Preparation of Hydrogels Based Radix Isatidis Residue Grafted with Acrylic Acid and Acrylamide for the Removal of Heavy Metals
Round 1
Reviewer 1 Report
The manuscript describes a GOOD work AND is well presented. Authors need the following points to be included before publication.
1. English needs improvement throughout the manuscript and spelling should be checked thoroughly.
2. Whenever working with supported or coupled materials, I suggest comparing the efficiency between the pure material (RIR) and the hydrogel (RIR/AA-co-AM). Perhaps the pure material is as effective as the hydrogel.
3. I would advise the characterization of nitrogen adsorption / desorption (BET) before and after the polymerization, results as surface area and pore volume are important properties in the characterization of adsorbents.
4. Legends in Figures 7, 8, and 9 are confusing and should be rewritten. Also, there are no need for figures 7a, 8a, and 9a, the information is repeated.
5. I recommend testing the prepared hydrogel for heavy metal removal from real samples and reporting how efficiency changes in the presence of other ions.
Author Response
Dear reviewer,
Thanks so much for your comments and suggestion. Attached the "response to reviewer 2".Please see the attachment.Thanks.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript has enough novelty with sufficient results but some major revisions must be performed to improve its quality. The following comments are strongly suggested for authors:
The abstract should be shortened and unnecessary explanations should be removed. The authors should present important results.
The introduction should be improved and some sentences about hydrogels and their features should be added to the manuscript. The following articles are strongly suggested: A 4arm-PEG macromolecule crosslinked chitosan hydrogels as antibacterial wound dressing. Carbohydrate Polymers (2022); Synthesis and properties of Poly(vinyl alcohol) hydrogels with high strength and toughness. Polymer Testing (2022).
The novelty of this study must be presented at the end of the introduction and highlighted.
Line 123: The chemical name of cadmium chloride hydrate should be checked.
Line 234: What is it the stretching vibration of C¼O?? Please explain? Is it a functional group? Or is a typo error?
FTIR analysis should be cited with suitable references.
On Figure 5, the functional groups should be written instead of wavenumbers.
To better interpretation of the results the following papers should be used: Efficient removal of iron from red gypsum via synergistic regulation of gypsum phase transformation and iron speciation. Science of The Total Environment (2021); Pollution characteristics and source analysis of microplastics in the Qiantang River in southeastern China. Chemosphere (2022); Ultrasonic power combined with seed materials for recovery of phosphorus from swine wastewater via struvite crystallization process. Journal of environmental management (2021); Insight into the enhanced sludge dewaterability by tannic acid conditioning and pH regulation. The Science of the total environment (2019)
The resolution of figures should be improved.
It is recommended to use non-linear forms of kinetic and equilibrium equations instead of linear forms.
The authors should compared their results in Table 3 with other studies such as: The remediation efficiency of heavy metal pollutants in water by industrial red mud particle waste. Environmental Technology & Innovation (2022)
Author Response
Dear reviewer,
Thank you very much for your valuable comments on our manuscript.Attached the "response to reviewer 2",please see the attachment.Thanks.
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript " Preparation of Hydrogels based Radix Isatidis residue grafted with AA and AM for the Removal of Heavy Metals" includes a lot of work and contains many data. It could be published in your journal, but with revision and re- reviewing. I make the following comments:
- The AA and AM abreviations in the manuscript title and abstract are inappropriate and should be revised;
- The bio-adsorbent name is an unused term and should be changed. The usual word is biosorbent. Furthermore, it is not unitary used in text. Thus, the bio-adsorbent name from Introduction has been used as adsorbent in Results and Discussion section.
- Introduction: The research questions are NOT clearly defined in the state-of - the art context;
- Results and discussion: The authors do not give enough insight into the presentation and discussion of results;
- Line 154-156 - "Because RIR/PAA4 and RIR/PAM3 have better physical properties than other hydrogels of the same series, only RIR/PAA4 and RIR/PAM3 are compared with RIR/AA-co-AM in this following study" - Explanation and comparative data are required
- References for eq.(1), eq.(2), eq.(3) must be given;
Line 282-283- "Since heavy metal ions would precipitate when the pH was greater than 5.5, the adsorption capacities
of the adsorbents were only explored pH between 1-5". An explanation is required;
- Line 382- typo(Cr2+) that must be corrected ;
- The references for the kinetic models are wrong given. The original articles should be shown;
Table 1: What means qe1 and qe2?
- References for the adsorption isotherms (Langmuir and Freundlich) are missing . These must be given.
- From Figure 12 it is not obvious what are the ion exchange and electrostatic interactions;
- Comparison made in Table 3 is not conclusive, because the experimental conditions are not mentioned
Author Response
Dear reviewer,
Thanks for you very valuable comments and suggestion on our manuscript.Attached the "response to reviewer 3",please see the attachment.Thanks.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The manuscript quality has been improved and can be published in the journal of Water.
Reviewer 3 Report
The authors have properly revised the manuscript that can now be publised
