Synthesis of a Chemically Modified Biosorbent Based on the Invasive Plant Leucaena leucocephala and Its Application in Metformin Removal
, Laiza Bergamasco Beltran 1, Anna Carla Ribeiro 1, Rosângela Bergamasco 1,*, Milena Keller Bulla 1, Rhana Keterly Facina 2 and Gustavo Affonso Pisano Mateus 2Round 1
Reviewer 1 Report
The current study reported the adsorptive removal of metformin ( well known pharmaceutical) from water using biosorbent produced from Leucaena leucocephala pods. The row pods were dried, and chemically treated with methanol and nitric acid and then calcined at 300 ℃. The following adsorption parameters were considered; temperature, contact time, adsorbent dosage, pH, and initial metformin concentration. The isotherms and kinetics were analyzed. The effect of ionic strength using different salts (NaCl, CaCl2 and MgCl2) on metformin removal was investigated. Comparison table is included to compare the adsorption capacity with other adsorbents. The paper has a good idea. But still a lot of experiments are required to make it suitable for Water journal.
Novelty of the paper requires more elaboration in the introduction part. Literature review about the use of this material in removing pollutants from water. Then any other biosorbents utilized for the removal of metformin then propose the research gap.
Structure of the paper must be improved, divide the discussion into sections. Separate characterizations from adsorption experiments.
Similarity ithenticate report 30%, work to decrease.
Methodology of material preparation is not sufficient, the materials is calcined at 300 ℃, is it biochar or burned under oxygen. Elaborate more in methodology and discussion, new parts are required.
How the authors measured the concentration of metformin, this procedure must be mentioned in detail.
Figures such as Figure 1, 2 and Figure 5 is not clear. Improve the quality of all figures.
The FTIR (Fig. 3) requires a lot of improvement. The peaks has to be well organized, it is recommended to re conduct the FTIR spectra.
So far, 3 point to detect the effect of pH is not enough.
It is recommended to do some experiments at low concentration of Metformine, I mean concentrtations lower than 1 ppm.
No reusability (regeneration) studies were considered.
The adsorption mechanism has to be provided in detail, conduct the FTIR after adsorption, it is also highly recommended to conduct the XPS analysis to confirm the adsorption mechanism.
A lack of basic characterization data, XRD, SEM after adsorption, TGA. EDS before and after adsorption. CHNS analysis for biosorbents to check the composition is also highly recommended for biosorbents.
It is suggested to do column adsorption experiments.
How were the thermodynamics estimated? Give a clear procedure.
In kinetics, the authors claim that intra-particle diffusion used to study the kinetics however, it is not considered in comparison.
In conclusion “L. leucocephala for the removal of contaminants from aqueous solutions.” For metformin, it is OK, but for other contaminants, it is well reported in many articles that this material used for the removal of contaminants.
I regret to inform that the paper in the current form is not acceptable, a lack of characterization and tests are required to improve the quality of this manuscript. Therefore, my decision is to reject this paper, If the authors did significant enhancement, I would review the manuscript again.
The English level is very good.
Author Response
June 20, 2023.
Dr. Ali Ayati and Dr. Bahareh Tanhaei
Editors in Chief, Water
Ms. Milena Milosavljevic
Section Managing Editor
First of all, we would like to acknowledge and thank the reviewers for the very positive and
extremely helpful comments to improve the article. We hope that all corrections and answers
will be satisfactory to the reviewers. Given your comments, we had performed the suggested
modifications; specific comments and answers to questions are below. The changes we made
in the manuscript are highlighted in yellow.
Reviewer 1
The current study reported the adsorptive removal of metformin ( well known
pharmaceutical) from water using biosorbent produced from Leucaena leucocephala
pods. The row pods were dried, and chemically treated with methanol and nitric acid
and then calcined at 300 ℃. The following adsorption parameters were considered;
temperature, contact time, adsorbent dosage, pH, and initial metformin concentration.
The isotherms and kinetics were analyzed. The effect of ionic strength using different
salts (NaCl, CaCl2 and MgCl2) on metformin removal was investigated. Comparison
table is included to compare the adsorption capacity with other adsorbents. The paper
has a good idea. But still a lot of experiments are required to make it suitable for Water
journal.
Novelty of the paper requires more elaboration in the introduction part. Literature
review about the use of this material in removing pollutants from water. Then any other
biosorbents utilized for the removal of metformin then propose the research gap.
Answer: Thank you for the observation. About the use of others biosorbents for the removal
of metformin, there is a phrase in the introduction: “Regarding to MET wastewater removal
through plant based adsorbents, literature reports the use of Moringa oleifera seed husks
functionalized with iron oxide nanoparticles [15], activated carbon from Zea mays tassels
Av. Colombo, 5.790 • Câmpus Universitário Bloco: I90 – Centro de Ciências da Saúde • CEP 87.020-900 • Maringá – PR.
Fones: (44) 30114924 • Fax: (44) 3011-4782 • E-mail: [email protected]• Internet: www.uem.br
[16], orange peel [17] and chichá-do-cerrado (Sterculia Striata St. Hil. et Naud) fruit shells
[18]”.
We include papers about the use of Leucaena leucocephala removing pollutants from water.
Structure of the paper must be improved, divide the discussion into sections. Separate
characterizations from adsorption experiments.
Answer: Thank you for the suggestion. The discussion was divided in sections.
Similarity ithenticate report 30%, work to decrease.
Answer: Thank you for the observation. The authenticity of the report was checked.
Methodology of material preparation is not sufficient, the materials is calcined at 300 ℃,
is it biochar or burned under oxygen. Elaborate more in methodology and discussion,
new parts are required.
Answer: Thank you for the suggestion. The methodology and discussion were more detailed.
How the authors measured the concentration of metformin, this procedure must be
mentioned in detail.
Answer: The methodology for measuring the concentration of metformin is described in the
text, as following: “
Figures such as Figure 1, 2 and Figure 5 is not clear. Improve the quality of all figures.
Answer: Thank you for the observation. The quality of all figures was improved.
The FTIR (Fig. 3) requires a lot of improvement. The peaks have to be well organized, it
is recommended to re conduct the FTIR spectra.
Answer: Thank you for your observation. Unfortunately the analysis was done in another
institution, we have to send the sample and pay for the analysis and we have a time of waiting
for the results, due to these obstacles it is not possible to reconduct the FTIR spectra.
So far, 3 point to detect the effect of pH is not enough.
Av. Colombo, 5.790 • Câmpus Universitário Bloco: I90 – Centro de Ciências da Saúde • CEP 87.020-900 • Maringá – PR.
Fones: (44) 30114924 • Fax: (44) 3011-4782 • E-mail: [email protected]• Internet: www.uem.br
Answer: Thank you for the observation. The effect of pH analysis was based on other papers
that our research group already published and we use 3 pH points. Some articles that use the
same methodology were cited below:
https://doi.org/10.1080/09593330.2022.2164745
https://doi.org/10.1002/cjce.24861
https://doi.org/10.1016/j.cep.2021.108694
https://link.springer.com/article/10.1007/s11356-022-19187-x
https://doi.org/10.1080/09593330.2022.2138786
https://doi.org/10.1016/j.indcrop.2020.113200
https://doi.org/10.1016/j.micromeso.2021.111328
It is recommended to do some experiments at low concentration of Metformine, I mean
concentrations lower than 1 ppm.
Answer: Thank you for the observation. Unfortunately it is not possible to analyze
concentrations below 5 ppm due to the spectrophotometric methodology used.
No reusability (regeneration) studies were considered. The adsorption mechanism has to
be provided in detail, conduct the FTIR after adsorption, it is also highly recommended
to conduct the XPS analysis to confirm the adsorption mechanism.
A lack of basic characterization data, XRD, SEM after adsorption, TGA. EDS before
and after adsorption. CHNS analysis for biosorbents to check the composition is also
highly recommended for biosorbents.
Answer: Thank you for the observation. We don’t consider the regeneration studies due to the
following reasons: a) it is a invasive plant and it has an easy availability to collect; b) the
specific analysis (FTIR, MEV) were done in another's laboratories and we had to pay for it
and waiting for the results, so we have a short time to have all the experiments done to send to
this Water special edition. We apologize for some lack of information, but we make an effort
to produce results for suitable publication.
It is suggested to do column adsorption experiments.
Answer: Thank you for the suggestion. We consider the column experiments, but we have a
short time to have all the experiments done to send to this Water special edition. We are
considering continuing the studies with column adsorption experiments for future papers.
How were the thermodynamics estimated? Give a clear procedure.
Answer: The thermodynamics procedure are estimated according to Hayward, D.O.;
Trapnell, B.M.W. Chemisorption; 2nd ed.; Butterworths: Washington DC, 1964.
Av. Colombo, 5.790 • Câmpus Universitário Bloco: I90 – Centro de Ciências da Saúde • CEP 87.020-900 • Maringá – PR.
Fones: (44) 30114924 • Fax: (44) 3011-4782 • E-mail: [email protected]• Internet: www.uem.br
In kinetics, the authors claim that intra-particle diffusion used to study the kinetics
however, it is not considered in comparison.
Answer: Thank you for the observation. The intra-particle diffusion was included in kinetics
studies.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Fig 5 is not clear that should be improved.
There is spelling mistakes in some sentence.
Author Response
Reviewer 2
Comments and Suggestions for Authors
Fig 5 is not clear that should be improved.
Answer: Thank you for the observation. The Figure 5 quality was improved.
Author Response File: Author Response.pdf
Reviewer 3 Report
After reading the work entitled “Synthesis of a biosorbent based on the invasive plant Leucaena leucocephala and its application in metformin removal” by Cusioli et al., I would recommend to accept it after the authors respond the following comments properly.
Please see my comments below.
1. For more specific, the title should add with “chemically modified biosorbent” or “HNO3-modified biosorbent” rather than “biosorbent” only.
2. Please insert the significance of this study in the abstract.
3. What are benefits of adsorbents from the invasive plant Leucaena leucocephala? Give some statements in the introduction.
4. Please state the novelty of this study at the end of the introduction.
5. In Table 1, the unit of “Stirring Speed” should be moved in above line.
6. In Eq. 1, if there is “qe”, what unit is it? At the same for Ci, Cf. Please define.
7. In Eq. 3, the equation is wrongly written, “qe^t)” should be “qe^2”. Please correct.
8. The unit of kF in Eq. 6 is wrongly written, it should be “[(mg/g)/(mg/L)^1/n]”
9. Please be in consistent between h and hour, “/” and “^-1”, etc.
10. Fig. 2 is too low in resolution. Please improve and insert error bars for each data point.
11. In Fig. 6. “0,1 M” and “0,3 M” should be ““0.1 M” and “0.3 M”. Please improve and insert error bars for each data point.
12. Please give an explanation of adsorption mechanism of metformin over the LLMO.
13. Table 6 should be expanded by adding more refs.
Thank you!
Minor editing of English language should be required
Author Response
Reviewer 3
After reading the work entitled “Synthesis of a biosorbent based on the invasive plant
Leucaena leucocephala and its application in metformin removal” by Cusioli et al., I
would recommend to accept it after the authors respond the following comments
properly.
Please see my comments below.
1. For more specific, the title should add with “chemically modified biosorbent” or
“HNO3-modified biosorbent” rather than “biosorbent” only.
Answer: Thank you for the suggestion. We modified the title: “Synthesis of a chemically
modified biosorbent based on the invasive plant Leucaena leucocephala and its application in
metformin removal”.
2. Please insert the significance of this study in the abstract.
Answer: Thank you for the suggestion. We include the significance of this study in the
abstract.
3. What are benefits of adsorbents from the invasive plant Leucaena leucocephala? Give some
statements in the introduction.
Answer: Thank you for the suggestion. We include the benefits of using adsorbents from the
invasive plant Leucaena leucocephala.
“Focusing on the environmental field, L. leucocephala has been widely investigated as a
coagulant agent [22] and biosorbent for contaminants removal from wastewater, such as
heavy metals (Pb2+, Cd2+ and Ni2+) [23,24] and malachite green dye [25]. The L.
leucocephala pod has already been used by the adsorption process to remove contaminants,
such as: hexavalent chromium and malachite green dye[25,26]”.
4. Please state the novelty of this study at the end of the introduction.
Answer: Thank you for the observation. We include the novelty of the study in the
introduction.
5. In Table 1, the unit of “Stirring Speed” should be moved in above line.
Answer: Thank you for the observation. We made the correction.
6. In Eq. 1, if there is “qe”, what unit is it? At the same for Ci, Cf. Please define.
Answer: Thank you for the observation. We include the units for qe, Ci, Cf.
7. In Eq. 3, the equation is wrongly written, “qe^t)” should be “qe^2”. Please correct.
Answer: Thank you for the observation. We corrected it to “qe^2”.
8. The unit of kF in Eq. 6 is wrongly written, it should be “[(mg/g)/(mg/L)^1/n]” .
Answer: Thank you for the observation. We corrected it to “[(mg/g)/(mg/L)^1/n]”.
9. Please be in consistent between h and hour, “/” and “^-1”, etc.
Answer: Thank you for the observation. We made the corrections in the text.
10. Fig. 2 is too low in resolution. Please improve and insert error bars for each data
point.
Answer: Thank you for the observation. We improve the Figure 2 resolution.
11. In Fig. 6. “0,1 M” and “0,3 M” should be ““0.1 M” and “0.3 M”. Please improve and
insert error bars for each data point.
Answer: Thank you for the observation. We made the corrections in figure 6.
12. Please give an explanation of adsorption mechanism of metformin over the LLMO.
Answer: Thank you for the suggestion. We include an explanation about the adsorption
mechanism of metformin over LLMO in the text. It is highlighted in yellow.
13. Table 6 should be expanded by adding more refs.
Answer: Thank you for the suggestion. We include more references about metformin removal
with biosorbents.
Thank you!
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Accept
Accept
Author Response
Thank you Reviewer
Reviewer 3 Report
The paper can be now accepted for publication.
Author Response
Thank you Reviewer
