Mechanistic Model and Optimization of the Diclofenac Degradation Kinetic for Ozonation Processes Intensification

Round 1

Reviewer 1 Report

This manuscript demonstrates the mechanistic model and optimization of diclofenac destruction kinetic for zonation processes enhancement. Three typical ozone-based processes, including ozonation alone (Oz), catalytic ozonation (COz), and photocatalytic ozonation (PCOz), were selected for estimating the rate constant of diclofenac destruction. Three models were developed to screen the optimal values for kinetics rate constant, accompanying with using Theil inequality coefficient as the criterion. Sufficient experiments were conducted to validate the accuracy of the developed models for the prediction of rate constant. This manuscript provides a deeper insight into the chemical and adsorption interaction as well as mass transfer, which are scarcely studied. It is a well-organized and interesting work. Therefore, I would recommend a moderate revision before its publication.

1. Title should be revised. Change “reaction” to “destruction” or “degradation”
2. There is no necessary to mark “(1)…(4)” in the abstract.
3. Line 17, the full name of first abbreviation of “Ha” should be added.
4. Some important works relating catalytic ozonation and photocatalytic ozonation should be added into the Introduction to support the authors’ perspectives. For instance, Environ. Sci. Technol. 2020, 54, 5931; Chemical Engineering Journal, 2021, 404, 127075; Applied Catalysis B: Environmental, 2019, 251, 66-75; Journal of Hazardous Materials, 2019, 367, 456-464.
5. Line 298, no Figure 7.b is available here.
6. Line 342, name of x-axis should be revised since it looks like a non-English word.
7. Line 530, “This review was supported” should be corrected.
8. Photocatalytic ozonation process is an attractive intensification approach for organic pollutant destruction. However, the most problem issue remain is the cost of this technique. The cost should include the set-up of special equipment and energy input. Perhaps, the authors can roughly calculate the electrical energy per order (EE/O, referred to Applied Catalysis B: Environmental, 2019, 251, 66-75) of ozonation, catalytic ozonation, and photocatalytic ozonation processes for comparison.
9. Can the catalytic ozonation model also be useful for other ozonation catalysts instead of TiO2, such as Fe-MOFs (Chemical Engineering Journal, 2021, 404, 127075; Applied Catalysis B: Environmental, 2019, 251, 66-75; Journal of Hazardous Materials, 2019, 367, 456-464.)?
10. Overall, this is a good work but the language usage should be polished.

Author Response

This manuscript demonstrates the mechanistic model and optimization of diclofenac destruction kinetic for zonation processes enhancement. Three typical ozone-based processes, including ozonation alone (Oz), catalytic ozonation (COz), and photocatalytic ozonation (PCOz), were selected for estimating the rate constant of diclofenac destruction. Three models were developed to screen the optimal values for kinetics rate constant, accompanying with using Theil inequality coefficient as the criterion. Sufficient experiments were conducted to validate the accuracy of the developed models for the prediction of rate constant. This manuscript provides a deeper insight into the chemical and adsorption interaction as well as mass transfer, which are scarcely studied. It is a well-organized and interesting work. Therefore, I would recommend a moderate revision before its publication.

1. Title should be revised. Change “reaction” to “destruction” or “degradation”

Answer: This was made. The new title is :

1. There is no necessary to mark “(1)…(4)” in the abstract.

Answer: This was modified.

1. Line 17, the full name of first abbreviation of “Ha” should be added.

Answer: This was made. Ha (Hatta Number)

1. Some important works relating catalytic ozonation and photocatalytic ozonation should be added into the Introduction to support the authors’ perspectives. For instance, Environ. Sci. Technol. 2020, 54, 5931; Chemical Engineering Journal, 2021, 404, 127075; Applied Catalysis B: Environmental, 2019, 251, 66-75; Journal of Hazardous Materials, 2019, 367, 456-464.

Answer: The new references was revised and added in the introduction section.

1. Line 298, no Figure 7.b is available here.

Answer: This was corrected.

1. Line 342, name of x-axis should be revised since it looks like a non-English word.

Answer: This was checked and modified.

1. Line 530, “This review was supported” should be corrected.

Answer: This was corrected.

1. Photocatalytic ozonation process is an attractive intensification approach for organic pollutant destruction. However, the most problem issue remain is the cost of this technique. The cost should include the set-up of special equipment and energy input. Perhaps, the authors can roughly calculate the electrical energy per order (EE/O, referred to Applied Catalysis B: Environmental, 2019, 251, 66-75) of ozonation, catalytic ozonation, and photocatalytic ozonation processes for comparison.

Answer: The table with the EE/O values were added.

1. Can the catalytic ozonation model also be useful for other ozonation catalysts instead of TiO2, such as Fe-MOFs (Chemical Engineering Journal, 2021, 404, 127075; Applied Catalysis B: Environmental, 2019, 251, 66-75; Journal of Hazardous Materials, 2019, 367, 456-464.)?

Answer: Yes, the model is generic account to, for other catalysts should be adjusted the respective properties. This was explained into the paper. 

1. Overall, this is a good work but the language usage should be polished.

Answer: This was made

Author Response File: Author Response.docx

Reviewer 2 Report

Thank you for an interesting read. The submitted manuscript deals with the advanced modeling implementation of a complex reaction system where many simultaneous processes in multiple phases occur (photocatalytic, catalytic, combined, direct reaction), and aims to show that it is able to solve by using advanced generic algorithm methods. The final outcome of the model predictions look good in most cases. The manuscript discusses thoroughly all scenarios and cases and summarizes well the results in the conclusion.

Here some minor comments:

Several abbreviations are not explained in body text, only in abstract, such as COz, PCOz, GA, VRPA

The introduction part should more clearly specify that this work is a continuation of previous work by Lara, using that data. 

Eventhough this manuscript focuses on the modeling of previous data, there is no mention of the fate of the formed products in this manuscript or in Lara (2019). Typically ozonation of DFC is not fully mineralized - potential toxic by-products can/are formed, such as hydroxylated DFC products (Coelho et al Sci. Total Environ. 2009, Saeid et al  Catalysts 2020; Krakstrom et al Ozone: Science & Engineering 2021). I think these should at least be mentioned in the text even if in this work, the fate of by-products is not on focus. 

The work of Lara which data is from, uses Diclofenac sodium salt, which is little different from native Diclofenac. The authors should mention this and also speculate that if the sodium salt has similar reactivity, I assume the salt is used instead of native compound due to solubility issues in water?

The work of Lara did not specify the exact gas composition. When you mention the concentration of ozone - is this pure gas ozone? Usually ozonators only produce a small wt% of ozone (around10%), whereas most of oxygen is unreacted (90%). How was it in this case? If oxygen is still present in the gas, are you assuming that it is not taking part in any of the reactions (table 1)?

Table 1: From where does one compound in reaction 10 come from:   O_L 2-  ?

Figure 7: Carga change to Load

Supplementary word file: change tiempo to time in all figures

Author Response

Thank you for an interesting read. The submitted manuscript deals with the advanced modeling implementation of a complex reaction system where many simultaneous processes in multiple phases occur (photocatalytic, catalytic, combined, direct reaction), and aims to show that it is able to solve by using advanced generic algorithm methods. The final outcome of the model predictions look good in most cases. The manuscript discusses thoroughly all scenarios and cases and summarizes well the results in the conclusion.

Here some minor comments:

Several abbreviations are not explained in body text, only in abstract, such as COz, PCOz, GA, VRPA

Answer: All abbreviations was explained in the text

The introduction part should more clearly specify that this work is a continuation of previous work by Lara, using that data. 

Answer: This was made in the introduction section. This study was a continuation of the work from Lara et al., where the experimental data to assess the models' predictions was obtained [22].

Eventhough this manuscript focuses on the modeling of previous data, there is no mention of the fate of the formed products in this manuscript or in Lara (2019). Typically ozonation of DFC is not fully mineralized - potential toxic by-products can/are formed, such as hydroxylated DFC products (Coelho et al Sci. Total Environ. 2009, Saeid et al  Catalysts 2020; Krakstrom et al Ozone: Science & Engineering 2021). I think these should at least be mentioned in the text even if in this work, the fate of by-products is not on focus. 

Answer: The authors are agreed with this statement. The explication about the by products is introduced. The paper is focus on modeling of main species but no intermediaries.

The work of Lara which data is from, uses Diclofenac sodium salt, which is little different from native Diclofenac. The authors should mention this and also speculate that if the sodium salt has similar reactivity, I assume the salt is used instead of native compound due to solubility issues in water?

Answer: This statement is correct. The explication was added for better understanding

The work of Lara did not specify the exact gas composition. When you mention the concentration of ozone - is this pure gas ozone? Usually ozonators only produce a small wt% of ozone (around10%), whereas most of oxygen is unreacted (90%). How was it in this case? If oxygen is still present in the gas, are you assuming that it is not taking part in any of the reactions (table 1)?

Answer: For this approach, the Oxygen no was taken account for the modeling. The composition of gas was included.

Table 1: From where does one compound in reaction 10 come from:   O_L 2-  ?

 Answer: The lattice oxygen is represented by  O_L 2- nomenclature in the model structure. The detail was include in the table

Figure 7: Carga change to Load

Answer: This was made

Supplementary word file: change tiempo to time in all figures

Answer: This mistake was corrected

Author Response File: Author Response.docx