Aloe vera as Promising Material for Water Treatment: A Review

Round 1

Reviewer 1 Report

Aloe vera has been cultivated for many centuries for its beneficial properties, finding application in a wide range of medical and health products, however, it can be also used as an adsorbent. Therefore the manuscript is interesting. Nevertheless, major corrections are needed before the publication of the manuscript. 

Title: The title accurately reflects the content and it does not need revision.

Abstract and Conclusions: Abstract and Conclusions are too simple and general and do not adequate and therefore should be rewritten.

Introduction and other parts: The paper should describe the novelty, without the repetition of information about the different types for adsorption, adsorbents etc. The same as paragraph 2. 
In the whole paper the same style, units etc. should be used. Also please change 'Arsenic' to 'arsenic', ºC to K, Tabe 1 to Table 1, Dubinin-Radushkevik to Dubinin-Radushkevicz, water depollution to water treatment etc.
Add the description of the data presented in Table 1.
As for content, 4 main parts can be distinguished: description of Aloe vera as coagulant/flocculant for wastewater treatment, as biosorbent for pollutant removal, as flocculant for wastewater sludge treatment and promising material for water depollution. 

What is more, the manuscript contains several grammatical errors and weakly constructed sentences that require careful revision by the authors. 

Author Response

1. Abstract and Conclusions: Abstract and Conclusions are too simple and general and do not adequate and therefore should be rewritten.

The abstract and the conclusion were re-written

2. Introduction and other parts: The paper should describe the novelty, without the repetition of information about the different types for adsorption, adsorbents etc. The same as paragraph 2. 

We thank the reviewer for this comment. In the introduction is very important to describe the conventional technologies used for wastewater treatment. Then, we introduce the originality of using Aloe vera. At the end of the introduction, AV was introduced.

Similarly, in section 2 (Aloe vera as coagulant/flocculant for wastewater treatment), is very important to introduce the health problem associated to the use of chemicals in the commonly coagulation/flocculation process. This give raison to the introduction of AV materials as coagulant/flocculant to substitute chemicals. Therefore, is very important to keep this information in the manuscript.

3. In the whole paper the same style, units etc. should be used.

The paper was revised and the style of units was arranged

4. Also please change 'Arsenic' to 'arsenic', ºC to K, Tabe 1 to Table 1, Dubinin-Radushkevik to Dubinin-Radushkevicz, water depollution to water treatment etc.

'Arsenic' was corrected  to 'arsenic'

All temperature values was changed from ºC to K

'Dubinin-Radushkevik' was corrected to 'Dubinin-Radushkevicz'

In the manuscript 'water depollution' was changed by 'water treatment'

5. Add the description of the data presented in Table 1.

The most important data related to the use of AV in the coagulation-flocculation are already discussed in the section, and Table 1 summarized this data. Therefore, no need to re-dscribe the data

6. What is more, the manuscript contains several grammatical errors and weakly constructed sentences that require careful revision by the authors. 

The paper was revised carefully and grammatical errors were corrected

Reviewer 2 Report

This work investigates the use of different forms of Aloe Vera for water treatment. Processes like flocculation or adsorption. The work belongs to processes however needs at least major revision before publication

 

Some points

• The title “ALOE VERA.”
• The manuscript is “REVIEW” and not “RESEARCH PAPER.”
• COD and BOD = Chemical Oxygen Demand and Biochemical Oxygen Demand
• The English language needs revision in several expressions
• “Similarly, 96.5 % turbidity removal from Indrayani stream water was 87 reached with 5 mg/l of liquid AV used as coagulation aid in the presence of alum (mg/l). However, for the same water, the use AV liquid as flocculant aid allowed the removal of 96.2 % of the turbidity.”  From these sentences, I cannot understand the difference between the 2 experiments..the second is without aluminum? Then  tha aloe vera is not flocculant aid but flocculant
• Table 2 “AV gel dried (800°C for 24 h), redried using a muffle furnace
• (4000°C for 30 min).” the authors mean 400 C?

What is missing is a perspective /conclusion and future direction from the authors. What of these processes did authors believe have more chances? Where must future work be the focus?

Author Response

1. The title “ALOE VERA.”

the word “Aleo”was corrected  to “Aloe”.

2. COD and BOD = Chemical Oxygen Demand and Biochemical Oxygen Demand

Te abbreviations of COD and BOD were added

3.The English language needs revision in several expressions

The manuscript was revised and the English language was corrected

4. “Similarly, 96.5 % turbidity removal from Indrayani stream water was 87 reached with 5 mg/l of liquid AV used as coagulation aid in the presence of alum (mg/l). However, for the same water, the use AV liquid as flocculant aid allowed the removal of 96.2 % of the turbidity.”  From these sentences, I cannot understand the difference between the 2 experiments. The second is without aluminum? Then  tha aloe vera is not flocculant aid but flocculant

Also, in the second experiment, alum was used at the same concentration and aloe vera was used as flocculant aid (10 mg/l).

The statement was corrected: "Similarly, 96.5% turbidity removal from Indrayani stream water was reached with 5 mg/l of liquid AV used as coagulation aid in the presence of alum (56 mg/l). However, for the same water and using the same quantity of alum (56 mg/l), the use of AV liquid as flocculant aid (10 mg/l) allowed the removal of 96.2% of the turbidity."

 

5. Table 2 “AV gel dried (800°C for 24 h), redried using a muffle furnace

(4000°C for 30 min).” the authors mean 400 C?

The data were corrected: AV gel dried at 80°C (353 K), and redried using a muffle furnace at 400°C (673 K)

6. What is missing is a perspective /conclusion and future direction from the authors. What of these processes did authors believe have more chances? Where must future work be the focus?

The conclusion was re-written

Reviewer 3 Report

The manuscript reviews the use of Aloe Vera in wastewater treatment. The manuscript is generally well written and scientifically valid. However, some improvements are needed before it can be accepted for publication in Processes. Please refer to my comments listed below.

• There is a typo in the title, “Aleo”. The typo is present also in other part of the text (L54, L264).
• Abstract is too short and does not convey the necessary information.
• L70: ref. 21, the reference is not consistent with the message of the paragraph.
• No figures are present in the text. A couple would increase the general quality of the manuscript.
• More discussion is generally needed. The manuscript describes a lot of previous experiences but they should be also better discussed.

 

Author Response

1. There is a typo in the title, “Aleo”. The typo is present also in other part of the text (L54, L264).

The manuscript was revised and the word “Aleo”was corrected  to “Aloe”.

2. Abstract is too short and does not convey the necessary information.

The abstract was ameliorated

3. L70: ref. 21, the reference is not consistent with the message of the paragraph.

The reference 21 was replaced by "Martyn, C.N.; Osmonda, C.; Edwardson, J.A.; Barker, D.J.P.; Harris, E.C.; Lacey, R.F. Geographical Relation Between Alzheimer's Disease and Aluminum in Drinking Water. Lancet, 1989, 14: 59. "

4. No figures are present in the text. A couple would increase the general quality of the manuscript.

A Figure 1 was added describing the AV preparations and its application in wastewater treatment

5. More discussion is generally needed.

Statements were added (L 146-151; L 271-275)

Round 2

Reviewer 1 Report

In my opinion, the paper was improved and deserves to be published in Processes.

Reviewer 2 Report

The authors revised their work according to the reviewers suggestions