Enhancing the Removal of Sb (III) from Water: A Fe3O4@HCO Composite Adsorbent Caged in Sodium Alginate Microbeads
Round 1
Reviewer 1 Report
In this study Fe3O4@HCO/SA composite adsorbent was synthesized and assessed for Sb(III) removal from water. The idea to prepare this adsorbent utilizing Cerium (Ce) from waste sludge is interesting. Considering local availability of Ce rich optical and electronic manufacture processing sludge and Sb pollution in water in China, it is encouraging that researcher of the present study is trying to develop solution to address this problem.
I have found the manuscript is well written with good details experimental design and analysis. The results are well explained corresponding to experimental procedures.
However, I would suggest to improve the following points before consideration to publish this manuscript:
How Fe3O4@HCA adsorbent was prepared from ferriferous oxide and waste sludge? Although authors mentioned the preparation of Fe3O4@HCA/SA, it is important to give details how Ce was extracted from sludge to synthesize Fe3O4@HCA adsorbent? Line 84-85: please specify quantity i.e. what amount of adsorbent and SA were mixed? It is interesting to know what the sludge characteristics looks like - please provide a typical sludge characteristics table?
Some minor typo:
Line 149: "Cl on the surface decreased to 2.12%", please check if this is 0.12% which is in Fig 1(b).
Line 282: "low cost is low.." please correct it as "cost is low"
Author Response
Response to Reviewer 1 Comments
Points 1 and 2: How Fe3O4@HCA adsorbent was prepared from ferriferous oxide and waste sludge? Although authors mentioned the preparation of Fe3O4@HCA/SA, it is important to give details how Ce was extracted from sludge to synthesize Fe3O4@HCA adsorbent?
Response 1 and 2: The Fe3O4@HCO adsorbent has been prepared in our previous studies(Jun Zhang, Ren-jian Deng, Bo-zhi Ren, Baolin Hou, Andrew Hursthouse. "Preparation of a novel Fe3O4/HCO composite adsorbent and the mechanism for the removal of antimony (III) fromaqueous solution", Scientific Reports, 2019). Therefore, for brevity we did not introduce the preparation of Fe3O4@HCO adsorbent in this paper. And in line 60, we have introduced that “In previous studies, we have successfully prepared Fe3O4@HCO adsorbent with good removal effect on Sb(III) [25]”，and were tagged in red fond.
Points 3: Line 84-85: please specify quantity i.e. what amount of adsorbent and SA were mixed?
Response 3: For the quantity i.e. what amount of adsorbent and SA were mixed, We'll cover it later in the discussion, so it's not covered in Line 84-85. And in 3.1 SAB spheroidizing effect (Line 136-139), we discussed the amount of the adsorbent and SA.
Points 4: It is interesting to know what the sludge characteristics looks like - please provide a typical sludge characteristics table?
Response 4: The sludge characteristics have been introduced in our previous studies (Jun Zhang, Ren-jian Deng, Bo-zhi Ren, Baolin Hou, Andrew Hursthouse. "Preparation of a novel Fe3O4/HCO composite adsorbent and the mechanism for the removal of antimony (III) fromaqueous solution", Scientific Reports, 2019). Therefore, for brevity we did not introduce the sludge characteristics in this paper. And in line 60, we have introduced that “In previous studies, we have successfully prepared Fe3O4@HCO adsorbent with good removal effect on Sb(III) [25]”.
Points 5: "Cl on the surface decreased to 2.12%", please check if this is 0.12% which is in Fig 1(b).
Response 5: Without affecting the conclusion of the article, we delete the content " After the adsorption of Sb (III) by SAB, the content of Cl on the surface decreased to 2.12%, which indicated that there could be ion exchange during the adsorption process "
Points 6: "low cost is low.." please correct it as "cost is low"
Response 6: We accept the proposal, and correct “low cost is low” as "cost is low"
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and suggestions are in an attachment
Comments for author File: Comments.pdf
Author Response
Response to Reviewer 2 Comments
Points 1: Change the title - another stylistic form
Response 1: we have Change the title to “Enhancing removal of Sb (III) from water solution: a Fe3O4@HCO composite adsorbent caged in Sodium Alginate microbeads”
Points 2: Complete the keywords (with adsorption)
Response 2: We have added the keywords “Adsorption”
Points 3: The term 'water' in both the title and the all article should be replaced by a water solution or waste water - very high concentrations were used in the studies
Response 3: We have modified water solution or waste water to replace water, and were tagged in red fond.
Points 4: Do not use the word physi-sorption (what is this?)
Response 4: We have modified physisorption to replace physi-sorption, and were tagged in red fond.
Points 5: Complete the introduction: with data on antimony Sb concentrations in the water environment and adsorption capacity Sb on other sorbents
Response 5: According to the experts’ opinion, we have increased the comparison of adsorption performance between SAB and other iron series adsorbents, reference 19 and 43,and were tagged in red font
Points 6: line 82 - chapter 2 - change the name
Response 6: We've changed the name to Materials and methods
Points 7: Line 107 what does "reserve" mean?
Response 7: The standard reserve solution is the solution used in the subsequent test, and the antimony solution used in the subsequent test is obtained by dilution of the standard reserve solution.
Points 8: Complete the methodology for pH and concentration of other compounds in Sb standard solution
Response 8: In this study, the simulated wastewater is used in the experiment. For the concentration of other compounds in Sb standard solution, we have added the content “The interfering ions used in the experiment are all anionic sodium salts” in line112, and were tagged in red font.
Points 9: Complete the applications with:
- SAB adsorption capacities,
- How to deal with the used adsorbent (can it be regenerated?)
Response 9: The SAB adsorption capacities have introduced in line 235 and table 2, and were tagged in red font. For the used adsorbent, we will study its recycling in the future research.
Author Response File: Author Response.pdf
Reviewer 3 Report
Reviewed manuscript presents the results of sorption and kinetics of Sb onto new developed sorbent. Fe3O4@HCO composite was bounded with sodium alginate and applied to sorption process. Generally, I found this work very interesting. The outline of manuscript is clear, most data are presented and described properly. Below some remarks:
Line 84: Please provide exact mass of both components
Line 87: How many drops? What was the volume?
Line 91: remove “(named SAB)”
Line 134: I can’t find Fig. S1.
Line 135: It will be better to say, that Fe3O4@HCO to SA ratio is between 1.25 to 1.33.
Lines 148-150: I’d say that Sb exchanged with Ca but definitely not with opposite charged Cl.
Line 164: remove “from the fig”
Line 210: Did authors test statistically the effects presented in Fig3?
Author Response
Response to Reviewer 3 Comments
Points 1: Line 84: Please provide exact mass of both components
Response 1: For the quantity i.e. what amount of adsorbent and SA were mixed, we’ll cover it later in the discussion, so it's not covered in Line 84-85. And in 3.1 SAB spheroidizing effect (Line 136-139), we discussed the amount proportion of the adsorbent and SA.
Points 2: Line 87: How many drops? What was the volume?
Response 2: In this process, we drop the previously prepared mixture into 5% calcium chloride solution to solidify it into SAB microspheres, so the volume of the added mixture is not considered here.
Points 3: Line 91: remove “(named SAB)”
Response 3: We accept the proposal, and remove “named SAB”
Points 4: Line 134: I can’t find Fig. S1.
Response 4: Omission of fig. S1 due to negligence, we have added fig. S1 to the article appendix.
Points 5: Line 135: It will be better to say, that Fe3O4@HCO to SA ratio is between 1.25 to 1.33.
Response 5: We accept the proposal, and Change it to “As shown in Table 1, SAB microspheres have better spheroidizing effect when the concentration of the Fe3O4@HCO to SA ratio is between 1.25 and 1.33 (Fig. S1).”
Points 6: Lines 148-150: I’d say that Sb exchanged with Ca but definitely not with opposite charged Cl.
Response 6: Without affecting the conclusion of the article, we delete the content " After the adsorption of Sb (III) by SAB, the content of Cl on the surface decreased to 2.12%, which indicated that there could be ion exchange during the adsorption process "
Points 7: Line 164: remove “from the fig”
Response 7: We accept the proposal, and removal “from the fig”
Points 8: Line 210: Did authors test statistically the effects presented in Fig3?
Response 8: For the results in Figure 3, we have done repeated experiments to verify the experimental results.
