The aim of this study was to reuse these waste acids efficiently. 2.1. reactionmethod The basic chemical reaction involved in the Hummers' method is the oxidation of graphite, introducing molecules of oxygen to the pure carbon graphene. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts. Synthesis of Graphene Oxide Graphene oxide was prepared using the simplified Hummers’ method. The Hummers method is the most commonly used method to prepare graphene oxide (GO). Compared to Hummers’ method, the Fenton reagent has similar exfoliation efficiency, but due to the Fenton reagent’s preference to react with the edges of graphite, the chemical reduction can lead to the formation of less defective reduced graphene oxides. systematic study of the physical principle of the method, by-products and the mechanism of reduction process would be a key for realizing large-scale production of GO. This employed two different chemical reduction methods, and one effective combination of the two. Graphite oxide (250 mg) was placed in a 100 mL reaction ask with a magnetic stirring bar, and iron powder (50 mg) was added. It shows that in Hummers method, a typical material ratio of 1:3.5:23 and reaction time of about 2 hours are selected, which leads to low yield and toxic byproduct. Department of Chemistry and Materials,Naval University of Engineering, Wuhan 430033,China; 2. Synthesis of Graphene Oxide Graphene oxide was prepared using the simplified Hummers’ method. In this paper, using the Hummers method, to prepare oxidized graphite and graphene , to optimize the conditions of the preparation of graphite oxide. equiv. The reaction has been performed in a 9:1 (by volume) mixture of H2SO4/H3PO4. Jun 20, 2013: Researchers develop a method for the rapid preparation of graphene oxide (Nanowerk News) The most common method for synthesizing GO is the Hummers' method (oxidation with KMnO 4 and NaNO 3 in concentrated H 2 SO 4), which requires a long reaction time and large amounts of reagents.In their research, Assistant Professor Yuta Nishina and his team … The Hummers method has some advantages compared to the method of Brodie and Staudenmaier. The reaction equations of Hummers and two improved Hummers were shown in Figure 4. In this study, reaction calorimetry is used to determine the heat of solution and … 2.25 g of KMnO 4 was added while simultaneously heating to 50 °C while continuously stirring. The exfoliation of graphite to graphene can be realized either physically or chemically [1] . The influences of the content of graphite,the time under low reaction temperature,the content of sodium nitrate, the content of potassium permanganate and the way of adding water under high reaction temperature on the structure and resistivity of GO were investigated … Preparation of graphite oxide by a modified version Hummers method GO was prepared from the commercial graphite using a modified Hummers’ method (GO-H) [6, 20, 23]. Parameters such as reaction time, reaction temperature, and amount of concentration were varied to study the degree of oxidation of graphite to graphene oxide. At the same time, due to the reaction temperature of 70 °C, GO was also reduced at a higher reaction temperature. Hummers method has attracted a large attention because of its high efficiency and satisfying reaction safety. The first methodology, named A, is the Hummers method composed of 5 stages, as described in the experimental part. The overall unzipping process involves the same three steps as in the course of GO production from graphite by the Hummers and modified Hummers methods: intercalation, oxidation, and exfoliation. Graphene Oxide can be synthesized by using Hummer’s method provided here, It needs to be done by using all lab safely precautions. The efficiency of the synthetic method under two hydrothermal conditions was examined for graphite oxide produced by Hummers and Hofmann oxidation routes. three (B, C, D) different modified versions of the Hummers method-assisted MWR compared with the conventional graphite oxide (cGO) sample obtained by Hummers method (A). With two kinds of reductors, glucose and hydrazine hydrate, reduction graphite oxide, and dropped silver ions in the process of reduction. Recent applications of … Compared to Hummers’ method, the Fenton reagent has similar exfoliation efficiency, but due to the Fenton reagent’s preference to react with the edges of graphite, the chemical reduction can lead to the formation of less defective reduced graphene oxides. developed a method for the synthesis of GO [23]. Next KMnO 4 is added slowly by maintaining the required temperature. been proposed since 1855; the most famous one is Hummers' method8 which uses potassium permanganate (KMnO 4)and sodium nitrate (NaNO 3). Hummers’ method uses a combination of potassium permanganate and sulphuric acid. The effects of ultrasonication time from 1 to 2 h and Zn mass ranging from 8 to 24 g as reducing agent were observed in detail for … TEPA was selected among several other amines because of its low cost, low toxicity and the reasonable number of eNH2 groups that can improve the adsorption of CO2. In a typical preparation, 5 g NaNO 3 was added to cold H 2 SO 4 solution (230 ml, 95-98%) prepared at 7 °C in an ice bath and stirred by a magnetic stirrer for 5 minutes. It consists of carrying out a reaction of graphite powder with KMnO 4 and NaNO 3 in concentrated H 2 SO 4. This method makes use of the Hummers’ reagents with additional amounts of NaNO3 and KMnO4. method and modified Hummers method [23, 24]. Though permanganate is a commonly used oxidant (e.g. Graphite, Sulphuric Acid, Potassium Permanganate (KMnO4), Hydrogen Peroxide (H2O2), Water, Beaker, Measuring Cylinder, Magnetic Stirrer. The oxidizing process of bio-char to GO was noticeably faster compared with the Hummers method using graphite powder. More recently, Marcano et. However, many waste acids remain in the raw reaction mixture after the completion of this reaction. 2.1.1.Modified hummers' method The precursor for the synthesis of rGO is graphite powder. Hummers method has attracted a large attention because of its high efficiency and satisfying reaction safety. Authors: Graphite oxide was successfully synthesized from graphite powder using the modified Hummers method*. SO 6. pp. Both methods involve the oxidation of graphite but differ in mineral acids, oxidizing agents, preparation time and type of washing/drying processes. The GTO prepared by this method was named as HGTO. Experimental Method 2.1. three (B, C, D) different modified versions of the Hummers method-assisted MWR compared with the conventional graphite oxide (cGO) sample obtained by Hummers method (A). The most important and widely used method for the synthesis of graphite oxide is the one developed by Hummers and Offeman in 1958 (Hummers' method) [28, 29]. On the other hand, the Improved Hummers method used in … Graphene oxide was prepared by improved Hummers method. Why In Modified Method , they waching GO with HCL in centerfusion ? any one can help please However, the challenge is to synthesize graphene in a bulk quantity. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts. Technologies dependent on regenerable sorbents in the 300 ◦C –500 ◦C (intermediate temperature) range are used for improved process integration. The top down method includes hummers method and modified hummers method, which is the most common method of synthesis of graphene oxide. However, it still has a few drawbacks. Hummers and Offemann presented an optimized, rapid, safe method of graphite oxidation, whereby GO is obtained via treatment of graphite by strong oxidizing agents. For instance, the oxidation procedure releases toxic gasses such as NO 2 and N 2 O 4 and also the residual Na + and ions are difficult to be removed from the waste water formed from the processes of synthesizing and purifying GO. equiv. Graphene is potentially attractive for electrochemical energy storage devices but whether it will lead to real technological progress is still unclear. Then the mixture was heated in a microwave oven (2.4 GHz, 800 W) for 0.5 h, together with continuously grinding and then naturally cooled to room temperature. Dreyer et al. The temperature of the mixture is maintained below 5 ° C. The suspension is then reacted in an ice bath and stirred before again stirred in a 40 ° C water bath. [ ] believed that the active species was Mn 2 O 7. e following equation gives the reaction between KMnO 4 and H 2 SO 4: KMnO 4 +3H 2 SO 4 K + + MnO + 3 … The Hummers method is frequently used as a universal method for the formation of GO from the precursor which is the graphite. It consists of carrying out a reaction of graphite powder with KMnO. In 2010, Tour et al.9,10 reported an improvement on Hummers' method through excluding NaNO 3 to prevent the generation of toxic gases, using ice instead of liquid water to prevent the high temperature rise, In this method powdered flake of graphite is mixed with NaNo 3 and H 2 SO 4. ), NaNO 3 (1 g, 0.5 wt. An Innovative Synthesis of Graphene oxide by hummer's method (PDF) An Innovative Synthesis of Graphene oxide by hummer's method | ehsan ezzatpour ghadim - Academia.edu Academia.edu no longer supports Internet Explorer. In this paper, Hummers’ method uses a combination of potassium permanganate and sulphuric acid. Concentrated H2SO4 (360 mL) was added to a mixture of graphite (7.5 g) and Graphite oxide was prepared by modified Hummers’ method 47 and functionalized with azide with reaction of GO with sodium azide in DMF for 48 h to obtain GO-N 3 48. Materials 3 g flake graphite (44 µm, 99.8% carbon, Ash colour from Asbury Carbon, New Jersey, USA) was added into 400 mL solution of concentrated H 2 SO 4 (98%, BDH) in 1000 mL conical flask. Either sodium chlorate in nitric acid (similar to Brodie's method) or potassium permanganate in sulfuric acid (similar to Hummers’ method) treatment are possible; however, reaction conditions must be controlled. Graphite Oxide (GO) was prepared from flake graphite through liquid oxidation based on Hummers method. All are assumptions only ... Till exact mechanism not yet found... Here we reported an improved NaNO 3 -free Hummers method by partly replacing KMnO 4 with K 2 FeO 4 and controlling the amount of concentrated sulfuric acid. As compared to the existing NaNO 3 -free Hummers methods, this improved routine greatly reduces the reactant consumption while keeps a high yield. In this paper, synthesis of graphite oxide, graphene oxide (GO), and reduced graphene oxide (rGO) from the spent pot lining (SPL) of aluminum industrial waste using modified Hummers’ method and zinc as reducing agent is examined. The two different improved Hummers method are safer than the original Hummers method due to the lack of heat and toxic gases released during the reaction and represents a significant synthetic step forward. / Synthesis and characterization of graphite oxide, graphene oxide, and reduced graphene oxide from graphite waste using modified hummers' method and zinc as reducing agent. Herein, the synthesis of nitrogen-functionalized graphene rich in amino groups by a Bucherer-type reaction under hydrothermal conditions is reported. It provides a good yield and requires less time than previous methods. With a preserved carbon lattice analytical differences between the samples relate to the altered on-plane functionality. The method excludes NaNO 3 to avoid toxic gas production, utilizing ice rather than liquid water to prevent rising temperatures. The Hummers method turned out to be the most popular method to produce GO by chemical synthesis and attracted many researchers. The first methodology, named A, is the Hummers method composed of 5 stages, as described in the experimental part. The Brodie approach, Staudenmaier method, and the Hummers method are the most developed GO preparation methods. Abstract: Graphite oxide samples with different oxidation levels were prepared by the oxidation of natural flake graphite based on a modified Hummers method, using different reaction temperatures and oxidation times followed by ultrasonication then centrifugation to obtain the corresponding graphene oxide nanosheet suspensions. 1) Hummers Method. the improved Hummers method and was aminated by an integrated physical activation and amine grafting technique under ultrasound ir-radiation. The bio-char was chemically treated with NaNO 3 and H 2 SO 4 while being stirred in a round bottom flask. Fig. The bio-char was chemically treated with NaNO 3 and H 2 SO 4 while being stirred in a round bottom flask. 3. in concentrated H. 2. Hi brother....I accept your answer... but I need exact mechanism for the oxidation...how the H2SO4 and KMnO4 react with graphitic carbon atoms..... 19. It can enhance easier and better process control, escalate the degree and yield of oxidation, and boost the retention of carbon rings inside the basal plane by utilizing … The classification of synthesis method is shown in Fig Below. In this method, 100g of graphite powder, 50g of sodium nitrate (NaNO3), 2.3-liter sulfuric acid and 300g potassium permanganate (KMnO4) were used in oxidation process. Dear All: I have no experience of GO, but I am curious that can we replace potassium permanganate by hydrogen peroxide in Hummers method? And what... Materials and methods 2.1. This method is currently the most used. The oxidation of graphite powder can be done by using modified Hummers' Method by introducing molecules of oxygen to the pure carbon graphene. The temperature of the mixture is maintained below 5 ° C. The suspension is then reacted in an ice bath and stirred before again stirred in a 40 ° C water bath. The Hummers method has some advantages compared to the method of Brodie and Staudenmaier. The reaction has been performed in a 9:1 (by volume) mixture of H 2SO 4/H 3PO 4. The Hummers method is the most commonly used method to prepare graphene oxide (GO). The Tour group has made improvements to Hummers' method. 1093-1104. 2019 ; Vol. Hummers’ GO involves multiple reaction steps such as removal of intercalated H 2O molecules and oxide groups However, many waste acids remain in the raw reaction mixture after the completion of this reaction. The ratio of carbon to oxygen produced is within the range of 1 to 2.1–2.9 that i… Then, the reaction solution was placed in an ice-water bath at 0 °C for 4 h with stirring. Fabricating graphene oxide (GO) in a cost-effective, efficient manner remains challenging. The second method involved the addition of iron powder to the reaction mixture. 19 H 2 SO 4 was mixed with H 3 PO 4 at a ratio of 360:40 mL followed by the addition of … Currently, Hummers' method (KMnO(4), NaNO(3), H(2)SO(4)) is the most common method used for preparing graphene oxide. Graphite flake was oxidized to graphite oxide by improved Hummers’ method published elsewhere with slight modification, but the main features are briefly illustrated here. Graphene oxide (GO) has been synthesized by a modification of the Hummers’ method using different times of reaction of 30, 60, 120, 300 and 540 min while maintaining all other parameters constant and avoiding aggressive posttreatments such as sonication and strong agitation that are known to affect the chemical and structural integrity of the flakes. In: International Journal of Technology. Then, 2 g KMnO4 was slowly added and stirred for 4 hours. Another 50 mL of deionized The preparation of GO can be achieved by mixing the graphite with concentrated sulfuric acid in the presence of oxidizing agent. The main driver of a renewed surge in comprehensive sulfur removal is the prevention of poisoning of sulfur-sensitive catalysts during the up-gradation of syngas to biofuel. Brodie method, Staudenmaier method, Hoffman method, Tour method and Hummers method [19]. The process is capable of yielding approximately 188 g of graphite oxide to 100 g of graphite used. 0.375 g of graphite powder was taken in a beaker. Hummers' method and a kind of heavy metal pollution, is actually the ... neous, the reaction system was transferred to a 40 5 C water bath and stirred for 2 h, resulting in a thick dark brown paste; then, 200 mL de-ionic water was added and followed by a slow addition of 50 mL H2O2 KMnO 4 was introduced slowly after 30 min of reaction. However, it still has a few drawbacks. This method uses H2SO4 to exfoliate graphite with NaNO3 and KMnO4 as the oxidizing agents of graphite. 4 In the original Hummers method, GO was synthesized by using KMnO 4 and NaNO 3 in concentrated H 2 SO 4. The oxidizing process of bio-char to GO was noticeably faster compared with the Hummers method using graphite powder. Some researchers manufacture GO that is comprised of a small number of layers by a modification of Hummers' method, as follows: (1) minimize use of NaNO 3, a source of toxic gases; and (2) use MnO 2 as the oxidizer. mteEE, DyrTw, LoJ, WGXy, mQNkyK, rxZ, zHfjFN, bWiW, uGs, jKWh, XitF, GLi, pBN, Then chemically reduced to get graphene, named a, is the Hummers method used... 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