Uses of Nanoclays and Adsorbents for Dye Recovery: A Textile Industry Review

Round 1

Reviewer 1 Report

This manuscript focuses on textile wastewater recovery and summarizes the wastewater recovery capabilities of natural or synthetic nanoclays of different structures. Conceptual description of the manuscript is more scientific, the main information is clearly expressed and has a certain degree of distinction from the same type of review. However, the manuscript requires minor revisions before being published.

1. Compared with the word description, the number of pictures in the manuscript does not meet the requirements. The SEM image alone is not sufficient to support the described conclusions.
2. Author pays too much attention to the description of experimental conclusions and ignores reflection and future improvements. Connection between each part should be mentioned.
3. The author should pay more attention to the related literature in recent years rather than some older literature.

Author Response

We would like to thank the reviewer comments because it allow us to improve the quality of our manuscript. All the changes have been made using the automatic control for changes in word, and we justified them all point by point using blue type font as follows:

• Compared with the word description, the number of pictures in the manuscript does not meet the requirements. The SEM image alone is not sufficient to support the described conclusions.

The reviewer is right. Various figures have been added to better explain graphically and visually everything described in the text as you can see in the new figures 3,4,5,6,8,10,11.

• Author pays too much attention to the description of experimental conclusions and ignores reflection and future improvements. Connection between each part should be mentioned.

The reviewer is right and the following has been added as example:

On the other hand, when different authors talk about the desorption phase, they tend to give very ambiguous results, for example they give desorption values of between 20-40%, which is not very specific since the range of variation is very wide. For future lines, the quantification of many of the phases must be improved, for example the preparation of materials in which their adsorption capacity is improved by prior calcination, since it is not quantified to what degree the adsorption capacity improves due to previous loss of anions CO₃.

However, a textile application has not yet been studied in-depth, nor has the reuse of organic compounds after a desoption process been completey studied and described. Several factors must be considered and described, such as pH, time and temperatures, which recent works do not provide. The results obtained by these studies are ambiguous and need to be refuted. These studies demonstrate that the desorption process is viable as a promising future trend.

• The author should pay more attention to the related literature in recent years rather than some older literature.

The reviewer is right and the following has been added:

Chong, A. S.; Manan, M. A.; Idris, A. K. Readiness of Lignosulfonate Adsorption onto Montmorillonite. Colloids Surfaces A Physicochem. Eng. Asp. 2021, 628 (June), 127318. https://doi.org/10.1016/j.colsurfa.2021.127318.

Antúnez-García, J.; Galván, D. H.; Petranovskii, V.; Murrieta-Rico, F. N.; Yocupicio-Gaxiola, R. I.; Shelyapina, M. G.; Fuentes-Moyado, S. The Effect of Chemical Composition on the Properties of LTA Zeolite: A Theoretical Study. Comput. Mater. Sci. 2021, 196 (May). https://doi.org/10.1016/j.commatsci.2021.110557.

Lo, A. Y.; Taghipour, F. Review and Prospects of Microporous Zeolite Catalysts for CO2 Photoreduction. Appl. Mater. Today 2021, 23. https://doi.org/10.1016/j.apmt.2021.101042.

Probst, J.; Outram, J. G.; Couperthwaite, S. J.; Millar, G. J.; Kaparaju, P. Sustainable Ammonium Recovery from Wastewater: Improved Synthesis and Performance of Zeolite N Made from Kaolin. Microporous Mesoporous Mater. 2021, 316 (November 2020), 110918. https://doi.org/10.1016/j.micromeso.2021.110918.

Van Ranst, E.; Kips, P.; Mbogoni, J.; Mees, F.; Dumon, M.; Delvaux, B. Halloysite-Smectite Mixed-Layered Clay in Fluvio-Volcanic Soils at the Southern Foot of Mount Kilimanjaro, Tanzania. Geoderma 2020, 375 (May), 114527. https://doi.org/10.1016/j.geoderma.2020.114527.

Lazaratou, C. V.; Panagiotaras, D.; Panagopoulos, G.; Pospíšil, M.; Papoulis, D. Ca Treated Palygorskite and Halloysite Clay Minerals for Ferrous Iron (Fe+2) Removal from Water Systems. Environ. Technol. Innov. 2020, 19, 100961. https://doi.org/10.1016/j.eti.2020.100961.

Kenne Dedzo, G.; Rigolet, S.; Josien, L.; Ngameni, E.; Dzene, L. Functionalization of Synthetic Saponite: Identification of Grafting Sites and Application for Anions Sequestration. Appl. Surf. Sci. 2021, 567 (April), 150911. https://doi.org/10.1016/j.apsusc.2021.150911.

Fernández-González, M. V.; Carretero, M. I.; Martín-García, J. M.; Molinero-García, A.; Delgado, R. Peloids Prepared with Three Mineral-Medicinal Waters from Spas in Granada. Their Suitability for Use in Pelotherapy. Appl. Clay Sci. 2021, 202 (December 2020). https://doi.org/10.1016/j.clay.2020.105969.

Hamid, Y.; Tang, L.; Hussain, B.; Usman, M.; Liu, L.; Ulhassan, Z.; He, Z.; Yang, X. Sepiolite Clay: A Review of Its Applications to Immobilize Toxic Metals in Contaminated Soils and Its Implications in Soil–Plant System. Environ. Technol. Innov. 2021, 23, 101598. https://doi.org/10.1016/j.eti.2021.101598.

Hamid, Y.; Tang, L.; Hussain, B.; Usman, M.; Rehman Hashmi, M. L. ur; Bilal Khan, M.; Yang, X.; He, Z. Immobilization and Sorption of Cd and Pb in Contaminated Stagnic Anthrosols as Amended with Biochar and Manure Combined with Inorganic Additives. J. Environ. Manage. 2020, 257 (August 2019), 109999. https://doi.org/10.1016/j.jenvman.2019.109999.

Peng, L.; Chen, B.; Zhao, Y. Quantitative Characterization and Comparsion of Bentonite Microstructure by Small Angle X-Ray Scattering and Nitrogen Adsorption. Constr. Build. Mater. 2020, 262, 120863. https://doi.org/10.1016/j.conbuildmat.2020.120863.

Zhang, P.; Wang, J.; Jia, Y.; Li, W.; Tan, X.; Zhang, D.; Xu, S.; Zhang, P.; Wei, C.; Miao, S. Encapsulating Spinel Nancrystals in Laponite Cages and Applications in Molecular Oxidation of Cyclohexane. Appl. Clay Sci. 2019, 181 (May), 105226. https://doi.org/10.1016/j.clay.2019.105226.

Wang, Z.; Li, J.; Sun, Y.; Peng, J.; Wang, J.; Hao, Y.; Li, W.; Zhang, P.; Ning, W.; Miao, S. Laponite Elementary Sheets Assisted Fluorescence Resonance Energy Transfer: A Demonstration by Langmuir-Blodgett Technique. Dye. Pigment. 2021, 196 (June), 109800. https://doi.org/10.1016/j.dyepig.2021.109800.

Akil, J.; Ciotonea, C.; Siffert, S.; Royer, S.; Pirault-Roy, L.; Cousin, R.; Poupin, C. NO Reduction by CO under Oxidative Conditions over CoCuAl Mixed Oxides Derived from Hydrotalcite-like Compounds: Effect of Water. Catal. Today 2021, No. October 2020. https://doi.org/10.1016/j.cattod.2021.05.014.

Prasannan, A.; Udomsin, J.; Tsai, H.-C.; Wang, C.-F.; Lai, J.-Y. Robust Underwater Superoleophobic Membranes with Bio-Inspired Carrageenan/Laponite Multilayers for the Effective Removal of Emulsions, Metal Ions, and Organic Dyes from Wastewater. Chem. Eng. J. 2020, 391, 123585.

Author Response File: Author Response.docx

Reviewer 2 Report

This review may be of interest to specialists in the recovery of wastewater from textile industry. However, the text needs corrections.

The comments for the review are described below.

 

Specific comments.

1. Line 212. Clays have the property of swelling, but not inflatable.
2. Line 266, and further in the text.

The authors write: "Natural zeolite is a nanoclay mineral". But zeolites do not belong to clay minerals, and do not belong to nanoclays, respectively. Zeolites are used to filter water and wastewater, but they cannot be classified as nanoclays. This applies to line 266, and the text of other sections of the article and conclusions.

3. In one article it is necessary to use the same units of measurement for the same parameters. For example, lines 351 and 422 describe the CEC parameter with different units. When written this way, these parameters are difficult to compare.
4. Line 417. "Bentonite is a clayey aluminosilicate mineral." Bentonite is not a mineral, but a rock, dominated by the clay mineral smectite. Bentonite is used as nanoclay, but it is not a mineral.
5. Lines 449 and 456. Laponite is not a natural formation. Laponite is a synthetic element.
6. Line 538. "Another example of clay that allows dye desorption is zeolite." Zeolite is not clay. The note is written above.
7. Lines 565-567. Conclusions begin with the text: "This article describes some of the most widespread nanoclays in different hydrogel compounds of gelatin and clinoptilolite research that can be used for treating industrial wastewater (Table 2)."

The authors in this article have not previously described anything about "... different hydrogel compounds of gelatin and clinoptilolite ...".

This text may cause confusion while reading. 

8. Figure 4. Tubular halloysite is not visible in the figure. Better to use SEM image.

 

General comments to the article.

- The authors described specific adsorbents for wastewater recovery, but the set of parameters was chosen differently to describe each adsorbent. For some adsorbents there is a chemical formula, for others specific surface area and CEC. Why did the authors choose this description? There is enough information about them in the published literature.

- Not all adsorbents have images. Why did the authors use images obtained by different research methods (SEM, TEM)? These methods are designed to obtain different parameters of the material. In the article, it is necessary to show drawings for all adsorbents obtained by the same method. Better to use SEM images that can be interpreted more intuitively by a wide range of professionals.

- The article describes nanoclays and other adsorbents. Therefore, the title of the article better to be corrected, to reflect the content more appropriately. 

Author Response

Specific comments.

1. Line 212. Clays have the property of swelling, but not inflatable.

The reviewer is right so the appropriate modification has been made according to the reviewer's comments, sentence “Clays are divided into inflatable and non inflatable, and the former are called smectics” has been removed.

 

1. Line 266, and further in the text. The authors write: "Natural zeolite is a nanoclay mineral". But zeolites do not belong to clay minerals, and do not belong to nanoclays, respectively. Zeolites are used to filter water and wastewater, but they cannot be classified as nanoclays. This applies to line 266, and the text of other sections of the article and conclusions.

The appropriate modification has been made according to the reviewer's comments. As can be see: “Natural zeolite is a mineral widely used to treat wastewater”

1. In one article it is necessary to use the same units of measurement for the same parameters. For example, lines 351 100 mequiv./100 g and 422 40-130 cmol·kg⁻¹ describe the CEC (cation exchange capacity) parameter with different units. When written this way, these parameters are difficult to compare.

The reviewer is right. The denomination milli equivalent per 100 grams or meq / 100 g does not follow the current IUPAC standards, for this reason the units of cmol·kg⁻¹ have been choosen.

1. Line 417. "Bentonite is a clayey aluminosilicate mineral." Bentonite is not a mineral, but a rock, dominated by the clay mineral smectite. Bentonite is used as nanoclay, but it is not a mineral.

The appropriate modification has been made according to the reviewer's comments: “Bentonite (BTE) is an aluminosilicate formed by one octahedric aluminum oxide layer and two tetrahedric silicon oxide layers that results in a 1:2-type structure with chemical formula Al₂H₂Na₂O₁₃Si₄ [212],[213]”.

1. Lines 449 and 456. Laponite is not a natural formation. Laponite is a synthetic element.

The appropriate modification has been made according to the reviewer's comments: Synthetic Lap (Si₈[Mg_5.5Li_0.4H_4.0O₂₄]^0.7−Na_0.7⁺) is a 2D clay disc-shaped silicate whose dimensions are approximately 1 nm thick.

1. Line 538. "Another example of clay that allows dye desorption is zeolite." Zeolite is not clay.

The reviewer is right, and we have made the correction: Natural zeolite is a mineral widely used to treat wastewater. For the dehydrated zeolite chemical formula is [Al₁₂Si₁₂O₄₈]^12- [97].

1. Lines 565-567. Conclusions begin with the text: "This article describes some of the most widespread nanoclays in different hydrogel compounds of gelatin and clinoptilolite research that can be used for treating industrial wastewater (Table 2)."The authors in this article have not previously described anything about "... different hidrogel compounds of gelatin and clinoptilolite ...".This text may cause confusion while reading. 

The reviewer is right again and the appropriate modification has been made according to that reviewer's comments: “This article describes some of the most widespread nanoclays in different adsorbents research that can be used for treating industrial wastewater (Table 2).”  

1. Figure 4. Tubular halloysite is not visible in the figure. Better to use SEM image.

The new Figure 5 left has been added where the tubular shape of halloysite can be seen.

 General comments to the article.

- The authors described specific adsorbents for wastewater recovery, but the set of parameters was chosen differently to describe each adsorbent. For some adsorbents there is a chemical formula, for others specific surface area and CEC. Why did the authors choose this description? There is enough information about them in the published literature.

The reviewer is right again. For these reason the criteria have been unified so that all adsorbents and nanoclays have the SSA, chemical formula and CEC, in order to have a comparative vision between all of them. For example for MMT: The chemical composition for montmorillonite was composed of 80% of SiO₂, 13% of Al₂O₃, and 3% of Fe₂O₃ [78]_, and his specific surface area (SSA) is around 31.26 - 57.19 m²·g^-1 , in zeolite: For the dehydrated zeolite chemical formula is [Al₁₂Si₁₂O₄₈]^12- [97]. Their high specific surface areas is around 200–860 m² ·g⁻¹ and for all the adsorbents.

Not all adsorbents have images. Why did the authors use images obtained by different research methods (SEM, TEM)? These methods are designed to obtain different parameters of the material. In the article, it is necessary to show drawings for all adsorbents obtained by the same method. Better to use SEM images that can be interpreted more intuitively by a wide range of professionals.

Following the reviewer's advice we have used SEM images, although in some specific cases to complement we have also added some TEM.

The article describes nanoclays and other adsorbents. Therefore, the title of the article better to be corrected, to reflect the content more appropriately. 

We make a new proposal for the title taken into account the reviewer comment: “Nanoclays and adsorbents uses for dye recovery. A textile industry review.”

 

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Publish as it is .