@rosellenunez6363 if It is "brown" seems fine..try to suspend 100 mg in 200 ml of water. It has to be completely dispersed, not settled. Did you dry the product slowly, at low temperature?
Hello, after you add deionized water for the second time, how long should you wait to add H2O2 and what temperature should it be at? Another thing when I added the water the second time the solution changed from dark brown to black.. Any advice, as I am trying to get OG from the cashew seed by following these steps, but it is not working.
Friend, I followed all the steps according to the article but the solution did not turn yellow or brown when adding the DI water together with the hydrogen peroxide
@@FransYinho hi. Washing with HCl is meant to remove Mn, while water shall remove Cl and So4 ions. But the product probably got black before this, because you added H2O2 + water mixture very fast, then GO got reduced.
I have synthesized GO but final Ph after several time of washing and centrifuge is near 3 and doesn't change anymore, is it possible to use dialyse tube in distilled water to achieve ph near 7?
hi,, nice video in several articles i found that in modified hummers method we can add a 9:1 ratio of H2SO4 and H3PO4 mixture to the graphite. is this method a correct one with high purity and higher yield?
Hi, the one you mention Is calles Marcano Method. We havent tried it to avoid using H3PO4 (very corrosive), but they are reports for good quality GO. Our method leds to good repeteability, good oxidation degree, very good dispersability in water, high exfoliation degree.
After we got the GO solution, we put the solution in the centrifugue tubes, as.many as they fit in the centrífugue machine (6 in our case). We centrífugue, remove the supernatant, add HCl 5%, shake to resuspend some 2 min, centrífugue, and repeat three times with 5% HCl and other 3 with DI H2O. In the latest wash we recover powder with some remaining water in a porcelain capsule to dry in the oven at 60oC by 24 hr ñ.
Hi, I am doing GO synthesis but the final pH after washing with DI water is still acidic. Should the pH of GO be neutral and is there a pH requirement that must be achieved before the oven? thank you.
@@rosaliaimroatulmufidah7450 hello, yes, it is normal. The washings with DI water after HCl are intended to remove Cl ions. But pH of a GO suspensión is around 3-5, normally. Best regards
Enough to do an homogenous mixture. Nevertheless, this time shall influence the final amount of carboxyl groups, so if You have time You could try diferent times at this stage before KmNO4 addition
Thanks for your vedio, can you tell me the weight of graphite you used for 6 grams of KMNO4 ? And why you didnt used NaNO3 as mentioned in hummers method ? Another thing can i do vacume filteration instead of centerfugation ? I really want to read your paper can you send me the link please
You can check the paper here (www.researchgate.net/publication/270591983_Graphene_oxide_powders_with_different_oxidation_degree_prepared_by_synthesis_variations_of_the_Hummers_method) , if you can not have access send me an email ID to send you the PDF. About NaNO3, yes we use it. About vacuum filtering, you can use it but filter gets clogged easily and you will loose a lot of material. About the weight of KMnO4/graphite is proportional, for 6 g of KMnO4 you will need 2 g of graphite and 1 g of NaNO3, 46 mL H2SO4.
@@cigmmad hi thank you for the link and reply. I wonder why i cant get this yellow productvof GO at the end i have done all the steps as in the article at beginning everything is going well i have a nice brown colour but when heat the solution to 90o it turn to very dark brown after adding H2O2 it still dark green and when i finish all steps after drying i have ablack ppt ! Am rellay tired with repeating the reaction but still didnt git finall result as yellow ppt can you help me with please
@@Nisar2641. The dried product has to be brown like coffee not yellow. 2. If the product turns black after drying you are heating too much. Temperature must be around 50-60 oC degree. Drying must take some 12-24 hrs. The definitive quality test is that you suspend the material in water (some 0.5 mg/mL water) and no settling must happen in some hours. Let me know if this was helpful
Thanks its clear now just one more question when i do washing with water i have to wash untill reach pH 6 right ? Its compulsory for the productvto be neutral?? Because i have added like 200 ml of doubled distilled water for washing till i got the pH 6 and beacuse i didnt had crnterfuge i did vaccume filteration but here i have the problem with type of filters i wonder which is best type filterpaper to use if you know please
@Nisar264 No strict need of pH 6, just rinse 3 times with HCl 5% and then 3 times with DI water. To rinse each time use the same Volume you have for the synthesis: H2SO4, H2O, H2O2+H2O = TOTAL VOLUME = 1 Volume HCl = 1 Volume H2O, I hope Is clear, otherwise Let me know plz
Plz i did the synthesis based on modified hummers using graphite, H2SO4 and KMnO4 the solution became black at the end and after centrifugation I filtered the solution and i got something like powder and it's black before even i let it in the oven. where is the mistake ?
Hello. We use a "toaster" oven because we can control the temperature around 50oC si GO do not decompose, that is why it is si slow. In a microwave You have to test if temperature do not rise 50 oC. Of course is better a laboratory convection oven.
Ok. thank you sir. What is the purpose of using NaNO3 in the initial chemical reaction? Is this possible to done this experiment without using sodium nitrate?
Hello @@priyankas4914 well, there are several routes for GO synthesis. For example, there is one based on sulfuric and fosforic acid which not employ NaNO3, this is call the Marcano process. The purpose of NaNO3 is to separate the graphite layers and allow access to KMnO4 to oxidize the double bonds.
Hi, thanks for the good videos. May i know, why you wash with HCl 5% solution? i mean i already make GO until the centrifuge steps. But my GO solution at 3 (pH), is with HCl solution can increase the pH of my GO solution? Or it will decrease the pH of my GO solution? Need the answer a.s.a.p if u don't mind hehe :)
@@cigmmad thanks for the answer but i'm already used DI water and centrifuge before i use HCl solution. Is it ok? Let me know what matters if it is reversed🙏
@@28_fransiskusjulioalfonsos8 well, with DI You won't be able yo remove most of Mn ions. If You want to try it and later compare with HCl rinsing and do some.elemental analysis to see ir only water removes Mn let me know.
The solution is a commercial antifreeze for cars, it is used to reach 98ºC without evaporation, thus we recommend the antifreeze with the highest possible boiling point. However, because of the generated fumes, it has to be done in fumehood to avoid health issues. Another option is to use a sand or an oil bath to safely reach 98ºC, it is question which one is easier to control; for oil is usually very dirty. I hope it is useful, let us know if you do the experiment and how it works for you.
Hi, we got about 2 g of GO for each batch. It could be more but our centrifugation machine has only 4000 rpm so the lighter fractions (less sheet, more exfoliated GO) are lost.
on peut l'utilise apres le netoyage avec HCl 0.5 et apres H2O pour dehydrater le graphene oxide avant le mise au fourne, mais on peut avoir un peu de reduction de oxygene groups @@benedictekyamba
We said "three volumes" because if the final volumen of the GO solution is, lets Say, 200 ml, we pour it in 15 mL centrufugue tubes and wash it three times
Hi. No, we don't add water at that moment (30 min) but after the periods at 5 oC and 30 oC, the water is added and temperature is risen to 98oC. You added water to a highly reactive H2SO4 and KMnO4 mixture, that is why You get the violent reaction.
@@wedadali9359yes, there are several and they depend on the level of reduction you want to achieve. For example you can use green reduction agents such as ascorbic acid, glucose, antioxidant additives (we can discuss options), or use hydrazine or NaBH4 if you have a lab with good safety as they are toxic or reactive.
ok. actually I did that by NaBH4 , but the structure was not good , I mean I didn't get single layer. I have also question please, I want to know about temp. why should control it less than 10C,and then with rGO should increase it. Thank you
Applications range from energy storage, waste water treatment, water desalination, hydrogen generation, coatings for protection or electromagnetic management, drug delivery, sensors, composites and additives for plastics, between many more.
la machine a rotation n'a pas de scale de vitesse, mais on fixe la vitesse tel que un vortex aparait et tout se melange bien.(pardon pour mon Francais)
@@cigmmad can you tell me it is a hummer method or modified one as research paper ( you have mentioned ) used the " term variation of hummer method" ? But not modified clearly
@@ridarida3154 we said "variation" because the reactants addition, how the H2O2-H2O mixture is added, how the material is washed are modifications of the Hummers report. You can check our paper here: 10.1016/j.matchemphys.2015.01.005
Friend, I followed all the steps according to the article but the solution did not turn yellow or brown when adding the DI water together with the hydrogen peroxide
I suppose your Solution Is black, yes? It happens when the KMnO4 is added very fast or if H2O AND H2O2 Is added suddenly. The color shall be greenish-yellowish, not net Green or Yellow
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Fast addition or KMnO4 during oxidation or if H2O2 and water at ehe end may reduce GO and turn black the suspension
@rosellenunez6363 if It is "brown" seems fine..try to suspend 100 mg in 200 ml of water. It has to be completely dispersed, not settled. Did you dry the product slowly, at low temperature?
Hello, after you add deionized water for the second time, how long should you wait to add H2O2 and what temperature should it be at?
Another thing when I added the water the second time the solution changed from dark brown to black..
Any advice, as I am trying to get OG from the cashew seed by following these steps, but it is not working.
Friend, I followed all the steps according to the article but the solution did not turn yellow or brown when adding the DI water together with the hydrogen peroxide
Why after washing with water and HCl I get a black solution instead of brown?
@@FransYinho hi. Washing with HCl is meant to remove Mn, while water shall remove Cl and So4 ions. But the product probably got black before this, because you added H2O2 + water mixture very fast, then GO got reduced.
I have synthesized GO but final Ph after several time of washing and centrifuge is near 3 and doesn't change anymore, is it possible to use dialyse tube in distilled water to achieve ph near 7?
You can stop at pH 3, GO is acidic in solution, if you can dialyze let me know the results!
While adding KMnO4 to the graphite mixture, which color should be obtained? In my case, it is a dark green color. Is this ok or not?
Yes, is the right color. Congrats!
hi,, nice video in several articles i found that in modified hummers method we can add a 9:1 ratio of H2SO4 and H3PO4 mixture to the graphite. is this method a correct one with high purity and higher yield?
Hi, the one you mention Is calles Marcano Method. We havent tried it to avoid using H3PO4 (very corrosive), but they are reports for good quality GO. Our method leds to good repeteability, good oxidation degree, very good dispersability in water, high exfoliation degree.
Also plz explain the centrifuge process in you videos of GO and washing. If you don't mind thank .
After we got the GO solution, we put the solution in the centrifugue tubes, as.many as they fit in the centrífugue machine (6 in our case). We centrífugue, remove the supernatant, add HCl 5%, shake to resuspend some 2 min, centrífugue, and repeat three times with 5% HCl and other 3 with DI H2O. In the latest wash we recover powder with some remaining water in a porcelain capsule to dry in the oven at 60oC by 24 hr ñ.
Hi, I am doing GO synthesis but the final pH after washing with DI water is still acidic. Should the pH of GO be neutral and is there a pH requirement that must be achieved before the oven? thank you.
@@rosaliaimroatulmufidah7450 hello, yes, it is normal. The washings with DI water after HCl are intended to remove Cl ions. But pH of a GO suspensión is around 3-5, normally. Best regards
Very demonstration
Can you tell about DI water addition after 30 mint stirring at 35 °C. We should add is slowly and after cooling of mixture ?
As someone commented that it got fumes out in laboratory.
Because if you add it fast the reaction Will be fast and GO will became reduced
@@cigmmad we should add it in when flask in ice bath or in room temperature water (35°c )?
Hi there,
Before adding KMnO4 how many minutes should we stirr sulphuric acid with sodium nitrate and graphite powder?
Enough to do an homogenous mixture. Nevertheless, this time shall influence the final amount of carboxyl groups, so if You have time You could try diferent times at this stage before KmNO4 addition
@@cigmmad alright, thanks!
Plz tell if dark green color appears, what should we do?
That is a sign you have good reaction. Keep it until it finishes
Thanks for your vedio, can you tell me the weight of graphite you used for 6 grams of KMNO4 ? And why you didnt used NaNO3 as mentioned in hummers method ? Another thing can i do vacume filteration instead of centerfugation ?
I really want to read your paper can you send me the link please
You can check the paper here (www.researchgate.net/publication/270591983_Graphene_oxide_powders_with_different_oxidation_degree_prepared_by_synthesis_variations_of_the_Hummers_method) , if you can not have access send me an email ID to send you the PDF. About NaNO3, yes we use it. About vacuum filtering, you can use it but filter gets clogged easily and you will loose a lot of material. About the weight of KMnO4/graphite is proportional, for 6 g of KMnO4 you will need 2 g of graphite and 1 g of NaNO3, 46 mL H2SO4.
@@cigmmad hi thank you for the link and reply. I wonder why i cant get this yellow productvof GO at the end i have done all the steps as in the article at beginning everything is going well i have a nice brown colour but when heat the solution to 90o it turn to very dark brown after adding H2O2 it still dark green and when i finish all steps after drying i have ablack ppt ! Am rellay tired with repeating the reaction but still didnt git finall result as yellow ppt can you help me with please
@@Nisar2641. The dried product has to be brown like coffee not yellow.
2. If the product turns black after drying you are heating too much. Temperature must be around 50-60 oC degree. Drying must take some 12-24 hrs.
The definitive quality test is that you suspend the material in water (some 0.5 mg/mL water) and no settling must happen in some hours. Let me know if this was helpful
Thanks its clear now just one more question when i do washing with water i have to wash untill reach pH 6 right ? Its compulsory for the productvto be neutral?? Because i have added like 200 ml of doubled distilled water for washing till i got the pH 6 and beacuse i didnt had crnterfuge i did vaccume filteration but here i have the problem with type of filters i wonder which is best type filterpaper to use if you know please
@Nisar264 No strict need of pH 6, just rinse 3 times with HCl 5% and then 3 times with DI water. To rinse each time use the same Volume you have for the synthesis: H2SO4, H2O, H2O2+H2O = TOTAL VOLUME = 1 Volume HCl = 1 Volume H2O, I hope Is clear, otherwise Let me know plz
Plz i did the synthesis based on modified hummers using graphite, H2SO4 and KMnO4 the solution became black at the end and after centrifugation I filtered the solution and i got something like powder and it's black before even i let it in the oven. where is the mistake ?
Fast addition or KMnO4 during oxidation or if H2O2 and water at ehe end may reduce GO and turn black the suspension
Can we use hot water bath temperature maintained at 98 ° C instead of antifreeze liquid or oil bath??
Yes but it will be hard to avoid boiling and evaporation. You Will have to be adding extra water
Which oven is used for drying process? Microwave oven or hot oven? Is this possible to dry in 4 or 6hours using this oven?
Hello. We use a "toaster" oven because we can control the temperature around 50oC si GO do not decompose, that is why it is si slow. In a microwave You have to test if temperature do not rise 50 oC. Of course is better a laboratory convection oven.
Ok. thank you sir. What is the purpose of using NaNO3 in the initial chemical reaction? Is this possible to done this experiment without using sodium nitrate?
Hello @@priyankas4914 well, there are several routes for GO synthesis. For example, there is one based on sulfuric and fosforic acid which not employ NaNO3, this is call the Marcano process. The purpose of NaNO3 is to separate the graphite layers and allow access to KMnO4 to oxidize the double bonds.
Hi, I want to ask how many ml is needed to wash the sample with 5% HCL?
Three Volumes. Some 150 ml each one.
Hi, thanks for the good videos. May i know, why you wash with HCl 5% solution? i mean i already make GO until the centrifuge steps. But my GO solution at 3 (pH), is with HCl solution can increase the pH of my GO solution? Or it will decrease the pH of my GO solution? Need the answer a.s.a.p if u don't mind hehe :)
It is because You need to remove Mn ions and thereafter You rinse with DI water to remove Cl ions
@@cigmmad thanks for the answer but i'm already used DI water and centrifuge before i use HCl solution. Is it ok? Let me know what matters if it is reversed🙏
@@28_fransiskusjulioalfonsos8 well, with DI You won't be able yo remove most of Mn ions. If You want to try it and later compare with HCl rinsing and do some.elemental analysis to see ir only water removes Mn let me know.
@@cigmmad thanks mate, i will do that later. hope u have a great day!
@@28_fransiskusjulioalfonsos8 good luck!
what is the antifreeze solution? and why is it added?
The solution is a commercial antifreeze for cars, it is used to reach 98ºC without evaporation, thus we recommend the antifreeze with the highest possible boiling point. However, because of the generated fumes, it has to be done in fumehood to avoid health issues. Another option is to use a sand or an oil bath to safely reach 98ºC, it is question which one is easier to control; for oil is usually very dirty. I hope it is useful, let us know if you do the experiment and how it works for you.
Plz reply i want to know time bcz lots of ppl around me said it take 3-5 days to prepare Go. Is it true?
It takes a couple of days, synthesis, washing, drying
what concentration of H2SO4 you use??
It is concentrated H2SO4, directly from the bottle, reactive or ACS grade.
lets us know if you get GO with this video!
@@cigmmad how can i contact you, i have a few question
@@TyNguyen-yh4fe send your email .ID, I willl contact you
May I ask what's your % yield for this? thank you!
Hi, we got about 2 g of GO for each batch. It could be more but our centrifugation machine has only 4000 rpm so the lighter fractions (less sheet, more exfoliated GO) are lost.
Sure, send the steps.
À la place de l'eau peut-on utilisé de l'éthanol ?
No, on ne peut-pas parce-que l'ethanol i reaction fortement avec le acid sulphurique.
Quand peut on utilisé l'éthanol
on peut l'utilise apres le netoyage avec HCl 0.5 et apres H2O pour dehydrater le graphene oxide avant le mise au fourne, mais on peut avoir un peu de reduction de oxygene groups @@benedictekyamba
Please mention volume of deionized water you have used in centrifugation process.
We said "three volumes" because if the final volumen of the GO solution is, lets Say, 200 ml, we pour it in 15 mL centrufugue tubes and wash it three times
@@cigmmad ok got it
We use three volumes considering the final volumen of the GO solution. We use 15 mL centrifugation tubes to pour Go
@@nabaaanoor_ i hope it is useful and you can share your experience with us
after 30 min, you added DI water to solution?
when i did that the reaction was excited and the ash get out from flask to all lab
Hi. No, we don't add water at that moment (30 min) but after the periods at 5 oC and 30 oC, the water is added and temperature is risen to 98oC. You added water to a highly reactive H2SO4 and KMnO4 mixture, that is why You get the violent reaction.
ok thank you
@@cigmmad
and please is there any achieved method to get reduced graphene oxide
@@wedadali9359yes, there are several and they depend on the level of reduction you want to achieve. For example you can use green reduction agents such as ascorbic acid, glucose, antioxidant additives (we can discuss options), or use hydrazine or NaBH4 if you have a lab with good safety as they are toxic or reactive.
ok. actually I did that by NaBH4 , but the structure was not good , I mean I didn't get single layer.
I have also question please, I want to know about temp. why should control it less than 10C,and then with rGO should increase it.
Thank you
What is graphene oxide used for?
Applications range from energy storage, waste water treatment, water desalination, hydrogen generation, coatings for protection or electromagnetic management, drug delivery, sensors, composites and additives for plastics, between many more.
Quelle est la vitesse de rotation utilisée
la machine a rotation n'a pas de scale de vitesse, mais on fixe la vitesse tel que un vortex aparait et tout se melange bien.(pardon pour mon Francais)
How much time ( days ) taken by your experiment ?
Two days, synthesis one day, washing and drying second day.
@@cigmmad can you tell me it is a hummer method or modified one as research paper ( you have mentioned ) used the " term variation of hummer method" ? But not modified clearly
@@ridarida3154 we said "variation" because the reactants addition, how the H2O2-H2O mixture is added, how the material is washed are modifications of the Hummers report. You can check our paper here: 10.1016/j.matchemphys.2015.01.005
@@cigmmad ok thank you ✨stay blessed
Friend, I followed all the steps according to the article but the solution did not turn yellow or brown when adding the DI water together with the hydrogen peroxide
I suppose your Solution Is black, yes? It happens when the KMnO4 is added very fast or if H2O AND H2O2 Is added suddenly. The color shall be greenish-yellowish, not net Green or Yellow
I really made these mistakes, thank you, I will repeat the synthesis@@cigmmad
@@Flokyavatar ok, let me know if it worked!
@@cigmmadmine is too yellow, what do you think is my mistake?
@@rosellenunez6363 does It have sedimented material? Otherwise It could be fine. After rinsing and drying what color It has?