Generally, the work topic is important with objective of studying the influence of adding nanoparticles into blended fuel on engine performance. Here different nanoparticles were used to explore the effect of particle origin. However, Authors didn't properly formulate the study objective to highlight its novelties. Here novelties may only be related to the optimization process of biodiesel production with unclear novelties related to engine experiments. In my opinion, the current version has many comments that should be followed: 1- Please try to type highlights in generic form to provide the significant complete meaning; it is not to meet requirements but also to focus on most important information in the manuscript. For example (i) highlight #1: didn't provide better than which; it may be the best, (ii) highlight #2: didn't indicate which carbon emissions are studied, and (iii) highlight #4 may be improved like to be: Palm biodiesel blends with additives of nanoparticles improved engine performance. 2- The abstract should provide briefly the range of studied parameters. Hence the provided results and conclusions would reflect the recommended ranges of these parameters. It would be important to provide general conclusion by the end of the abstract; for example Highlight #4. 3- In line 98, word "to use" should be "by use of" 4- In line 102 the "Response surface methodology" was introduced as an optimization method to statistically find the optimum operating conditions of transesterification process. It will be valuable to provide the concepts of this optimization method briefly. In this regarded, main results from the reviewed works are needed to confirm accuracy statistical method to identify the optimum production conditions. 5- In line 112, Nitrogen oxides were symbolized as NOx while symbolized in Nomenclature as NO; please unify all symbols. 6- In line 124, the word respectively can be deleted, as there is no order of actions to be followed. 7- In the introduction part, it was more valuable to review works related to the studied biodiesel "Palm Biodiesel" with and without nano-additives. Then to formulate the objective of the study. 8- The study objective was formulated improper without good connection with the reviewed works; the current objective stated only the optimization of biodiesel production and its stability (which was not reviewed in the introduction). 9- Scientifically, I'm not sure that, Authors should not preheat palm oil during biodiesel production with the help of ultrasonicator; as ultrasonic pulsation already heat the oil to approach even 70°C. If it is correct, then the effect of reaction temperature shouldn't be considered in the optimization process. In this regard, review related to ultrasonic assisted transesterification was not cited in the introduction. 10- In line 152, abbreviation FFA was neither stated in the text nor in the nomenclature. In this regard it is important to point out to the limit of FFA at which esterification process should be used before transesterification to ensure that for palm oil with FFA 2.32 this step is mandatory. After line 153, the mentioned equations can be placed; it is not common to state equation in the next page of their first referred location in the text; and so other equations stated in the manuscript. 11- In line 162 "KOH catalyst is more reactive than other alkali catalysts" it is common to compare item by its equivalent item as "basis catalyst vs alali catalyst" and "KOH vs NaOH"; please notice that. Here the word "continuously" in line 164 may leads reader to think that washing performed in a continuously flowing water; please remove this ambiguity. 12- It will be valuable if the measurement of FAME using Agilent GC was performed following standard test method. Here it is possible to combine Tables 1 and 2 in a single Table. 13- Please reconsider sentence in line 191 to remove ambiguity in its language structure. 14- Please reconsider long sentences as that in lines 196-200; where brackets are not needed. 15- In item 2.3, the structure of nanoparticle was not stated nor the size range of these nanoparticles. Hence, it seems from Table 4 that nanoadditives have minor effect on viscosity and heating value; please discuss these measurements. In this part, Figure 2 was not mentioned in the text; please correct this issue. In this study, the portion of nanoparticles was not identified which should be selected according to previous work or as recommended by other studies. 16- In line 231, B10 should be D100. Please provide model number for applied instrumentations or provide its measuring range as AVL emission analyzer. The engine experimental program was not stated; here why Authors selected speed from 1050 to 2300 rpm; it is common to has best efficiency at engine rated conditions which may be at engine speed of 2400 rpm or not. Moreover, there is no reasons why Authors selected B30 rather than most common of B20. Finally, uncertainty analysis should be provided. 17- In item 3, it is important to compare the received results with those cited in the literature. It was important to discuss the effect of adding nanoparticles in the physicochemical properties of the blended fuel and to predict how this could affect engine combustion. 18- Deep discussion of received results is needed to explore the deviation in results found in Figure 6 and others related to engine experiments. Again, it is important to strengthen the received results by confirmed discussion about effect of nanoparticles on delay period, combustion quality, and so on. 19- Effect of engine speed provides two opposing effects (i) increase in turbulence and so improve in fuel-air mixing and (ii) increase in friction power. If Authors agree, please reconsider sentence in line 310. Sentence in line 323 may need justification; in fact, it opposes discussion in line 325. The CO emissions from diesel engine depends not only on the improper mixing but also on dissociation of CO2, temperature and oxygen concentration of the reaction. The addition of nanoparticles provides further reduction in CO but not due to oxygen concentration, here it is due to the catalytic effect of nanoparticles. Please use proper discussion of results from engine experiments to (i) state comparison results of B30 compared to those of base fuel, then (ii) the effect of nanoparticles to keep reader solicitude. 20- Please try to connect the study conclusion with its objective. It is important here to state conclusion related to blended fuel stability.