaweed immerged in seawater in lab conditions led to high concentration of more than 50 ppm at a distance of 50 cm. The observed differences in the corrosion process between the four places are clearly due the distance to the sea. The various corrosion products are consistent with this distance. Explanations are added in 2.1 part.
Page 7 line 276: „The existence of copper sulfite in corrosion products in H2S atmosphere” Not sulfide”? Equations 7-11 do not show the presence of SO32-. Later in the text the authors speak about the presence of CuSO3 and CuSO4, but not around the line 276.
The error is corrected. XRD data in Frégate est show the strong domination of CuS. Near the line 276, the formation of CuS is explained, whereas the formation of CuSO4.5H2O is described near line 290 without equation.
Page 7 line 290: Is the molecular formula “Cu(SO)4(H2O)5.” correct?
The molecular formula of sulfate copper pentahydrate CuSO4.5H2O is corrected in the text and in the figure.
Please, write the name of the “sargassum seaweed” uniformly, either with capital letter or with a small one.
This is corrected.
Ref. [27] Please, correct the page numbers: 316-328
This is corrected.
We thank again the Reviewers for the suggestions to improve the quality of the manuscript. We addressed all comments.
