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by
  • Maryam Hanif 1,
  • Ijaz Ahmad Bhatti 1 and
  • Fahad A. Alharthi 6
  • et al.

Reviewer 1: Somayeh Taghavi Reviewer 2: Anonymous Reviewer 3: Anonymous

Round 1

Reviewer 1 Report


Comments for author File: Comments.pdf


Author Response

Response to Reviewer 1 Comments

This paper attempts to study production of biodiesel from three types of waste oils over nanomagnetic catalyst (CaO/Fe2O3/Feldspar). The aim of the work and the followed methodology to reach the aim are logical. However, some comments are mentioned bellow that may help to improve the quality of the manuscript. A major revision is suggested for the manuscript:

Comments and Suggestions for Authors

  1. In the introduction Section, the references in the second paragraph are missed.

Response:  The references in the second paragraph have been added in the revised manuscript as per suggestions on the page 2, line 54.

  1. In the introduction section, the authors must provide some relevant examples from literature to explain what has been the gap of the topic in the literature and correspondingly what is the novelty of current work respect to literature. In fact, the novelty of the work must be described better.

Response: The relevant literature has been added to the revised manuscript as per suggestions, on page 2, line 88-109. The novelty of the work has been explained in the revised manuscript as per suggestion. 

  1. The reaction pathway has to be mentioned in the manuscript.

Response: The reaction pathway has been added in the revised manuscript as per suggestions, on page 7, line 195-208. 

  1. The authors must better describe and clarify why they selected this catalyst and what is the role of CaO, Fe2O3 and feldspar in the reaction.

Response: The role of CaO, Fe2O3 and feldspar has been added and clarification on the selection of this catalyst has also been added to the updated introduction section of the revised manuscript, as per suggestions.

  1. In catalyst characterization section, some examples and comparisons with similar materials in the literature must be included.

 Response:  In the catalyst characterization section comparisons with similar materials in the literature has been included and discussed in the revised manuscript, as per suggestions from page 3-5.

  1. The characterization of the texture of the catalyst meaning N2 physisorption analysis is missed. The authors must discuss the surface area and porosity of the catalyst which is very important in the reaction.

 Response: As per suggestion, the surface area and porosity of the catalyst has been reported and discussed in the characterization section from page 4-5, line 145-162.

Reviewer 2 Report

The manuscript titled “Environmentally Friendly Nano-magnetic Catalyst 2 (CaO/Fe2O3/Feldspar) for Economic Production of Biodiesel 3 from Waste Oils” lakes in important information and discussion and should improve to be considered for publication:

 

1- The title is not adequate since no environmental and economic life cycle assessment was performed and discussed to conclude that these catalysts will allow an environmentally and economic production of biodiesel.

 

2- The characterization should also include XRD and SEM images including EDS of CaO-Fe2O3 before supported in the feldspar.

 

3- Catalytic results should include reusability tests, when heterogeneous catalysts are using  it is mandatory  to present the reusability tests since most of the already developed catalysts fails in stability during the catalytic cycles, so it is extremely important evaluate the catalyst stability and efficiency during several cycles, minimum 4-5 cycles. Please provide these results indicating the potential of magnetic separation during the cycles.

No comments.

Author Response

Response to Reviewer 2 Comments

The manuscript titled “Environmentally Friendly Nano-magnetic Catalyst 2 (CaO/Fe2O3/Feldspar) for Economic Production of Biodiesel 3 from Waste Oils” lakes in important information and discussion and should improve to be considered for publication:

Comments and Suggestions for Authors

  1. The title is not adequate since no environmental and economic life cycle assessment was performed and discussed to conclude that these catalysts will allow an environmentally and economic production of biodiesel.

Response:  As per suggestion, the title of the paper has been revised.

  1. The characterization should also include XRD and SEM images including EDS of CaO-Fe2O3 before supported in the feldspar.

Response: The XRD and SEM images and discussion including EDX of CaO-Fe2O3 before and after support on feldspar have been added to the revised manuscript. 

  1. Catalytic results should include reusability tests, when heterogeneous catalysts are using it is mandatory to present the reusability tests since most of the already developed catalysts fails in stability during the catalytic cycles, so it is extremely important evaluate the catalyst stability and efficiency during several cycles, minimum 4-5 cycles. Please provide these results indicating the potential of magnetic separation during the cycles.

Response: As per suggestion, a reusability study of the catalysts for all the oils has been performed and reported on page 8, line 226-224 of the revised manuscript.

 

Reviewer 3 Report

The paper shows the preparation of an efficient CaO/Fe2O3/Feldspar catalyst and its use in biodiesel synthesis from waste oils. The research of the present issue has been the subject of study by some workers in the past, and, it is still an active area of research. Results looks in some sense positive, but the current presentation requires some revisions so that I cannot recommend its acceptation in the present state.

Some of the points to be considered may be found below.

1. Introduction section: the more general knowledge is provided in Introduction section.  The initial four paragraphs are little interest and are recommended to be greatly shorted by consulting: Renewable and Sustainable Energy Reviews, 2023,171, 113017  

2. The literature review on the latest development on the magnetic solid catalysts is poor, and thus needs to be substantially enhanced. The recently published articles can be included, for example: Renewable Energy, 2020, 145,1709-1719; Fuel, 2018,220,248-256; Fuel 2021,283,118893.

3. The catalytically active species of the magnetic solid catalyst is not clearly presented in the paper.

4. The water content and acid value of the oil feedstocks should be given in the paper.

5. The reusability of the developed catalyst is an important factor, particularly from the view of long-term industrial applications. Therefore, the reusability study for the catalyst is suggested to be carried for the improvement of the scientific interest.

The paper shows the preparation of an efficient CaO/Fe2O3/Feldspar catalyst and its use in biodiesel synthesis from waste oils. The research of the present issue has been the subject of study by some workers in the past, and, it is still an active area of research. Results looks in some sense positive, but the current presentation requires some revisions so that I cannot recommend its acceptation in the present state.

Some of the points to be considered may be found below.

1. Introduction section: the more general knowledge is provided in Introduction section.  The initial four paragraphs are little interest and are recommended to be greatly shorted by consulting: Renewable and Sustainable Energy Reviews, 2023,171, 113017  

2. The literature review on the latest development on the magnetic solid catalysts is poor, and thus needs to be substantially enhanced. The recently published articles can be included, for example: Renewable Energy, 2020, 145,1709-1719; Fuel, 2018,220,248-256; Fuel 2021,283,118893.

3. The catalytically active species of the magnetic solid catalyst is not clearly presented in the paper.

4. The water content and acid value of the oil feedstocks should be given in the paper.

5. The reusability of the developed catalyst is an important factor, particularly from the view of long-term industrial applications. Therefore, the reusability study for the catalyst is suggested to be carried for the improvement of the scientific interest.

Author Response

Response to Reviewer 3 Comments

The paper shows the preparation of an efficient CaO/Fe2O3/Feldspar catalyst and its use in biodiesel synthesis from waste oils. The research of the present issue has been the subject of study by some workers in the past, and it is still an active area of research. Results looks in some sense positive, but the current presentation requires some revisions so that I cannot recommend its acceptation in the present state. Some of the points to be considered may be found below.

Comments and Suggestions for Authors

  1. Introduction section: the more general knowledge is provided in Introduction section. The initial four paragraphs are little interest and are recommended to be greatly shorted by consulting: Renewable and Sustainable Energy Reviews, 2023,171, 113017.

Response:  The Introduction section has been improved as per suggestions in the revised manuscript. The suggested reference has also been included.

  1. The literature review on the latest development on the magnetic solid catalysts is poor, and thus needs to be substantially enhanced. The recently published articles can be included, for example: Renewable Energy, 2020, 145,1709-1719; Fuel, 2018,220,248-256; Fuel 2021,283,118893.

 Response: A literature review on the latest developments on the magnetic solid catalysts has been added to the manuscript as per suggestions. Also, the suggested references have also been included. 

  1. The catalytically active species of the magnetic solid catalyst is not clearly presented in the paper.

Response: The detailed proposed mechanism of the reaction and the role of the catalysts has been presented and discussed in the revised manuscript on page 7, line 195-208.

  1. The water content and acid value of the oil feedstocks should be given in the paper.

 Response: The acid value of the oil feedstocks has been added in the methodology section.

  1. The reusability of the developed catalyst is an important factor, particularly from the view of long-term industrial applications. Therefore, the reusability study for the catalyst is suggested to be carried for the improvement of the scientific interest.

Response: As per suggestion, reusability studies of the catalysts for all the oils have been performed and reported on page 8, line 226-224 in the revised manuscript.

 

Round 2

Reviewer 1 Report

The manuscript has been improved properly and can be accepted.

Reviewer 2 Report

no comments

Reviewer 3 Report

My concerns are addressed properly, and this paper can be acceptable for publishing in this Journal.