Your solution seems fine bye the color.. Usually when it became black means that is reduced because fast addition of H2o2. Question, material is well suspended in water? If so, everything is fine.

@@felipecaballero4946Thank you for the reply....& plzz answer the other question as well.... when to suspend the material in water???is it after drying or after addition of H2O2??

@@asiyabasit7752 yes, after drying. I mean the final product.

When You don't recover more material. If GO is very well oxidized It may happen some material would not settle if your centrífugue speed is not high enough. With a 4000 rpm centrífugue we use some 5 min to avoid solution heating and reduction, but suspended, well exfoliared material is Lost for us. If you have a refrigerated centrífugue with higher speed, sequential separation by degree of exfoliation is then possible.

@@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.

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

You can stop at pH 3, GO is acidic in solution, if you can dialyze let me know the results!

That is a sign you have good reaction. Keep it until it finishes

@@estronciopirito7489 hola, si se puede, de hecho hemos usado alguna vez una fuente de esas. Saludos y suerte.

@@cigmmad Muchas gracias.

@@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

Three Volumes. Some 150 ml each one.

Hi, Gem Ram cost about 70-80 K USD.

Well, Mn would induce other effects, such as catalytic Activity, so depends

@@cigmmad I am going to try using it in electrochemistry, primarily for enhancing anodes in batteries in experiments. I wonder if there is any other way of getting rid of Mn.

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.

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 )?

It takes a couple of days, synthesis, washing, drying

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

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.

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.

Fast addition or KMnO4 during oxidation or if H2O2 and water at ehe end may reduce GO and turn black the suspension

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

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

@@Toquedefé12 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?

Yes, is the right color. Congrats!

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)

Hola, perdona la tardanza en contestarte. Es una pieza hecha a la medida para sujetar el sustrato. Son dos placas paralelas unidas por un tornillo que lo detienen. Tiene una ranura de 1 mm para que el vidrio entre y no se parta al apretar el tornillo. La pieza es de aluminio pero puede ser de plastico sin problema, ya que no se sumerge.

​@@cigmmad No se preocupe, yo estaba tratando de construir una máquina que también sujeta un sustrato de vidrio, solo me falta esa pieza y pues no he encontrado nada, ¿hay alguna forma saber más sobre las medidas con las que la construyeron ustedes, los materiales que usaron y así? he buscado por internet algo parecido, pero no encuentro nada

Hola @@ravtepdav la pieza se hizo de aluminio y de ancho tiene lo que un portaobjetos, o sea 1 pulgada, se diseño para que sostuviera el vidrio en una media pulgada para que no se caiga. La mandamos a hacer el un torno, pero si te sirve la idea, con una pinza cualquiera que sostenga firmemente el vidrio y que se sujete firmemente al brazo que baja, sin vibrar, te es suficiente

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

I am sorry for that, it was recorded live, on line. If interested on the subject you could give me a contact and I can try yo reach the lecturer for you.

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!

❤

Hola. en realidad este aparato que presento es comercial, se usa para chapado de piezas de joyeria. La esponja permite que haya contacto del liquido en todos los resquicios de la pieza. Claro que se puede hacer sumergiendo la pieza en la solucion, pero en ese caso si se requiere un volumen mucho mayor de la solucion y calcular las concentraciones del metal en disolucion por ejemplo. Uno puede hacer sus propios baños basandose en literatura, pero se requiere comprar el reactivo y demas. En este sistema no hay necesidad porque la solucion viene preparada, incluyendo los aditivos que pueda requerir para adherencia, etc. Para chapar el alambre que les presente se gasta menos de 1 mL de la solucion que viene en el botecito.

Yo uso electrodo inerte con alambre de platino y me trabaja excelente

Si, @@carlospereda100 el electrodo de platino inerte es mucho mejor, la alternativa con rodio era por la disponibilidad.

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.

Hola. Podrías ampliar tu comentario?

@@cigmmad con gusto, yo arme placas peltier por 380 pesos, bueno el circuito completo con 600 pesos lo armo, me dio risa cuanto gastaste solo en un experimento, yo lo tengo dentro de una consola de videojuegos como frigobar, bueno cada quien hace lo que puede, saludos y animo con los estudios.

La humanidad desperdicia mucho, si no es que todo, para pisar la misma piedra una y otra vez.

@@cristianca7792 si, tienes razón, por no ser experto o no tener las habilidades para algunas cosas se "redescubre el hilo negro", pero por un lado que bien que tengas un sistema más eficiente y más barato y por otro te agradezco el exhorto a seguir con lo que hacemos. Saludos!

@@cigmmad las habilidades se logran viviendo, la experiencia con el tiempo, tal vez sea pretencioso pero tu video salio por sugerencia y canales de consumo capitalista hay por todos lados, no me lo tomes a mal estoy en esta red social para tener puntos de vista de otras personas, incluyendo criticas, con eso resolvi mi generador de fision del tamaño de una mochila y muchos inventos mas, animo amigo, solo recuerda que el poder corrompe el alma y desde hay, ya estamos mal.

Que bueno que te haya gustado. Esperamos que encuentres más material de tu agrado en este canal.

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

Yes but it will be hard to avoid boiling and evaporation. You Will have to be adding extra water

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!