Efficient Dye Removal from Real Textile Wastewater Using Orange Seed Powder as Suitable Bio-Adsorbent and Membrane Technology

Round 1

Reviewer 1 Report

This manuscript presents an study on the adsorptive capacity of fat-free orange seeds powder for colour removal of a real textile wastewater. The adsorption experiments were performed in batch, and then the bio-adsorbent was removed by filtration using inorganic membranes.   The novelty of the paper is mainly on the evaluation of a bio-adsorbent using a real wastewater. Issue of the manuscript is interest and has a good design in adsorption tests, however, there are some statements which does not support the topic and even not rigorous. I consider the manuscript can be accepted after the authors have addressed the following issues:  

 

General

English: There are some grammar and spelling errors. Some sentences are hard to understand. Thus, the language should be improved by an English native teacher, a teacher with good English or a language editing organization skill to eliminate the errors and enhance the readability of the manuscript.

 

Introduction

•             Introduction needs a thorough revision and improvement (just to mention some issues… see year in line 46, revise abbreviations not previously defined, redaction in lines 69-74)

Results and discussion

•             check line 133, 137. There´s no reaction in the system.

•             Revise eq. (3), h is missing.

•             It is not clear if wastewater comes from alpaca wool or cotton processing. This should be stated since wastewater characteristics are different in nature. Please inform which kind of dyes is present in the wastewater.

•             Line 200. Please rewrite: “Although, the bio-adsorbent was evaluated for pure dye removal [32,33], for real textile wastewater that is a complex system (organic compounds, mixture of dyes), this has not been reported, yet and its mechanism is unknow.” It´s not clear. To which mechanism do the authors refer?

•             Please revise or remove the following phrase:  “Moreover, the presence of humic acid in the  wastewater could also help adsorption; therefore, more studies are required.” This seems not connected to wastewater characterization or the experimental results presented

•             Lines from 234 to 244, please revise and rewrite. It´s not clear.

•             Lines from 272 to 275, a comparison between experiments using different dyes and adsorbents at different operating conditions is made, Which is the temperature at optimized operating conditions at ref. (35)? It seems this comparison is not helpful since it does not demonstrate the superiority or not of one adsorbent over the other.

•             Please revise lines 325-327

•             A blank experiment using distilled water should be conducted and its result included in the discussion section. This could explain trends reported in Table 5.  

•               Figure 5 includes a plot and a table. It is not clear and has low quality. Please present a better  figure or the table, not both. They provide the same information.

Conclusion

•             This section should be revised and rewritten to highlight main conclusions.

 

 

Author Response

General comment: This manuscript presents a study on the adsorptive capacity of fat-free orange seeds powder for colour removal of a real textile wastewater. The adsorption experiments were performed in batch, and then the bio-adsorbent was removed by filtration using inorganic membranes.   The novelty of the paper is mainly on the evaluation of a bio-adsorbent using a real wastewater. Issue of the manuscript is interest and has a good design in adsorption tests, however, there are some statements which does not support the topic and even not rigorous. I consider the manuscript can be accepted after the authors have addressed the following issues:

Answer: Thank you for your comments, suggestions, and criticism which are fundamental to improve the quality of this manuscript. The new version of the manuscript was carefully revised, and all the comments were considered.

Comment 1: English: There are some grammar and spelling errors. Some sentences are hard to understand. Thus, the language should be improved by an English native teacher, a teacher with good English or a language editing organization skill to eliminate the errors and enhance the readability of the manuscript.

Answers: Thank you for your suggestion. The new version of the manuscript was revised carefully.

Comment 2: Introduction needs a thorough revision and improvement (just to mention some issues… see year in line 46, revise abbreviations not previously defined, redaction in lines 69-74).

Answer: Thank you for your comment. This section, abbreviations, and redaction were improved and corrected.

Comment 3: check line 133, 137. There´s no reaction in the system.

Answer: Thank you for your comment. This section was corrected.

Comment 4: Revise eq. (3), h is missing.

Answer: Thank you for your comment. In Eq. (3) the letter h is not part of the equation, h is only the abbreviation of the  expression in Eq. (3).

Comment 5: t is not clear if wastewater comes from alpaca wool or cotton processing. This should be stated since wastewater characteristics are different in nature. Please inform which kind of dyes is present in the wastewater.

Answer: Thank you for your comment. The textile company mainly works with alpaca wool, but they also sometimes work with cotton as stated by the company staff. Therefore, it is difficult to know exactly the type of dyes present in wastewater. However, we confirm the presence of Lanaset Red-G as one of the dyes used for alpaca wool, as previously reported by M.A.D. Flores Alarcón et al (2022).

Reference:

• Alarcón, M. A. F., Jarro, R. Y. A., Ahmed, M. A., Bustos, K. A. G., Tanaka, D. A. P., & Hilares, R. T. (2022). Intensification of Red-G dye degradation used in the dyeing of alpaca wool by advanced oxidation processes assisted by hydrodynamic cavitation. Ultrasonics Sonochemistry, 89, 106144.

Comment 6: Line 200. Please rewrite: “Although, the bio-adsorbent was evaluated for pure dye removal [32,33], for real textile wastewater that is a complex system (organic compounds, mixture of dyes), this has not been reported, yet and its mechanism is unknow.” It´s not clear. To which mechanism do the authors refer?

Answer: Thank you for your comment. This section was rewritten in the new version of the manuscript.  

Comment 7: Please revise or remove the following phrase: “Moreover, the presence of humic acid in the wastewater could also help adsorption; therefore, more studies are required.” This seems not connected to wastewater characterization or the experimental results presented.

Answer: Thank you for your suggestion. The phrase indicated was removed in the new version of the manuscript as suggested.

Comment 8: Lines from 234 to 244, please revise and rewrite. It´s not clear.

Answer: This section was revised and rewritten as suggested.

Comment 9: Lines from 272 to 275, a comparison between experiments using different dyes and adsorbents at different operating conditions is made, which is the temperature at optimized operating conditions at ref. (35)? It seems this comparison is not helpful since it does not demonstrate the superiority or not of one adsorbent over the other.

Answer: Thank you for your comment. Effectively, the comparison of the removal efficiency (%) to reference [35] is not correct, once the material, process conditions and dyes are not the same. Therefore, reference [35] was used only as comparative aiming to show the potential of orange seeds as bio-adsorbent. This section in the new version of the manuscript was rewritten. 

Comment 10: Please revise lines 325-327.

Answer: Thank you for your comment. This section was revised in the new version of the manuscript.

Comment 11:  A blank experiment using distilled water should be conducted and its result included in the discussion section. This could explain trends reported in Table 5. 

Answer: Thank you for your comment. It is an interesting view point to evaluate the contribution of bio-adsorbent residues in parameters of treated wastewater after filtration. This strategy will be considered in our future works.  However, for the quantification experiments. a blank with water or a calibration line using water were performed.  In addition to this, membrane permeation was carried out with water in order to warrant that the membrane system is working properly before the test with waste water 

Comment 12: Figure 5 includes a plot and a table. It is not clear and has low quality. Please present a better figure or the table, not both. They provide the same information.

Answer: Thank you for your suggestion. The Figure 5 was improved as suggested.

Comment 13: This section should be revised and rewritten to highlight main conclusions.

Answer: Thank you for your suggestion. This section was improved in the new version of the manuscript.

Reviewer 2 Report

In this work the authors investigated a orange seed powder as bioadsorbent for dye removal from industrial waste waters. This is an interesting paper but confusingly written and without scientific sound. Major revision is required before publication.

IN GENERAL: In this work, the application of the material as an adsorbent of dye and wastewater was examined, it was shown that this material is very efficient, but we do not get any information about the material and the mechanisms of interaction with the dye. Scientific works should first be based on a detailed characterization of the examined material, and based on its structure, it should be seen whether they are suitable for some application and which one. If they are used as dye adsorbents, first a series of experiments should be done in synthetic solutions of the investigated pollutant, and scientific knowledge such as kinetics, interaction mechanisms and others will be obtained. Only after all this knowledge is the material applied in a complex system such as waste water. If the authors have already published such works, they should refer to them and cite them in this manuscript.

Abstract  is not convincing and correctly written. The abstract should be an objective representation of the article and must highlight the purpose of the study; it should describe briefly the main methods  applied, summarize the article's main findings; and indicate the main conclusions.

The authors should emphasize the novelty in Introduction part. The main methods used in the work should be stated.

The authors state that orange seeds were obtained at local market. Have the material been bought or collected at local market?

Whether experiments were done in multiple replicates?

L 175-176: Moreover, currently the use for dye
removal from textile wastewater has not yet been report - is that statement correct?

In the materials and methods section, it was not stated that ANOVA was used

 

Author Response

General comment: In this work the authors investigated an orange seed powder as bio-adsorbent for dye removal from industrial waste waters. This is an interesting paper but confusingly written and without scientific sound. Major revision is required before publication.

Answer: Thank you for your comments, suggestions, and criticism, which were fundamental to improve the quality of this manuscript. The new version of the manuscript was carefully revised, and all the comments were considered.

Comment 1: In this work, the application of the material as an adsorbent of dye and wastewater was examined, it was shown that this material is very efficient, but we do not get any information about the material and the mechanisms of interaction with the dye. Scientific works should first be based on a detailed characterization of the examined material, and based on its structure, it should be seen whether they are suitable for some application and which one. If they are used as dye adsorbents, first a series of experiments should be done in synthetic solutions of the investigated pollutant, and scientific knowledge such as kinetics, interaction mechanisms and others will be obtained. Only after all this knowledge is the material applied in a complex system such as waste water. If the authors have already published such works, they should refer to them and cite them in this manuscript.

Answer: Thank you for your comment. Indeed, in the development of new materials, the initial characterization using dyes or pure compounds is essential; however, many studies remain at that level. Effectively, the use of pure compounds allows to understand the mechanism; but they are hardly applicable to complex systems such as real effluents where it is impossible to identify all the components and the interactions between them and their interference during the adsorption and analysis. In our group we also do basic studies on thermodynamics and kinetics of specific dyes. Since our purpose was to solve the problem of contamination of a specific company, we decided to use a real sample in the near future directly, the complete study using different types of dyes.

Comment 2: Abstract is not convincing and correctly written. The abstract should be an objective representation of the article and must highlight the purpose of the study; it should describe briefly the main methods applied, summarize the article's main findings; and indicate the main conclusions.

Answer: Thank you for your comment. The abstract of the manuscript was improved as suggested.

Comment 3: The authors should emphasize the novelty in Introduction part. The main methods used in the work should be stated.

Answer: Thank you for your comment. The introduction section was emphasized as suggested.

Comment 4: The authors state that orange seeds were obtained at local market. Has the material been bought or collected at local market?

Answer: Thank you for your question. The material was collected in a local market, washed, dried and milled. 

Comment 5: Whether experiments were done in multiple replicates?

Answer: Thank you for your question. All the experiments were performed by triplicates, and the average was reported.

Comment 6: L 175-176: Moreover, currently the use for dye removal from textile wastewater has not yet been report - is that statement, correct?

Answer: Thank you for your comment. This section was improved.

Comment 7: In the materials and methods section, it was not stated that ANOVA was used

Answer: This information was included in the new version of the manuscript.  

 

Round 2

Reviewer 1 Report

The authors have properly addressed all of this reviewer´s comments.

Reviewer 2 Report

This Manuscript should be accepted