Respon for Reviewer

Reviewer 1

No Comment Respon Page

1 comments for authors: The article needs a proofreading prior being published in the journal. The topic of research is quite interesting, however tha authors need to provide more discussion with regards the data obtained

Proof reading has been done and more discussion about the data obtained has been carried out

-

2 check wether the journal needs the Indoensia Abstract or not

The journal does not need the Indonesian abstract and we have deleted it

- 3 Which literature for this statement? [1] Veronica. N, Guru, T., Thatikunta, R.

and Reddy, S.N., 2015, Role of Nano fertilizers in agricultural farming, Int. J.

of Env. Sci. and Tech., 1(1), 1-3.

[2] Kottegoda, N., Munaweera, I., Madusanka, N. and Karunaratne, V., 2011, A green slow-release fertilizer composition based on urea-modified hydroxyapatite nanoparticles encapsulated wood, Current Science, 101 (1), 73-78.

4 this part need to be written in clearer and better sentences

This sentence have been written in clearer and better

5 Need literature? [26] Khodakovskaya, M.V., de Silva, K., Biris, A.S., Dervishi, E.

and Villagarcia, H., 2012, Carbon Nanotubes Induce Growth Enhancement of Tobacco Cells, ACS Nano 6 (3), 2128–2135.

6 be aware with tenses consistency This sentence have been rewritten in clearer and better

7 rewrite in a clear sentence The source of the material used for making the MWCNTs was benzene and ferrocene.

8 this procedure needs to add more detail information

MWCNTs produced from this method

were still relatively difficult to disperse and

there were still residual Fe impurities from

ferrocene. To resolve these issues, the

work was directed towards developing

methods to modify surface properties of

MWCNTs with functionalization. This

work was carried out using a reflux

process with a nitric acid solution for three

hours to attach the carboxylic group to the

tube wall. Another effect of this reflux

process is that the MWCNT wall will be

damaged and lead to the attachment of

the carboxylic group on the outer tube wall.

9 this part belong to Introduction Ok

10 rewrite in a better grammar At these temperatures, the source will split into more constituent carbons, a process which causes increasing diffusion of carbons on the surface of the catalyst metal [20]. Therefore, more MWCNTs form and their diameters will be smaller.

MWCNTs produced at a growth temperature of 1,000 C are slightly damaged; other studies have also determined that structural graphites cannot be formed at such temperatures [5].

11 any literature to support this statement?

For this paragraph is suggested by other reviewer to be removed

12 ion or metal? Ion Fe

²⁺

13 need grammar correction For this paragraph is suggested by other reviewer to be removed

14 how does the COOH group can be attached? need to add more explanation with regards the mechanism etc

MWCNTs functionalized using this method have an advantage in that they are soluble in various organic solvents due to possessing many functional groups such as carboxylic (COOH) ones derived from the reflux process with nitric acid [28,29].

15 uncommon to have a paragraph consist of only 1 sentence

We have repaired this paragraph 16 how does the MWCNT help the

dispersion in water?

This result shows that the functionalization process of MWCNTs has been able to help the dispersion process in water because there is a carboxylic group on the surface of MWCNTs which will increase the surface energy and reduce chemical affinity with dispersing media [39]. Surface functionalization can be developed to improve their dispersion, stability, and biocompatibility by introducing carboxylic groups

17 add more explanation why the higher concentration of MWCNT reduce the growth of the seeds?

At a concentration of 75 g/mL MWCNT,

aggregation of MWCNT within the roots

can occur, potentially causing negative

effects such as inducing nanotoxicity,

inhibiting nutrient transport, and affecting

plant growth [40].

Reviewer 2

No Comment Respon Page

1 Please mention the results of the characterization

the results of the characterization have been explained in the abstract

2 Indonesian abstracts are not needed

Ok

3 Reference? [1] Veronica. N, Guru, T., Thatikunta, R.

and Reddy, S.N., 2015, Role of Nano fertilizers in agricultural farming, Int. J.

of Env. Sci. and Tech., 1(1), 1–3.

4 The author should depart from the closest research on MWCNT carboxylation. Has there been no research on MWCNT carboxylation before?

Why MWCNT needs to be carboxylated?

What distinguishes this research from previous studies?

you did variations in the temperature of pyrolysis, please explain why temperature is important to study?

The author should state clearly the novelty of this research?

It has been explained in the paragraph 3 in introduction

the functionalization of MWCNTs or SWCNTs needs to be done through the reflux process, which increases its biocompatibility capabilities, particularly in terms of adsorption ability, electrostatic interactions, and covalent bonds by the presence of carboxylic groups on the walls [21,22].

In this study, we analyze the influence of functionalized MWCNT material for the treatment of mustard plants by soaking mustard seeds in a functionalized MWCNT solution at various concentrations.

There are several methods used for production of MWCNT including arc discharge, laser ablation, chemical vapour deposition and spray pyrolysis methods [15-20]. One of the easier methods to make MWCNT by adjusting its diameter is the spray pyrolysis method.

The length and diameter of MWCNT can be determined by growth temperature parameter and this is a crucial consideration for MWCNT applications.

Based on this research, we will get the certain characteristic of MWCNT, especially dimension and composition of the functionalized MWCNT for increasing growth of mustard plants.

Paragraph 3 in

Introduction

Paragraph 3 in

Introduction

Paragraph 2 in

Introduction

Paragraph 6 in

Introduction

5 you do not explain the reflux process here while in the discussion, you explain that there is a process of cleaning CNT with reflux

The source of the material used for making the MWCNTs was benzene and ferrocene. The optimal parameter of benzene as a carbon source and ferrocene as a catalyst was 3 g of ferrocene and 50 ml of benzene. The solution of ferrocene in benzene was introduced into the quartz reactor.

MWCNTs produced from this method were still relatively difficult to disperse and there were still residual Fe impurities from ferrocene. To resolve these issues, the work was directed towards developing methods to modify surface properties of MWCNTs with functionalization. This work was carried out using a reflux process with a nitric acid solution for three hours to attach the carboxylic group to the tube wall.

in procedure

6 Is there evidence for this statement or the literature that supports this opinion??

[20] Annu, A., Bhattacharya, B., Singh, P.K., Shukla, P.K. and Rhee, H.W., 2017, Carbon nanotube using spray pyrolysis: Recent scenario, J. of Alloys and Comp. 691, 970–982.

7 Is this roughness located on the inside or outside of the CNT wall?

If it's inside, how did you determine the roughness?

We have replaced the statement and there is reference:

MWCNTs produced at a growth temperature of 1,000 C are slightly damaged; other studies have also determined that structural graphites cannot be formed at such temperatures [5].

8 I don't see any references that you cited in this paragraph, and on the other hand you explain the

mechanism of the formation of CNTs.

How do you explain this mechanism while you are not basing this from the experimental results?

You have obtained a CNT as a result of synthesis, but this does not mean you can explain the mechanism that occurs, unless it is based on an analysis of the process

This paragraph has been deleted

9 I don't think this is necessary to be presented unless based on experimental evidence

The figure has been deleted

10 what acid did you use? In this research, HNO3 was used to reflux MWCNT.

11 Figure 5 should be placed after Figure 7 to explain how the Fe cleaning process occurs

You do not include the reflux process in the methodology description

Ok

This work was carried out using a reflux process with a nitric acid solution for three hours to attach the carboxylic group to the tube wall.

12 you did temperature variations in CNT synthesis, what was the result of acid washing for CNTs that were pyrolyzed at different temperatures?

Did it give different results?

we only washed MWCNT with nitric acid in CNTs grown at the optimum temperature at 900C

13 Figure 8 should be replaced or equipped with a table, so that changes in the composition of atoms before and after the reflux process become clear

We have replaced figure with a table

14 how did you determine that it is fields 002 and 100?

In the XRD study, how could the peak 002 have 2θ lower than the peak of 100? This is like impossible

the author should present MWCNT before and after functionalization, so that the changes occurred can be compared as shown in FTIR data

Figures 7a and 7b illustrate XRD analysis of MWCNTs before and after the functionalization process, respectively.

There are two graphite crystal orientations at 2 theta angles of 26.4 and 43.7 corresponding to the main plane of (002) and additional plane of (100) [32].

The results also show that the peaks of CNT (002) are in symmetry, indicating good crystallite dimensions and in agreement with Das, R., et.al. [33].

MWCNT has different chiralities, consisting of different layers and shows the same peak diffraction pattern (002) with graphite sheet. In addition, the honeycomb lattice structure of a single graphene cell caused the peak family (hk0) to be related to the (100) plane. The peak (hk0) is generated because of the curved nature of nanotubes [34].

The small peak at 37.4 in the MWCNTs

prior to functionalization suggests the

presence of Fe

3

C in the sample. The

metal carbide acts as an active catalyst in

the formation of tubular structures of

graphitic carbon and indicates the

impurity of the sample [35].

15 The author should explain what is the significant difference before and after functionalization. The review saw that there were differences in the two FTIR spectra, both from wave number position and transmittance value.

The author should explain from a chemical point of view, what

functional groups that increasing or decreasing or changing are.

And how changes in functional groups have implications for applications that will be used later

Figure 8a presents spectra of functionalized MWCNTs, comprising C-O groups at the wave number of 1,027 cm

^-1

, The wide transmission band at 3,450 cm

^-1

indicates the presence of O-H groups [18]. Wave numbers of 2,350 cm

^-1

are characteristic of C=C groups [37]. The weak peak at around 2,850 cm

^-1

is assigned to vibration modes of C-H or C- H

2

while the wave number of 1,720 cm

^-1

is attributed to C=O stretching vibrations in carboxyl groups [38]. Figure 8b shows spectra of non-functionalized MWCNTs.

The band at wave number 1,157 cm

^-1

is the absorption of C-O groups, while the wave number of 2,850 cm

^-1

is associated with the vibration modes of C-H or C-H

2

. Wave numbers of 2,350 cm

^-1

are characteristic of the C=C group due to the integrity of the hexagonal MWCNT structure.

In the case of functionalized MWCNTs, the characteristic O-H band appeared significantly broad and with higher intensity. This higher intensity is attributed to the increase in the number of hydroxyl groups on the MWCNT surface after functionalization. Decreasing the absorbance of C=C at 2,350 cm

^-1

indicates oxidation of carbon with the emergence of a peak at 1,645 cm

^-1

as carbonyl (C=O) stretching vibration of carboxyl groups, indicating the expansion of carboxylation on the surfaces of functionalized MWCNTs.

The FTIR results clearly demonstrate that the hydrophilic groups such as hydroxyls and carboxylics have been introduced onto the treated MWCNT surfaces. Thus, the functionalization of MWCNTs by the change in properties from hydrophobic to hydrophilic with the emergence of hydroxyl and carboxylates groups on its surface can be utilized as a nutrient transfer path within the plant tissue.

16 is there a comparison for un- fungsionalized MWCNT?

There is a un-funcsionalized MWCNT in Fig. 9

17 what is meant by control here? We have replaced “control” to “non