Photocatalytic and Sonocatalytic Degradation of EDTA and Rhodamine B over Ti⁰ and Ti@TiO₂ Nanoparticles

Round 1

Reviewer 1 Report

In general the paper, despite rich of data is quite confusing, presenting the results in two degradation of molecules and two methods. I guess that a reorganization in two paper could be useful for clarity.

In particular the  Ti0 nanoparticles are expected to be inefficient under photocatalysis, so this is no a particular finding.

The preparation or the acquisition of Ti0 nanoparticles passivated by the air should be  reported.

In which consists the air passivation?

XPS measurement should be added in the characterization to show the oxidation state of Ti

Following some observations

Experimental setups

2.4.1. Photocatalytic Experiments

“…..The obtained values of light power were equal to 8.9 and 0.6 W for vis/NIR and UV spectral ranges respectively, which provides the close spec-tral match to solar spectrum…”.Intensity,  no power of the radiation must be reported.

“On the other hand, EDTA kinetics are followed following the change in the absorption peak of (Fe-TPTZ)2+ complex where TPTZ stands for Bis (2,4,6-tripyridyl-s-triazine)[20].” It is not clear how EDTA is detected.

EDTA Study

3.2.1. Kinetics of Photocatalytic EDTA Degradation

“Degradation of EDTA under the white light of Xe lamp was studied in the presence of both air passivated Ti0 and Ti@TiO2 NPs under two different gas atmospheres Ar and Ar/20%O2. The kinetics of EDTA photocatalytic degradation tends to vary based on the choice of the catalyst, gas atmosphere and bulk temperature. Regardless of the chosen conditions, all kinetic curves are fitted with the zero-order kinetic model.”

All the trends should be shown, it not sufficient the description of zero order model, but also the accordance with the first order kinetics, since the low activity shown.

“Figure 3 Yields of CO2 for Ar/20%O2 atmosphere (grey) and H2 for Ar atmosphere (blue) yields obtained upon photocatalytic degradation of 5 mM EDTA solution over Ti@TiO2 catalyst under Ar/20%O2 and Ar at different temperatures (catalyst concentration 0.12 g.L-1, V = 65 mL, PXe light = 8.2 W). “

Has been evaluated the agreement between the evolution of CO2 and the removal curves?

 

3.2.5. Rhodamine B Degradation

Also for the RB a table of comparison of consumed power must be reported to understand the convenience to choose one method with another

Author Response

Please see the attachement.

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript described the synthesis of Ti@TiO2 nanoparticles for photocatalytic and sonocatalytic degradation of EDTA and dye. This manuscript may be acceptable after proper revision. The following are specific comments.

 

1. The authors should elaborate more on the novelty of this work in the Introduction. Why the authors use Ti0 and Ti@TiO2 for degradation of pollutants? Also, authors have to do a sufficient literature survey because some important progress in related TiO2-based catalysts, e.g., J. Hazard. Mater., 2019, 368, 468-476; Appl. Catal., B, 2021, 291, 120118; J. Cleaner Prod., 2021, 287, 125462; Nanotechnology, 2021, 32, 285601; J. Environ. Chem. Eng., 2021, 9, 104828; J. Hazard. Mater., 2021, 401, 123402;
2. In experimental section, the author should clearly state the reaction condition, e.g., is there any UV-light filter and any temperature control system used in the photocatalytic reaction system?
3. The analysis of reaction kinetics can be done based on the Langmuir–Hinshelwood (LH) model. Specifically, what is the rate-limiting step of the reaction? Please refer to Applied Catalysis B: Environmental 227 (2018) 114–122; Chemical Engineering Journal 387 (2020) 124098.
4. In order to construct the electronic band, the authors should conduct the analyses by various techniques such as MS plot, EIS, photocurrent, DRS, etc.
5. Compare the photocatalysts performance of this study with the existing literatures, in particular for those using TiO2-based catalysts.

 

 

Author Response

Please see the attachement

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

This manuscript has been revised well and ready to be published.