CO₂ Adsorption of Materials Synthesized from Clay Minerals: A Review

Round 1

Reviewer 1 Report

It is very hard to understand your points related to this MS. Maybe you can describe your motivation or objective more detailedly.

Does this MS can apply in any other cases? Or it is just suitable for these two cases.

Does this MS have any geological significance? or implication?  

Author Response

Reviewer 1

It is very hard to understand your points related to this MS. Maybe you can describe your motivation or objective more detailedly.

The aim of the present review is to evaluate the potential of the clay minerals to be used as adsorbent in CO₂ capture processes. These minerals can be considered as potential adsorbents to retain CO₂ due to their high availability throughout the planet and their low cost.

Thus, following the advice of the reviewer the authors have completed the last paragraph of the introduction section, indicating the aim of this review “Considering that the CO₂ capture is the most expensive step in the CCS process, it is necessary the development of inexpensive adsorbents to obtain economically and environmentally sustainable processes to be implanted on a larger scale. In this sense, clay minerals have emerged as alternative due to their excellent behavior in the fields of the adsorption and catalysis for many industrial applications [20]. This fact together with its high availability, stability make them potential adsorbents to be used in CO₂ capture processes. Taking into account these premises, the aim of this review is to carry out a detailed study of clay minerals as potential adsorbent to capture CO₂. In addition, this manuscript also evaluates the modification of clay minerals to increase CO₂ adsorption capacity as well as the modification of these clay minerals by incorporating amino groups to increase the chemical interaction between the absorbent and the molecules of CO₂.

Does this MS can apply in any other cases? Or it is just suitable for these two cases.

The modification of the clay minerals can be applied to several applications, mainly in the field of the adsorption and catalysts. The aim of this manuscript is only focused on their application for the CO₂ adsorption. In this sense, the modification with amine groups in carried out to increase the CO₂ adsorption capacity since the chemical interaction between CO₂ molecules and the adsorbent increases. This strategy is used for the CO₂ adsorption capacity; however, these clay minerals modified with amine species can also be used for adsorption of another molecules as dyes, pesticides or biomolecules.

Does this MS have any geological significance? or implication?

The surface of the Earth has a large proportion of clay minerals. These clay minerals are not harmful for the environment and humans. On the other hand, these clay minerals neither has geological significance

Also, I attach you the response of the reviewer in the next file.

Author Response File: Author Response.docx

Reviewer 2 Report

This review describes the synthesis and use of modified clays for CO2 capture applications. It covers grafting and coating with amine, chemical transformations of clay minerals, and CO2 sorption measurements. Differernt clay materials are described, and their CO2 sorption properties explained. Changes in CO2 sorption capacity are related to the chemical and structural modifications, and discussed for their potential use in carbon capture. This is an very interesting and timely review of the recent progress in this field.

Author Response

I attach you the response of the reviewer 2 in the following file

Author Response File: Author Response.docx

Reviewer 3 Report

In the present manuscript, authors provide a brief overview about the utilization of clay minerals and their derivatives for applications in CO2 capture. A few modifications are necessary before considering for final acceptance.

1. Language corrections are to be made throughout the manuscript. For example, the third sentence in the introduction part, “Among all processes generated in the combustion processes…..”. Similar discrepancies can be observed throughout the text.

2. There are a few schemes and figures provided in the manuscript. Are these made by the authors themselves? If not, proper references are to be provided.

3. The unit of temperature (°C) needs to be corrected throughout.

Author Response

I attach you the response of the reviewers in the following file

Author Response File: Author Response.docx