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  • Muhammad Alamzeb 1,*,
  • Madiha Tullah 1 and
  • Mohamad Nasir Mohamad Ibrahim 6,*
  • et al.

Reviewer 1: Anonymous Reviewer 2: Sapana Jadoun Reviewer 3: Mohamed Ashour Fikry

Round 1

Reviewer 1 Report

In this work, the authors used native (GP) and washed garlic peel (WGP) as adsorbates to remove Eriochrome Black T (EBT) from simulated water samples. It is known that EBT is used for the dyeing of wool, nylon and silk and that long-term contact with EBT can cause irritation of the skin, eye, mucosal tissues and respiratory organs. They used FTIR, SEM, BET and BJH analysis to reveal the surface and structural characterization of native and washed GP. Several parameters such as pH, temperature, contact time, adsorbent dose and the initial dye concentration were selected to determine the best adsorption conditions. Freundlich and Langmuir's isotherms were employed for the equilibrium data. The adsorption kinetics was investigated by Pseudo-first and second-order models. They presented a perfect explanation of the equilibrium data using the Langmuir isotherm and pseudo-second-order model. The results of ΔG°, ΔH°, ΔS° studies indicated that adsorption of EBT onto GP and WGP was a favorable, spontaneous and physical process. GP and WGP give the maximum dye removal yield at pH 2. They demonstrated that the maximum dye removal yield and maximum adsorption capacities of GP are 96% and 99.5 mg/g and that the maximum dye removal yield and maximum adsorption capacities of WGP are 82 % and 89.4 mg/g. Finally, they concluded that garlic peel can be used as a cheaper and more efficient material for the adsorptive removal of EBT from contaminated water samples.

 

The FT-IR spectrum in Figure 1 and SEM images in Figure 2 are not enough clear. Please revise Figure 1 and Figure 2 using high-definition images. Moreover, please give the data about the change in the surface area, pore volume and pore size of the other materials when they were employed to adsorb the dyes or pollutants. Maybe, the adsorption behavior of some materials published in the previous work is similar to the garlic peel. Please cite the relevant references.

Author Response

Reviewer 1:

The FT-IR spectrum in Figure 1 and SEM images in Figure 2 are not enough clear. Please revise Figure 1 and Figure 2 using high-definition images.

Answer: The resolutions of Figure 1 and 2 have been improved. We hope that they are okay now.

 Moreover, please give the data about the change in the surface area, pore volume and pore size of the other materials when they were employed to adsorb the dyes or pollutants. Maybe, the adsorption behavior of some materials published in the previous work is similar to the garlic peel. Please cite the relevant references.

Answer: We have managed to find only one publication of such kind and we have incorporated their findings in the revised manuscript.

Reviewer 2 Report

Please see my comments for the manuscript "Kinetic, thermodynamic and adsorption isotherm studies of detoxification of Eriochrome Black T dye from wastewater by native and washed garlic peel" for possible publication in water.

1. Line 16 in the abstract, "is not desirable" is not a good word to express such pollution because it's obvious that nobody desires pollution. Replace this

2.1st paragraph of the introduction is too long. It should be divided into two parts 1st about dye pollution and 2nd about techniques to remove it.

3. TGA should be performed to check the stability of materials

4. UV-Visible spectra should be done to see the absorbance peak related to the material.

5. Please discuss about desorption studies in the discussion.

Author Response

Reviewer 2

  1. Line 16 in the abstract, "is not desirable" is not a good word to express such pollution because it's obvious that nobody desires pollution. Replace this

Answer: The suggested change has been made

2.1st paragraph of the introduction is too long. It should be divided into two parts 1st about dye pollution and 2nd about techniques to remove it.

Answer: The change has been made in the revised manuscript

  1. TGA should be performed to check the stability of materials

Answer: Thank you very much for a very valid point. The TGA analysis of GP has been reported from literature in the revised manuscript.

Actually, we used the plant-based adsorbent in the temperature range of 20 to 50 ℃ and during the course of our literature search we seldom saw any TGA analysis performed for plants-based adsorbents, and hence we did not perform TGA analysis of our samples. Unfortunately, we do not have those samples with us now so we are unable to perform their TGA. We request to accept this manuscript without TGA, we will definitely perform TGA for all of our samples now and we will provide TGA data in all our upcoming manuscripts.  

  1. UV-Visible spectra should be done to see the absorbance peak related to the material.

Answer: The UV-visible spectra in relation with adsorbent has been provided in the revised manuscript.

  1. Please discuss about desorption studies in the discussion.

Answer: The desorption studies have been added in the discussion of the revised manuscript.

Reviewer 3 Report

The manuscript (water- 2025985): Kinetic, thermodynamic and adsorption isotherm studies of detoxification of Eriochrome Black T dye from wastewater by native and washed garlic peel.

 This result is very high and I think this material is a very promising biological material to use in bioremediation. But the study needs some improvements before going to accept this article:

 

1.    The introduction is poor and did not introduce the point of study well. Authors may use the following refs:  https://doi.org/10.3390/ma14164446 ; https://doi.org/10.3390/polym14071375 ;  https://doi.org/10.3390/su13137077

2.    Authors should explain the novelty of this work at the end of the introduction (before the aim of the work).

3.   Replace Fig 2 and 3 with high-resolution ones

4.   In the conclusion, add more results and specifications of GP and WGP

Author Response

Reviewer 3

  1. The introduction is poor and did not introduce the point of study well. Authors may use the following refs: https://doi.org/10.3390/ma14164446 ; https://doi.org/10.3390/polym14071375 ;  https://doi.org/10.3390/su13137077

Answer: Thank you very much for your valuable suggestion. The suggested papers were downloaded and studied, and introduction section has been improved and the suggested papers have been cited. We hope it will be to your liking now.

  1. Authors should explain the novelty of this work at the end of the introduction (before the aim of the work).

Answer: The suggested improvement has been made in the revised manuscript.

 

  1.  Replace Fig 2 and 3 with high-resolution ones

Answer: The resolutions of Figure 2 and 3 have been improved in the revised manuscript.

  1.  In the conclusion, add more results and specifications of GP and WGP

Answer: The missing data has been provided in the conclusion section of the revised manuscript.

Round 2

Reviewer 1 Report

I have no questions about this manuscript any more.

Reviewer 2 Report

The manuscript can be accepted in its present form as the authors have resolved the maximum comments.