Circular Management of Lavandula stoechas L. Post-Phytoremediation of Contaminated Soils—From Essential Oil to Potential Biochar for Supercapacitors

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Circular Management of Lavandula Stoechas L. Post-Phytoremediation of Contaminated Soils. from Essential Oil to Biochar for Supercapacitors

1. What is the role of Pb, Zn and Tl in supercapacitor application? Author should explain it in introduction section (No-94).
2. The instruments used for characterization in this study should be described in a separate instrumentation section, not include in Biochar Synthesis part. (No-202 to 207)
3. Out of curiosity, have the authors tested by different permutation for Pb, Zn and Tl concentration. Like Pb_AZn_BTl, Pb_cZn_ATl or Pb_BZn_ATl etc.
4. The caption of Fig-1 is insufficient. Author should expand it to a clear description of the data presented, the meaning of the axes, and statical information.
5. In Fig-4, since microporosity is determined in the 0-2 nm region, please mention clear unit interval on the X-axis of BJH plot (at least 2-3 marking), so that the pore diameter values can be easily identified. (No-372 to 374).
6. Author should explain a clear caption of the data presented of Fig-6.
7. In Fig-7, author should mention the compound name in the graph (like-Biochar Ash or Biochar@1000)
8. As the biochar showing higher microporosity than mesoporosity, how does this affect its supercapacitor Performance? (No-384 to 390)
9. What is the ID/IG ratio of biochar shown in Fig-8? What is the significance of that ratio?

10. As the title suggests preparation of biochar for supercapacitor application, author should include Cyclic voltammetry (CV), Galvanostatic Charge Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) studies to demonstrate specific capacitance, resistance in the electrode-electrolyte interface and stability. 

Comments for author File: Comments.pdf

Author Response

Open Review 1

Coment 1: What is the role of Pb, Zn and Tl in supercapacitor application? Author should explain it in introduction section (No-94). 

Response 1: Thank you for your suggestion. A paragraph (L.102-119) has been added in the introduction section explaining the role of these metals (Pb, Zn and Tl) in anode optimization and device stability.

Coment 2: The instruments used for characterization in this study should be described in a separate instrumentation section, not include in Biochar Synthesis part. (No-202 to 207)

Response 2 We appreciate the reviewer's suggestion regarding the organization of the manuscript. Following his recommendation, the description of biochar synthesis focuses exclusively on the methodological procedure (temperatures, times, heating rate and flow rate). On the other hand, we have created a new section (L. 272) entitled 2.5.1. Characterization and Instrumentation, where the models of the equipment, the commercial companies and the technical conditions of the measurements (SEM, BET, XPS, etc.) are detailed.

Coment 3: Out of curiosity, have the authors tested by different permutation for Pb, Zn and Tl concentration. Like Pb_AZn_BTl, Pb_cZn_ATl or Pb_BZn_ATl etc.     

Response 3: Without any doubt, the reviewer's suggestion is valuable and represents a very promising future line of research to understand the competitive interferences between these three metals during pyrolysis. However, testing all combinations of Pb, Zn and Tl concentrations exceeds the initial objectives of this work, which seeks to establish the fundamental relationship between phytoremediation and the quality of biomass once pyrolyzed, as well as if the metal content is optimal for use in supercapacitors. The selected concentrations in this study were based on the levels of metals found in the study area (1,2).

1. González-Morales, M.; Rodríguez-González, M.Á.; Fernández-Pozo, L. Status of Ecosystem Services in Abandoned Mining Areas in the Iberian Peninsula: Management Proposal. Toxics 2023, 11, 275, doi:10.3390/toxics11030275.
2. González-Morales, M.; Fernández-Pozo, L.; Rodríguez-González, M.Á. Threats of Metal Mining on Ecosystem Services. Conservation Proposals. Environmental Research 2022, 214, 114036, doi:10.1016/j.envres.2022.114036.

Coment 4: The caption of Fig-1 is insufficient. Author should expand it to a clear description of the data presented, the meaning of the axes, and statical information.   

Response 4: Thank you for the comment. It must be a typographical error, because in an earlier version of the manuscript the complete figure caption appeared. The figure caption (L. 285-286) has been completed.

Coment 5: In Fig-4, since microporosity is determined in the 0-2 nm region, please mention clear unit interval on the X-axis of BJH plot (at least 2-3 marking), so that the pore diameter values can be easily identified. (No-372 to 374).

Response 5: Thank you for your feedback. Figure 4 has been modified.

 

Coment 6: Author should explain a clear caption of the data presented of Fig-6 

Response 6: Thank you for this notion. Figure 6 has been modified, explained and introduced new bibliography (54-56) for better explanation.

Coment 7: In Fig-7, author should mention the compound name in the graph (like-Biochar Ash or Biochar@1000)                

Response 7: Thank you for this notion. Figure 7 has been modified.

Coment 8: As the biochar showing higher microporosity than mesoporosity, how does this affect its supercapacitor Performance? (No-384 to 390)                       

Response 8:  Thank you very much for your comment. New paragraph has been included in the reviewed manuscript (L. 454-463).

Coment 9: What is the ID/IG ratio of biochar shown in Fig-8? What is the significance of that ratio?     

Response 9: Thank you for you coment. A new paragraph has been included in the discussion (L. 502-517) and bands D and G marked in Figure 8 for better understanding.

Coment 10: As the title suggests preparation of biochar for supercapacitor application, author should include Cyclic voltammetry (CV), Galvanostatic Charge Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) studies to demonstrate specific capacitance, resistance in the electrode-electrolyte interface and stability. 

Response 10: We appreciate the reviewer's valuable suggestion. We understand that CV, GCD, and EIS testing are critical to characterizing a complete energy storage device and are being discussed for a new article. However, this manuscript aims to evaluate the possibility of transforming contaminated biomass into a carbonaceous material with suitable properties (high porosity and hierarchical pores) for future electrochemical application. This work is a preliminary study focused on the synthesis and structural/textural characterization of biochar (surface area, porosity and functional groups), which are the critical conditions that validate if the material has the necessary architecture for ion transport and use in supercapacitors. To avoid confusion about the scope, we have changed slightly the title to: Circular Management of Lavandula stoechas L. Post-Phytoremediation of Contaminated Soils. From Essential Oil to Potential Biochar for Supercapacitors. In this way, the article is presented as a materials science study that places the foundations for the electrochemical tests mentioned by the reviewer.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Title

1. Scientific name should be in italics

Abstract

2. Missing quantitative highlights (e.g., BAF, TF, SSA relevance). Include specific numerical results tied to conclusions.

Introduction

3. The rationale for selecting the plant species needs stronger justification.
4. The circular economy concept is introduced but not sufficiently linked to a specific scientific problem.
5. Clarify the novelty of integrating phytoremediation with biomass valorization

M&M

6. The relationship between pots, plants, and replicates needs clarification.
7. It is not fully clear whether the analysis was conducted at the plant level or pot level.
8. Clarify: (A) number of biological replicates; (B) experimental unit; (C) randomization procedure; (D) blocking structure
9. Add a brief statement describing quality assurance and quality control procedures.
10. Section 2.3: Clarify: (A) why experimental plants were not used (B) whether environmental conditions were comparable; (C) how sampling consistency was ensured
11. Section 2.4: Provide: assumption testing; effect size; confidence intervals; treatment of repeated measurements
12. Section 2.5: key operational parameters are missing. Provide: heating rate; residence time; particle size; biochar yield

R&D

13. Section 3.2: The discussion of accumulation mechanisms is limited. Results would benefit from comparison with literature values.
14. Section 3.3: This section includes statements about pharmacological or therapeutic effects of compounds that were not evaluated in this study. Avoid claims related to: medicinal effects, health benefits and therapeutic properties. Better to limit the discussion to chemical composition, safety assessment and contamination risk.
15. Section 3.4: The link between measured properties and proposed applications (e.g., supercapacitors) is not sufficiently demonstrated.

Conclusion

16. The conclusions extend beyond the data in several places.
17. Some claims imply environmental or industrial implementation without supporting evidence.

Figure 1 and Table 2, 3, 5: Provide statistical information.

Author Response

Open Review 2

Coment 1: Scientific name should be in italics

Response 1: Scientific name have been revised.

Coment 2 (Abstract): Missing quantitative highlights (e.g., BAF, TF, SSA relevance). Include specific numerical results tied to conclusions.

Response 2: Thank you very much for your comment. The Abstract has been modified to include the indicated data.

Coment 3 (Introduction): The rationale for selecting the plant species needs stronger justification.

Response 3 (Introduction): We appreciate the reviewer's comment. We have added a paragraph in the introduction section to give greater strength to the selection of this species (L. 84-91).

Coment 4 (Introduction): The circular economy concept is introduced but not sufficiently linked to a specific scientific problem.

Response 4 (Introduction): We appreciate the reviewer's observation. We have added a paragraph in the introduction section to reinforce this idea (L. 120-129).

Coment 5 (Introduction): Clarify the novelty of integrating phytoremediation with biomass valorization

Response 5 (Introduction) We welcome the reviewer's comment. The novelty of this work transcends the mere combination of both techniques, since it is shown that biomass contaminated with Pb, Zn or Tl, after phytoremediation, does not require expensive hazardous waste management, but can be converted into carbonaceous materials of high energy density after pyrolysis, like supercapacitors. In addition, metals present in plant tissues increase energy storage compared to uncontaminated biomass.

Coment 6 (M&M): The relationship between pots, plants, and replicates needs clarification.

Response 6 (M&M): Thank you for your coment. A new paragraph has been added to clarify this relationship (L. 177-187).

Coment 7 (M&M): It is not fully clear whether the analysis was conducted at the plant level or pot level.

Response 7 (M&M): Thank you for your coment. A new paragraph has been added to clarify this relationship (L. 177-187).

Coment 8 (M&M): Clarify: (A) number of biological replicates; (B) experimental unit; (C) randomization procedure; (D) blocking structure

Response 8 (M&M): We appreciate the observation. We have clarified the structure of the experimental design (L. 177-187) and changed the chemical formulas to the structural form.

Coment 9 (M&M): Add a brief statement describing quality assurance and quality control procedures.

Response 9 (M&M): Thank you for your coment. A new paragraph has been added to clarify this relationship (L177-187).

Coment 10 (M&M): Section 2.3: Clarify: (A) why experimental plants were not used (B) whether environmental conditions were comparable; (C) how sampling consistency was ensured

Response 10 (M&M): Thank you for your comment. A paragraph (L. 161-176) has been added to ensure the validity of the experiment.

Coment 11 (M&M): Section 2.4: Provide: assumption testing; effect size; confidence intervals; treatment of repeated measurements

Response 11 (M&M):Thank you. Section 2.4 has been rewritten in order to include the required data and better understanding.

Coment 12 (M&M): Section 2.5: key operational parameters are missing. Provide: heating rate; residence time; particle size; biochar yield

Response 12 (M&M): We appreciate the observation. We have completed section 2.5. Biochar Synthesis including the omitted operating parameters to ensure the reproducibility of the experiment. Added details on the heating ramp, particle size after grinding, and cooling method (L. 264-271).

Coment 13 (R&D): Section 3.2: The discussion of accumulation mechanisms is limited. Results would benefit from comparison with literature values.

Response 13 (R&D): Thank you very much for your feedback. Section 3.2. Study of heavy metals(oid)s content has been rewritten focusing on the mechanisms of accumulation and tolerance to heavy metals, and leaching dynamics. Recent bibliography has been included.

Coment 14 (R&D): Section 3.3: This section includes statements about pharmacological or therapeutic effects of compounds that were not evaluated in this study. Avoid claims related to: medicinal effects, health benefits and therapeutic properties. Better to limit the discussion to chemical composition, safety assessment and contamination risk.

Response14 (R&D): We appreciate and accept the reviewer's observation. We agree that the focus of this study should be on the chemical characterization and environmental safety of the recovered biomass. Following your recommendation, we have thoroughly revised Section 3.3, removing any claims regarding the therapeutic properties, pharmacological effects, or health benefits of the identified compounds. The discussion has been reoriented exclusively towards the composition of the essential oil and the risk assessment of contaminant (metal) transfer, including more recent bibliography.

Coment 15 (R&D): Section 3.4: The link between measured properties and proposed applications (e.g., supercapacitors) is not sufficiently demonstrated.

Response15 (R&D): We appreciate the reviewer's valuable suggestion. We understand that CV, GCD, and EIS are critical parameters to characterizing a complete energy storage device and are being discussed in a new article. This work is a preliminary study focused on the synthesis and structural/textural characterization of biochar (surface area, porosity and functional groups), which are the very important prerequisites that validate whether the material possesses the necessary architecture for ion transport and can be used in supercapacitor technologies. Electrode efficiency in supercapacitors requires a balance between electron transport, accessible porosity (SSA of 393.7 m²/g), and the stability of the electrical double layer. To avoid confusion about the scope, we have included a paragraph to reflect that these values are preliminary and that future optimization stages (such as doping or thermal activation) could raise this performance (Section 3.5, L. 548-557). We have also changed slightly the title to: Circular Management of Lavandula stoechas L. Post-Phytoremediation of Contaminated Soils. From Essential Oil to Potential Biochar for Supercapacitors. In this way, the article is presented as a materials science study that lays the foundations for the electrochemical tests mentioned by the reviewer.

Coment 16 (Conclusion): The conclusions extend beyond the data in several places.

Response 16 (Conclusion): Than you. Conclusions have been rewritten.

Coment 17 (Conclusion): Some claims imply environmental or industrial implementation without supporting evidence.

Response 17 (Conclusion): We appreciate the observation. We recognize that the language used in the original conclusions suggested an immediate implementation that exceeds the experimental data obtained. We have rewritten the conclusions to adopt a more technical character because we have not carried out clinical or industrial safety tests.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. The experimental design is described superficially. Key details on randomization, control, and replication are not provided, which makes it impossible to assess the validity of the differences between the groups.
2. The writing of formulas is surprising: PbN2O6, ZnN2O6 × 6H2O. Why is it not so: Pb(NO3)2, Zn(NO3)2×6H2O?
3. Pb (48, 60 and 1500 ppm), Zn (281, 351 and 700 ppm) and Tl (1, 1.25 and 700 ppm) – What is the rationale for choosing such intermediate values ???
4. In a number of sections (for example, in the analysis of morphological and physiological parameters of plants), the use of nonparametric tests (Kruskal-Wallis, Dunnett's T3) is noted, but it is not always clear why alternative methods of analysis were not used, given the sample size and the nature of the data distribution.
5. The tables and graphs do not always indicate standard deviations or confidence intervals, which makes it difficult to assess the spread of data and reproducibility of results.
6. Tables and figures are overloaded, not always signed, and sometimes contain internal contradictions. For example, tables with metal content in soil and plants contain values that do not match the trends described in the text.
7. The safety of essential oil and hydrosol is declared by the authors based on the absence of metals in the final products. However, no study has been conducted on the possible accumulation of organic pollutants or heavy metal transformation products during distillation. Such claims require a deeper toxicological justification.
8. The fate of heavy metals in biochar has not been studied. The authors ignore the risk of Pb, Zn, and Tl leaching from the biochar during its operation in supercapacitors or when released into the environment. This makes the use of the material potentially dangerous and contrary to the principles of circular economy.
9. The laboratory scale of the production of essential oil and biochar is described, but the issues of scaling processes for industrial implementation are not discussed.
10. Morphometric and physiological data are interpreted ambiguously. The authors conclude that the plant is highly resistant to pollution, but they do not take into account the possible influence of greenhouse conditions and limited soil volume on the development of the root system.
11. The use of biochar in supercapacitors is stated as promising, but is not supported by the actual electrochemical characteristics of the material (capacity, cycle stability, internal resistance). The reduced electrical conductivity (35 S/cm) is not unique to carbon materials and does not guarantee high efficiency of the electrode.
12. The list of references contains outdated or irrelevant sources, as well as works that are not directly related to the research topic.

Comments for author File: Comments.pdf

Author Response

Open Review 3

Coment 1: The experimental design is described superficially. Key details on randomization, control, and replication are not provided, which makes it impossible to assess the validity of the differences between the groups.                      

Response 1: We appreciate the observation. We have clarified the structure of the experimental design (L. 177-187) and changed the chemical formulas to the structural form.

Coment 2: The writing of formulas is surprising: PbN2O6, ZnN2O6 × 6H2O. Why is it not so: Pb(NO3)2, Zn(NO3)2×6H2O?            

Renponse 2: We sincerely thank the reviewer for this observation. We recognize that the notation originally used (PbN₂O₆) was an inaccurate molecular representation that did not adequately reflect the chemical structure of the compound (nitrate). We have corrected all the chemical formulas in the manuscript, adopting the standard nomenclature Pb(NO₃)₂ and Zn(NO₃)₂.6H₂O. This correction allows the correct identification of the functional groups (nitrates) and the hydration status of the used salts, improving the clarity and technical rigor of the text, especially in the “Materials and Methods section.

Coment 3: Pb (48, 60 and 1500 ppm), Zn (281, 351 and 700 ppm) and Tl (1, 1.25 and 700 ppm) – What is the rationale for choosing such intermediate values ???

Response 3: We appreciate the reviewer observation. We understand that the choice of intermediate (B) levels requires a more solid justification beyond discretion. The maximum concentration levels (C) were based on the peak values recorded in abandoned mining areas [4,5]. In contrast, intermediate concentrations (B) were established to represent moderate contamination scenarios, common in mine site buffer zones. This selection allows the evaluation of the response of L. stoechas along a representative pollution gradient, ranging from regulatory limits (A) to extreme environmental hotspots (C). We have modified the text in lines 150-159 to increase the detail of the environmental logic of these limits.

Coment 4: In a number of sections (for example, in the analysis of morphological and physiological parameters of plants), the use of nonparametric tests (Kruskal-Wallis, Dunnett's T3) is noted, but it is not always clear why alternative methods of analysis were not used, given the sample size and the nature of the data distribution.

Response 4: Thank youfor your coment. Section 2.4 has been rewritten for better understanding.

Coment 5: The tables and graphs do not always indicate standard deviations or confidence intervals, which makes it difficult to assess the spread of data and reproducibility of results.

Response 5: Tables and graphs of the supplementary material have been corrected.

Coment 6: Tables and figures are overloaded, not always signed, and sometimes contain internal contradictions. For example, tables with metal content in soil and plants contain values that do not match the trends described in the text.

Response 6: We appreciate the meticulous review of the data presented. We acknowledge that there were typographical discrepancies between some tables which have been corrected in this new version.

Coment 7: The safety of essential oil and hydrosol is declared by the authors based on the absence of metals in the final products. However, no study has been conducted on the possible accumulation of organic pollutants or heavy metal transformation products during distillation. Such claims require a deeper toxicological justification.  

Response 7: We appreciate the reviewer's observation about the complexity of the residual matrix. Any claims regarding the therapeutic properties, pharmacological effects or health benefits of the identified compounds have been removed. Regarding the toxicological safety of essential oil and hydrolat, we want to indicate the following. The soil is contaminated by strictly mineral (metal mining), with no synthetic organic compounds (hydrocarbons or pesticides), which drastically reduces the probability of volatile organic pollutants in the plant material. The "metal transformations" usually occur in high-temperature processes (pyrolysis at 600ºC) or by bacteria at the bottom of a swamp (methylation), but not in a pot of boiling water. The safety of distillation products is based on the low volatility of the inorganic species of Pb, Zn and Tl at the boiling temperature of water (100ºC), which prevents it from being carried into the condensate. The chromatographic profiles obtained (GC-MS) confirm that the majority constituents correspond to natural secondary metabolites of L. stoechas, without evidence of formation of thermal transformation products derived from the interaction with heavy metals.

Coment 8: The fate of heavy metals in biochar has not been studied. The authors ignore the risk of Pb, Zn, and Tl leaching from the biochar during its operation in supercapacitors or when released into the environment. This makes the use of the material potentially dangerous and contrary to the principles of circular economy.

Response 8: We understand the reviewer's concern because the work focuses on the circular economy. The scientific literature shows that the pyrolysis at high temperatures (in our case, 1000ºC for Raman analysis and 600ºC for synthesis) promotes the speciation of metals towards more stable forms (such as sulfides or silicates) and their physical encapsulation within the carbon matrix, being mechanically trapped by the shrinkage of the lignin and cellulose structure when converted into amorphous and graphitic carbon (1, 2, 3). In energy storage applications, this immobilization is a key to preventing electrolyte contamination maintaining the structural integrity of the electrode. Within a circular economy model, biochar is not released into the environment at the end of its useful life, and these devices are managed as electronic waste (e-waste) for component recovery, avoiding uncontrolled leaching.

1. Jalal Bayar, Nawab Ali, Younsuk Dong et al. Biochar based adsorption for heavy metal removal in water:a sustainable and cost effective approach. Environ Geochem Health (2024) 46:428 https://doi.org/10.1007/s10653-024-02214-w
2. Maria Rosaria Boni, Agostina Chiavola and Simone Marzeddu. Application of Biochar to the Remediation of Pb-Contaminated Solutions. Sustainability 2018, 10(12), 4440; https://doi.org/10.3390/su10124440
3. Man Zhao, Yuan Dai, Miaoyue Zhang et al. Mechanisms of Pb and/or Zn adsorption by different biochars: Biochar characteristics, stability, and binding energies. Sci Total Environ. 2020 ,717:136894. https://doi.org/10.1016/j.scitotenv.2020.136894

 

 

Coment 9: The laboratory scale of the production of essential oil and biochar is described, but the issues of scaling processes for industrial implementation are not discussed.

Response 9: We agree that industrial scaling is the next logical step. However, this study was designed as a proof of concept (TRL 3) to establish some fundamental parameters such as oil yield and biochar stability, which are technically unknown for this specific biomass (lavender). These laboratory data are prior to any engineering design or large-scale economic feasibility analysis, because other factors such as mass and energy transfer would have to be considered. We consider that a detailed analysis of the industrial scale-up exceeds the scope of the present manuscript, whose main objective is to validate the technical and chemical feasibility at the laboratory scale.

Coment 10: Morphometric and physiological data are interpreted ambiguously. The authors conclude that the plant is highly resistant to pollution, but they do not take into account the possible influence of greenhouse conditions and limited soil volume on the development of the root system.

Response 10: Thank you for your comment on the growing conditions. We agree that the greenhouse environment and the volume of substrate (750 g) impose different conditions from those of a natural ecosystem. However, the objective of the study was not to evaluate full ecological development, but to perform a controlled dose-response bioassay to determine the specific tolerance of L. stoechas to metal toxicity. Greenhouse conditions were kept constant (photoperiod, irrigation, and temperature) to ensure that any morphometric changes were exclusively attributable to the Pb, Zn, and Tl contamination gradient. We agree that pot volume can limit long-term root expansion, but for the duration of this experiment (90 days), soil volume was sufficient to allow for intimate root-soil interaction and stabilization of metals, as evidenced by root accumulation data. We have added a note in Section 3.1 (Discussion, lines 320-326) acknowledging these scale limitations and suggesting that future field studies (in situ trials) are necessary to validate the resistance of the species under ecological competition and real water stress.

Coment 11: The use of biochar in supercapacitors is stated as promising, but is not supported by the actual electrochemical characteristics of the material (capacity, cycle stability, internal resistance). The reduced electrical conductivity (35 S/cm) is not unique to carbon materials and does not guarantee high efficiency of the electrode.

Response 11: We appreciate the reviewer's valuable suggestion. We understand that CV, GCD, and EIS testing are essential to characterizing a complete energy storage device, and are being discussed for a later article. We agree that a conductivity of 35 S/cm is modest compared to highly engineered synthetic carbons, but it should be noted that the biochar was obtained from residual phytoremediation biomass without subsequent chemical activation processes. For a lignocellulose-derived carbon material, 35 S/cm represents a competitive value indicating sufficient electronic percolation for low- to moderate-power energy storage applications. The aim of this work is not to maximize the conductivity, but to demonstrate that the material retains functional electrical properties despite the presence of encapsulated heavy metals. The efficiency of the electrode in supercapacitors does not depend exclusively on intrinsic conductivity, but on the balance between electron transport, accessible porosity (SSA of 393.7 m²/g) and the stability of the electrical double layer. We have included a paragraph to reflect that these values are preliminary and that future optimisation stages (such as doping or thermal activation) could raise this performance (Section43.5, lines 548-557).

Coment 12: The list of references contains outdated or irrelevant sources, as well as works that are not directly related to the research topic.

Response 12: We appreciate the reviewer's comment related to the references. We understand the importance of including recent literature in this dynamic field. Following their recommendation, we have incorporated (approximately) 14 new references from the period 2021-2025 in the Introduction and Discussion sections that reinforce our findings with state-of-the-art phytoremediation and energy storage data, balancing the historical fundamentals with the current state of the art."

But some citations from 2015 or earlier have been maintained because both research and conclusions remain relevant, and no evidence has been reported to refute their results.

 

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Comments to the Author:

Title: Circular Management of Lavandula stoechas L. Post- Phytoremediation of Contaminated Soils from Essential Oil to Biochar for Supercapacitors

 

Overview and general recommendation:

The manuscript deals with an important topic related to the circular management of Lavandula stoechas L. post-phytoremediation of contaminated soils from essential oil to biochar for supercapacitors. The manuscript technically sounds well and shows high novelty. However, it needs major linguistic adjustments; therefore, I invite the authors to pass their manuscript to a native English speaker for editing and revision. In this regard, the needed adjustments are highlighted in “Minor comments” section. Also, numerous statements show old sources (references) that should be replaced by more recent ones (last five years of publication).

The Abstract part outlines clearly the problematic, aims, methodology and findings of the current study while reporting the main conclusions aroused. However, authors shall better outline the adopted methodology. Therefore, it can be reformulated in a more appropriate manner. The Introduction section is well structured and aiming and underlines appropriately the whole subject under study. The aims of the study are also clear and understood. The Materials and Methods section is generally clear, well written, and encloses most of the information related to the adopted methodology, and statistical analysis. However, the adopted methodology in paragraph 2.2. shall be briefly explained. Although it shows sometimes a correct statistical representation, the Results and Discussion section needs major adjustments. In paragraph 3.1., the scientific analysis of the findings should be well improved. Percentages of variation (improvements/decreases) should be highlighted. While, in paragraph 3.2., the outline of significance differences through statistical letters in tables should be performed. Also, the scientific analysis of the findings should be adjusted accordingly; percentages of variation (improvements/decreases) should be highlighted. Whereas, in paragraph 3.3., more recent studies (last five years of publication if possible) are needed to discuss the obtained findings and a better performance of the discussion is urged. A more concise Conclusions section shall be provided in a way that much better summarize the findings of the study. Authors shall also suggest further related research being based on the raised assumptions.

My comments and queries for authors are detailed below in “Major comments” and “Minor comments” sections.

 

Major comments: 

1. The manuscript needs major linguistic adjustments; accordingly, I invite the authors to pass their manuscript to a native English speaker for editing and revision. Most needed adjustments are highlighted in “Minor comments” section.
2. Numerous statements show old sources (references) that should be replaced by more recent ones (last five years of publication).
3. Abstract: The Abstract section can be reformulated in a more appropriate manner.
4. Materials and Methods, 2.2. Measurement of metal content: Kindly describe briefly the adopted methodology.
5. Results and Discussion, 3.1. Morphometry: The scientific analysis of the findings should be well improved. Percentages of variation (improvements/decreases)should be highlighted.
6. Results and Discussion, 3.2. Study of heavy metal(loid)s content: The outline of significance differences through statistical letters in tables should be performed. Also, the scientific analysis of the findings should be adjusted accordingly; percentages of variation (improvements/decreases)should be highlighted.
7. Results and Discussion, 3.3. Essential oil extraction: Page 11, lines 348-354: More recent studies (last five years of publication if possible) are needed to discuss the obtained findings and a better performance of the discussion is urged.
8. Conclusions: Amore concise Conclusions section shall be provided in a way that much better summarize the findings of the study. Authors shall also suggest further related research being based on the raised assumptions.

 

Minor comments:

1. Abstract: Page 1, line 14: Kindly adjust as follow: “proposed”.
2. Abstract: Page 1, line 17: Kindly adjust as follow: “retained”.
3. Abstract: Page 1, line 19: Kindly adjust as follow: “focused”.
4. Abstract: Page 1, line 20: Kindly remove “as”.
5. Abstract: Page 1, lines 21-24: “These products… biochar”: These sentences are badly written in standard English; accordingly, kindly reformulate them.
6. Abstract: Page 1, line 26: Kindly adjust as follow: “validated”.
7. Keywords: Page 1, line 29: Kindly write the Latin name in Italic form.
8. Introduction: Page 1, lines 32-34: “Mining… [1]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
9. Introduction: Pages 1-2, lines 40-43: “Although… tissues”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
10. Introduction: Page 2, line 52: Kindly write the family name in Italic form.
11. Introduction: Page 2, lines 54-55: “It blooms… [13]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
12. Introduction: Page 2, lines 62-65: “Several… [15,16]”: Same recommendation as in the previous comment regarding reference number 16.
13. Introduction: Page 2, line 69: Reference number 20 is incomplete in the list of references; accordingly, kindly adjust it.
14. Introduction: Page 2, line 72: Kindly adjust as follow: “stated”.
15. Introduction: Page 2, line 74: Kindly adjust as follow: “proposed”.
16. Introduction: Page 2, lines 74-75: References numbers 24 and 25 are old; accordingly, kindly replace them by more recent ones (last five years of publication).
17. Introduction: Page 2, lines 81-83: “However… [27]”: Same recommendation as in the previous comment.
18. Introduction: Page 2, line 84: Kindly write the Latin name in Italic form.
19. Introduction: Page 3, lines 96-98: “The investigation… applications”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
20. Materials and Methods, 2.1. Phytoremediation experiment, 2.1.1. Experimental design: Page 3, line 117: Kindly adjust as follow: “[4,5]”.
21. Materials and Methods, 2.1. Phytoremediation experiment, 2.1.1. Experimental design: Page 3, line 126: Kindly adjust as follow: “the other three”.
22. Materials and Methods, 2.5. Biochar synthesis: Page 5, lines 195-200: “It is important… atmosphere”: The sentence is long and cumbersome; accordingly, kindly reformulate in order to make it more concise, clearer, and more aiming.
23. Results and Discussion, 3.1. Morphometry: Page 6, line 218: Kindly adjust as follow: “inhibited”.
24. Results and Discussion, 3.1. Morphometry: Page 6, line 223: Kindly adjust as follow: “decreased”.
25. Results and Discussion, 3.1. Morphometry: Page 6, lines 226-227: “Similar… stress”: References used for this statement are old; accordingly, kindly replace them by more recent ones (last five years of publication).
26. Results and Discussion, 3.1. Morphometry: Page 6, line 234: Kindly replace “take” by “took”.
27. Results and Discussion, 3.1. Morphometry: Page 7, lines 236-238: “Due to… observed”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
28. Results and Discussion, 3.1. Morphometry: Page 7, line 239: Kindly replace “is” by “was”.
29. Results and Discussion, 3.1. Morphometry: Page 7, lines 244-245: Kindly replace “is” by “was”.
30. Results and Discussion, 3.1. Morphometry: Page 7, lines 246-248: “Regarding… metal(loid)s”: Kindly adopt the past verbal tense form for these sentences.
31. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 263: Kindly adjust as follow: “remained”.
32. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 264: Kindly adjust as follow: “accumulated”.
33. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, lines 265-267: “Pb… [36]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
34. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 267: Kindly adjust as follow: “demonstrated”.
35. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 271: Kindly adjust as follow: “indicated”.
36. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 272: Kindly replace “are” by “were”.
37. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 274: Kindly adjust as follow: “suggested”.
38. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, lines 287-288: “Similar… [38]”: Reference number 36 is old; accordingly, kindly replace it by a more recent one (last five years of publication).
39. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, line 290: Kindly replace “is” by “was”.
40. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 7, lines 293-296: “However… system”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
41. Results and Discussion, 3.3. Essential oil extraction: Page 9, lines 311-312: “Although… [40]”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
42. Results and Discussion, 3.3. Essential oil extraction: Page 9, line 321: Kindly adjust as follow: “included”.
43. Results and Discussion, 3.3. Essential oil extraction: Page 9, lines 323-325: “All these… [42]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
44. Results and Discussion, 3.3. Essential oil extraction: Pages 9-10, lines 328-334: “For example… [46]”: Same recommendation as in the previous comment.
45. Results and Discussion, 3.3. Essential oil extraction: Page 10, lines 338-339: “Also… extraction”: Kindly reformulate this sentence in a more appropriate manner.
46. Results and Discussion, 3.3. Essential oil extraction: Page 11, lines 342-344: “As the metals… etc”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
47. Results and Discussion, 3.4. Biochar characterization: Page 11, lines 356-360: “The endothermic… [49]”: Kindly adopt the past verbal tense form for these sentences.
48. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 12, lines 369-372: “The hysteresis… micropores”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
49. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 12, line 381: Kindly adjust as follow: “presented”.
50. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 12, line 386: Kindly replace “is” by “was”.
51. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 12, lines 389-390: “Then… nature”: Kindly adopt the past verbal tense form for this sentence.
52. Results and Discussion, 3.4. Biochar characterization, 3.4.2. Thermal characterization (Atd-Tg): Pages 12-13, lines 393-402: “The DTA… precursor”: Same recommendation as in the previous comment.
53. Results and Discussion, 3.4. Biochar characterization, 3.4.3. Structural characterization, 3.4.3.1. Infrared spectroscopy: Page 13, lines 408-412: “While… [53]”: Same recommendation as in the previous two comments.
54. Results and Discussion, 3.4. Biochar characterization, 3.4.3. Structural characterization, 3.4.3.2. Raman spectroscopy: Page 15, lines 425-427: “The D band… [54]”: Same recommendation as in the previous comments. Moreover, kindly reformulate this sentence in a more appropriate manner.
55. Results and Discussion, 3.4. Biochar characterization, 3.4.3. Structural characterization, 3.4.3.2. Raman spectroscopy: Page 15, lines 430-432: “After… the sample”: Kindly adopt the past verbal tense form for these sentences.
56. Results and Discussion, 3.4. Biochar characterization, 3.4.3. Structural characterization, 3.4.3.3. Chemical characterization (elemental): Page 15, lines 434-439: “The biochar… 13.4%O”: Same recommendation as in the previous comment.
57. Results and Discussion, 3.5. Application of biochar in electrodes: Page 15, lines 445-448: “Although… content”: Same recommendation as in the previous two comments. Moreover, the reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
58. Results and Discussion, 3.5. Application of biochar in electrodes: Page 15, lines 448-450: “It should… role”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
59. Results and Discussion, 3.5. Application of biochar in electrodes: Page 15, line 453: Kindly adjust as follow: “In this study”.
60. Results and Discussion, 3.5. Application of biochar in electrodes: Page 15, line 454: Kindly adjust as follow: “possessed”.

Comments on the Quality of English Language

The manuscript needs major linguistic adjustments; accordingly, I invite the authors to pass their manuscript to a native English speaker for editing and revision. Most needed adjustments are highlighted in “Minor comments” section within the attached report.

Author Response

Open Review 4

Major comments

Coment 1: The manuscript needs major linguistic adjustments; accordingly, I invite the authors to pass their manuscript to a native English speaker for editing and revision. Most needed adjustments are highlighted in “Minor comments” section.

Response 1: Following the reviewer's advice, the manuscript has undergone a comprehensive linguistic revision. We have employed professional editing tools and conducted a peer-review check with colleagues fluent in English to ensure idiomatic accuracy and formal academic tone. Some sections have been rewritten to eliminate ambiguity and enhance readability.

Coment 2: Numerous statements show old sources (references) that should be replaced by more recent ones (last five years of publication).

Response 2: We appreciate the reviewer's observation on the actuality of the references. We understand the importance of including recent literature in this dynamic field. Following their recommendation, we have incorporated 14 new references from the period 2021-2025 in the Introduction and Discussion sections that reinforce our findings with state-of-the-art phytoremediation and energy storage data, balancing the historical basis with the current state of the art. But some citations from 2015 or earlier have been maintained because both research and conclusions remain relevant, and no evidence has been reported to refute their results.

Coment 3 (Abstract): The Abstract section can be reformulated in a more appropriate manner.

Response 3 (Abstract): The Abstract has been rewritten.

Coment 4 Materials and Methods, 2.2. Measurement of metal content): Kindly describe briefly the adopted methodology

Response 4:  We appreciate the reviewer’s suggestion. We have expanded the methodology section to include specific details regarding the sample preparation process (L. 212-216).

Coment 5: Results and Discussion, 3.1. Morphometry: The scientific analysis of the findings should be well improved. Percentages of variation (improvements/decreases)should be highlighted.

Response 5:  Thank you very much. Following the recommendations of the reviewer, section 3.1 has been rewritten to include the percentages of variation.

Coment 6: Results and Discussion, 3.2. Study of heavy metal(loid)s content: The outline of significance differences through statistical letters in tables should be performed. Also, the scientific analysis of the findings should be adjusted accordingly; percentages of variation (improvements/decreases)should be highlighted.

Response 6: Thank you very much. Following the recommendations of the reviewer, section 3.2 has been rewritten to include the percentages of variation.

Coment 7: Results and Discussion, 3.3. Essential oil extraction: Page 11, lines 348-354: More recent studies (last five years of publication if possible) are needed to discuss the obtained findings and a better performance of the discussion is urged.

Respose 7: Bibliography has been updated.

Coment 8: Conclusions: Amore concise Conclusions section shall be provided in a way that much better summarize the findings of the study. Authors shall also suggest further related research being based on the raised assumptions.

Response 8: Conclusions have been modified.

Minor comments

Response: The text has been revised, the English style has been revised, and some old references have been removed and others from the last 5 years have been incorporated (approximately 14 new references from the period 2021-2025). But some citations from 2015 or earlier have been maintained because both research and conclusions remain relevant, and no evidence has been reported to refute their results.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Circular Management of Lavandula stoechas L. Post Phytoremediation of Contaminated Soils. From Essential Oil to Potential Biochar for Supercapacitors

 

Comment-1 (Re-comment 5): As the material shows higher proportion of microporous than meso-porous, the BJH plot starting point from 3nm suggests that the instrument may not support accurate measurement of micropores. It would try better to use another BET surface analyser or repeat with same instrument (Micromeritics Tristar 3000) by changing the initial point from zero for the BJH measurement, so that the BJH plot can include the initial region below 2 nm. Therefore, author should repeat BET-BJH analysis.

Comment-2 In section 2.5.1 Characterization and Instrumentation (L-276), the term nitrogen adsorption is incorrect. Author should revise it to “nitrogen adsorption-desorption”. Additionally, instead of numbering it as 2.5.1, it would be better to revise the numbering to 2.6.

 

All other comments have been properly addressed, and the manuscript is well written. Only this minor correction is required.

Author Response

Review 1

Comment-1 (Re-comment 5): As the material shows higher proportion of microporous than meso-porous, the BJH plot starting point from 3nm suggests that the instrument may not support accurate measurement of micropores. It would try better to use another BET surface analyser or repeat with same instrument (Micromeritics Tristar 3000) by changing the initial point from zero for the BJH measurement, so that the BJH plot can include the initial region below 2 nm. Therefore, author should repeat BET-BJH analysis.

Response 1: We appreciate the reviewer's comment. However, we believe that repeating the analysis under the suggested conditions would not provide physically valid data due to the technical limitations of the equipment and the theoretical fundament of the BJH model.

One of the instrumental limitations is the pressure range of the equipment used (Micromeritics Tristar 3000), which operates with a mechanical vacuum system (no turbomolecular pumps). This limits the possibility to reach and stabilize pressures below 10⁻², while micropore analysis (pores<2 nm) requires isotherm measurement at extremely low relative pressures (P/P₀ between 10⁻⁷ and 10⁻⁵). Therefore, even if the analysis is repeated, the equipment has not the necessary sensitivity to obtain reliable experimental data points in the ultramicropore (<0.7 nm) or supermicropore (0.7–2 nm) regions.

On the other hand, the Barrett-Joyner-Halenda (BJH) method is based on the Kelvin equation, and this equation loses physical validity below 2 nm because the micropore filling mechanism does not occur through capillary condensation (2-50 nm) but rather through volumetric micropore filling. This method also exhibits mathematical instability at relative pressures P/P₀ below 0.3. Attempting to extrapolate this model below 2 nm would result in an erroneous and physically meaningless pore size distribution.

However, although the equipment cannot quantify the size of the micropores, it does detect them and this is evidenced in this work by the marked difference between the BET area (393.7m²/g), which includes microporosity, and the BJH area (234.9 m²/g), limited to mesopores.

Comment-2: In section 2.5.1 Characterization and Instrumentation (L-276), the term nitrogen adsorption is incorrect. Author should revise it to “nitrogen adsorption-desorption”. Additionally, instead of numbering it as 2.5.1, it would be better to revise the numbering to 2.6.

Response 2: Thank you for your feedback. The suggested changes have been corrected and marked in blue.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have addressed all the points. However, please italicize the scientific name mentioned in the title and in line 14 of Abstract.

Author Response

Review 2

Comment-1: The authors have addressed all the points. However, please italicize the scientific name mentioned in the title and in line 14 of Abstract

Response 1: We appreciate your observation. We sorry about the scientific names. Italics have been applied in accordance with the reviewer's suggestions.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have revised the manuscript in response to all the comments, and the article can now be published.

Author Response

No comments were made by this reviwer.

Reviewer 4 Report

Comments and Suggestions for Authors

Comments to the Author:

Title: Circular Management of Lavandula stoechas L. Post- Phytoremediation of Contaminated Soils from Essential Oil to Potential Biochar for Supercapacitors

 

Overview and general recommendation:

Authors have made significant improvements to their manuscript and are well thanked for that. However, still major and other minor adjustments are still required at this stage.

My comments and queries for authors are detailed below in “Major comments” and “Minor comments” sections.

 

Major comments:

1. The manuscript needs linguistic adjustments. Most needed adjustments are highlighted in “Minor comments” section.
2. Numerous statements show old sources (references) that should be replaced by more recent ones (last five years of publication).
3. Results and Discussion, 3.2. Study of heavy metal(loid)s content: The outline of significance differences through statistical letters in tables should be performed.
4. Results and Discussion, 3.3. Essential oil extraction: More recent studies are needed to discuss the obtained findings and a better performance of the discussion is urged.

 

Minor comments:

1. Abstract: Page 1, line 14: Kindly write the Latin name in Italic form.
2. Abstract: Page 1, line 17: Kindly adjust as follow: “confirmed”.
3. Abstract: Page 1, line 19: Kindly replace “By” by “Via”.
4. Abstract: Page 1, line 23: Kindly replace “is” by “can be”.
5. Abstract: Page 1, line 26: Kindly adjust as follow: “demonstrated”.
6. Introduction: Page 1, lines 32-34: “Mining… [1]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
7. Introduction: Pages 1-2, lines 40-43: “Although… tissues”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
8. Introduction: Page 2, lines 53-54: “It blooms… [13]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
9. Introduction: Page 2, lines 61-64: “Several… [15,16]”: Same recommendation as in the previous comment regarding reference number 16.
10. Introduction: Page 2, line 68: Reference number 20 is incomplete in the list of references; accordingly, kindly adjust it.
11. Introduction: Page 2, line 74: References numbers 24 and 25 are old; accordingly, kindly replace them by more recent ones (last five years of publication).
12. Introduction: Page 2, lines 80-82: “However… [27]”: Same recommendation as in the previous comment.
13. Introduction: Page 2, line 84: Kindly write the Latin name in Italic form.
14. Introduction: Page 2, line 87: Kindly replace “But” by “However”.
15. Introduction: Page 3, line 114: Kindly adjust as follow: “reduce”.
16. Materials and Methods, 2.1. Phytoremediation experiment, 2.1.1. Experimental design: Page 4, line 155: Kindly adjust as follow: “non-linear”.
17. Materials and Methods, 2.4. Statistical analysis: Page 6, line 252: Kindly adjust as follow: “non-parametric”.
18. Results and Discussion, 3.1. Morphometry: Page 8, line 291: Kindly adjust as follow: “inhibited”.
19. Results and Discussion, 3.1. Morphometry: Page 8, lines 304-305: Kindly write the Latin name in Italic form.
20. Results and Discussion, 3.1. Morphometry: Page 8, line 308: Kindly adjust as follow: “reported”.
21. Results and Discussion, 3.1. Morphometry: Page 8, line 309: Kindly adjust as follow: “the present results”.
22. Results and Discussion, 3.1. Morphometry: Page 8, line 310: Kindly write the Latin name in Italic form.
23. Results and Discussion, 3.1. Morphometry: Page 8, line 315: Kindly adjust as follow: “reached”.
24. Results and Discussion, 3.1. Morphometry: Page 8, line 316: Kindly adjust as follow: “varied”.
25. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 8, line 332: Kindly adjust as follow: “In this study”.
26. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 8, line 332: Kindly adjust as follow: “were significantly”.
27. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 8, line 336: Kindly write the Latin name in Italic form.
28. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 9, line 340: Same recommendation as in the previous comment.
29. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 9, line 352: Kindly adjust as follow: “in this study”.
30. Results and Discussion, 3.2. Study of heavy metal(loid)s content: Page 9, line 359: Kindly adjust as follow: “the present results”.
31. Results and Discussion, 3.3. Essential oil extraction: Page 10, line 377: Kindly write the Latin name in Italic form.
32. Results and Discussion, 3.3. Essential oil extraction: Page 11, line 396: Kindly replace “are” by “were”.
33. Results and Discussion, 3.3. Essential oil extraction: Page 11, lines 397-401: “This absence… [44]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
34. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 14, lines 439-443: References numbers 49 and 50 are incomplete in the list of references; accordingly, kindly update them.
35. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 14, lines 458-460: “On the other… [53]”: The reference used for this statement is old; accordingly, kindly replace it by a more recent one (last five years of publication).
36. Results and Discussion, 3.4. Biochar characterization, 3.4.1. textural characterization of biochar (N₂adsorption): Page 14, line 461: Kindly adjust as follow: “balanced”.
37. Results and Discussion, 3.4. Biochar characterization, 3.4.3. Structural characterization, 3.4.3.2. Raman spectroscopy: Page 17, lines 499-501: “The D band… [58]”: The sentence is badly written in standard English; accordingly, kindly reformulate it.
38. Results and Discussion, 3.5. Application of biochar in electrodes: Page 19, line 535: Kindly adjust as follow: “showed”.
39. Results and Discussion, 3.5. Application of biochar in electrodes: Page 19, line 537: Kindly replace “has” by “had”.
40. Results and Discussion, 3.5. Application of biochar in electrodes: Page 19, lines 535-540: “Although… role”:
41. The references used for these statements are old; accordingly, kindly replace them by more recent ones (last five years of publication). Moreover, the references attributed to these statements are incomplete in the list of references.
42. Conclusions: Page 19, line 565: Kindly adjust as follow: “demonstrated”.
43. Conclusions: Page 19, line 571: Kindly adjust as follow: “reached” and replace “has” by “had”.

Comments on the Quality of English Language

The manuscript needs linguistic adjustments. Most needed adjustments are highlighted in “Minor comments” section within the attached report.

Author Response

Review 4

Major and Minor comments:

Comment-1: The manuscript needs linguistic adjustments. Most needed adjustments are highlighted in “Minor comments” section.

Response 1: We appreciate the reviewer’s feedback. We have implemented all the linguistic adjustments suggested in the “Minor comments” section (in blue). Coment nº7 (lines 40-44). Coment nº 37 (lines 510-514).

Comment-2: Numerous statements show old sources (references) that should be replaced by more recent ones (last five years of publication).

Response 2: Thank you for this constructive comment. Bibliography has been updated in order to prioritize new research. We have substituted old references by new ones of the last five years (in blue).

Comment-3: Results and Discussion, 3.2. Study of heavy metal(loid)s content: The outline of significance differences through statistical letters in tables should be performed.

Response 3: Following the reviewer's suggestion, we have updated Table 2 to include the significant differences. We performed pairwise comparisons using the Mann-Whitney U test, and these differences are now indicated with statistical letters. Groups sharing the same letter do not differ significantly (p > 0.05).

Comment-4: Results and Discussion, 3.3. Essential oil extraction: More recent studies are needed to discuss the obtained findings and a better performance of the discussion is urged.

Response 4: Following the reviewer's recommendation, the discussion in section 3.3 has been improved. We have integrated recent studies that allow a stronger interpretation of the results, discussing some critical factors such as the plant's ability to manage metabolic stress and the toxicological safety of distillation products according to the current European Pharmacopoeia (Ph.Eur), which were not sufficiently addressed in the previous version. These changes can be found on lines 377-380, 393-396, 406-407, 414-417, and 420-423.

 

Author Response File: Author Response.docx

Round 3

Reviewer 4 Report

Comments and Suggestions for Authors

Comments to the Author:

Title: Circular Management of Lavandula stoechas L. Post- Phytoremediation of Contaminated Soils from Essential Oil to Potential Biochar for Supercapacitors

 

Overview and general recommendation:

Authors have made significant improvements to their manuscript and are well thanked for that. Although minor adjustments are needed, they can be made during the pre-proof stage.

Therefore, based on the overall evaluation of the manuscript, I find it well suitable for publication in current form.

My comments and queries for authors are detailed below in “Minor comments” section.

 

Minor comments:

1. Results and Discussion, 3.3. Essential oil extraction: Page 10, line 378: Kindly adjust as follow: “suggested”.
2. Results and Discussion, 3.3. Essential oil extraction: Page 12, line 406: Kindly adjust as follow: “showed”.
3. Results and Discussion, 3.3. Essential oil extraction: Page 12, line 415: The reference used in incomplete in the list of references; accordingly, kindly update it.
4. Results and Discussion, 3.5. Application of biochar in electrodes: Page 19, lines 548-553: “Although… role”: Same recommendation as in the previous comment.