scholarly journals The Characteristics of Graphene Obtained from Rice Husk and Graphite

2019 ◽  
Vol 21 (2) ◽  
pp. 149 ◽  
Author(s):  
M.A. Seitzhanova ◽  
Z.A. Mansurov ◽  
M. Yeleuov ◽  
V. Roviello ◽  
R. Di Capua
Keyword(s):  
Graphene Oxide ◽  
Rice Husk ◽  
Elemental Analysis ◽  
Aromatic Carbon ◽  
Graphene Layers ◽  
Graphite Oxidation ◽  
Inorganic Matter ◽  
Overlapped Peaks ◽  
Final Residue ◽  
Weight Decrease

In this paper methods for obtaining graphene oxide from rice husk were developed, which using a downward approach based on a four-stage strategy: preliminary carbonization, desilication, activation with KOH, and exfoliation and its comparison with the method of graphite oxidation. The samples were analyzed by elemental analysis, SEM, Raman, TGA and FTIR. The elemental analysis show that the proposed approach allows to produce graphene materials with a carbon content around 70% and rich in inorganic matter (0–20 wt.%) (K, Fe, Si). To remove inorganic contents, purification and functionalization step were applied. The Raman spectra of the samples indicate the presence of a mixture of graphene layers and amorphous carbon. The thermogravimetric profile of samples is characterized by a slowly weight decrease up to a final residue of ~10 wt.%. FTIR spectra are characterized by the typical broad shape of large condensed aromatic carbon bonds; only the peak due to C=C stretching modes and the overlapped peaks between 900 and 1500 cm-1 due to skeleton vibrations are detected.

scholarly journals A Comparative Study of the ZnO Growth on Graphene and Graphene Oxide: The Role of the Initial Oxidation State of Carbon

2020 ◽  
Vol 6 (2) ◽  
pp. 41
Author(s):  
Miguel Angel Gomez-Alvarez ◽  
Carlos Morales ◽  
Javier Méndez ◽  
Adolfo del Campo ◽  
Fernando J. Urbanos ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Oxidation State ◽  
Atomic Ratio ◽  
Quasi Equilibrium ◽  
Initial Oxidation ◽  
Sio2 Substrate ◽  
Graphene Layers ◽  
Stages Of Growth ◽  
Early Stages

The role of the oxidation state of carbon on the early stages of growth of metal oxides was studied for the particular case of ZnO deposition on graphene and graphene oxide on SiO2 (G/SiO2 and GO/SiO2, respectively) substrates. The growth was carried out by thermal evaporation of metallic Zn under an oxygen atmosphere at room temperature. This technique permits quasi-equilibrium conditions during the oxide growth, allowing the characterization of the fundamental interaction between ZnO and the graphene-based substrates. Although in both cases ZnO follows a Volmer–Weber growth mode controlled by nucleation at defects, the details are different. In the case of the GO/SiO2 substrate, the nucleation process acts as a bottleneck, limiting the coverage of the complete surface and allowing the growth of very large ZnO structures in comparison to G/SiO2. Moreover, by studying the Zn-LMM Auger spectra, it is shown how the initial nature of the substrate influences the composition of the ZnO deposit during the very early stages of growth in terms of Zn/O atomic ratio. These results are compared to those previously reported regarding ZnO growth on graphite and graphene on Cu (G/Cu). This comparison allows us to understand the role of different characteristics of graphene-based substrates in terms of number of defects, oxidation state, graphene support substrate and number of graphene layers.

Preparation of Graphene Oxide Modified Rice Husk for Cr(VI) Removal

2019 ◽  
Vol 19 (11) ◽  
pp. 7035-7043 ◽  
Author(s):  
Tong Ouyang ◽  
Jidan Tang ◽  
Fang Liu ◽  
Chang-Tang Chang
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Alkaline Conditions ◽  
Rice Husk Biochar

The objective of this paper is to study the removal of Cr(VI) in aqueous solution by using a new graphene oxide-coated rice husk biochar composite (GO-RHB). GO-RHB is a synthetic material having a porous structure with lots of oxygen-containing functional groups and a large surface area that provide effective adsorption sites. Experiments showed that GO-RHB had higher adsorption capacity under acidic than under alkaline conditions. At pH of 2, GO-RHB has the maximum adsorption capacity(48.8 mg g−1). Equilibrium data obtained by fitting with the Langmuir and Freundlich models indicate that the reaction process was monolayer adsorption. The adsorption of Cr(VI) followed the pseudo-second-order kinetic model that illustrates chemical adsorption. Intraparticlediffusion studies further revealed that film diffusion was taking place. Moreover, the results of thermodynamics showed that the adsorption process was endothermic and spontaneous in nature. The removal mechanism of Cr(VI) was also explained in detail. The prepared adsorbent is highly efficient and might be useful than many other conventional adsorbent used for the removal of Cr(VI) from wastewater.

scholarly journals Review of Recent Developments in the Formulation of Graphene-Based Coatings for the Corrosion Protection of Metals and Alloys

2020 ◽  
Vol 1 (3) ◽  
pp. 296-327
Author(s):  
Bronach Healy ◽  
Tian Yu ◽  
Daniele da Silva Alves ◽  
Carmel B. Breslin
Keyword(s):  
Graphene Oxide ◽  
Corrosion Protection ◽  
Hexagonal Boron Nitride ◽  
Protective Coatings ◽  
Galvanic Corrosion ◽  
Metals And Alloys ◽  
Graphene Layers ◽  
Recent Developments ◽  
Double Hydroxides ◽  
Protection Of Metals

Corrosion is a naturally occurring phenomenon and there is continuous interest in the development of new and more protective coatings or films that can be employed to prevent or minimise corrosion. In this review the corrosion protection afforded by two-dimensional graphene is described and discussed. Following a short introduction to corrosion, the application of graphene in the formulation of coatings and films is introduced. Initially, reduced graphene oxide (rGO) and metallic like graphene layers are reviewed, highlighting the issues with galvanic corrosion. Then the more successful graphene oxide (GO), functionalised GO and polymer grafted GO-modified coatings are introduced, where the functionalisation and grafting are tailored to optimise dispersion of graphene fillers. This is followed by rGO coupled with zinc rich coatings or conducting polymers, GO combined with sol-gels, layered double hydroxides or metal organic frameworks as protective coatings, where again the dispersion of the graphene sheets becomes important in the design of protective coatings. The role of graphene in the photocathodic protection of metals and alloys is briefly introduced, while graphene-like emerging materials, such as hexagonal boron nitride, h-BN, and graphitic carbon nitride, g-C3N4, are then highlighted.

Graphene oxide conversion into controllably carboxylated graphene layers via photoreduction process in the inert atmosphere

2019 ◽  
Vol 28 (3) ◽  
pp. 221-225 ◽  
Author(s):  
Maxim K. Rabchinskii ◽  
Vladimir V. Shnitov ◽  
Dina Yu. Stolyarova ◽  
Sergei A. Ryzhkov ◽  
Marina V. Baidakova ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Inert Atmosphere ◽  
Graphene Layers ◽  
Oxide Conversion

scholarly journals Novel Green Synthesis of Graphene Layers using Zante Currants and Graphene Oxide

2018 ◽  
Vol 34 (6) ◽  
pp. 2832-2837 ◽  
Author(s):  
Mohd Zaid Ansari ◽  
Mohammad Nadeem Lone ◽  
Shabana Sajid ◽  
Weqar Ahmad Siddiqui
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Uv Spectrophotometry ◽  
Scale Production ◽  
Graphene Layers ◽  
Large Scale Production ◽  
Reduced Graphene ◽  
Reduction Effect ◽  
First Time ◽  
Facile Route

The present work shows a facile route for the preparation of graphene layers and for the first time Zante currants extract used for the effective deoxygenation of graphene oxide has been reported. Zante currants (ZC) extract reduce effectively GO into few layered structures of graphene (FLG). The morphology of few layers graphene and graphene oxide (GO) were investigated by SEM and TEM. Reduction effect on graphene oxide confirm by other technique like Raman, FTIR, XRD and UV spectrophotometry. This procedure keep away the use of hazardous chemicals, thus providing a new hope for large scale production of chemically reduced graphene.

3-Aminopropyl-triethoxysilane-functionalized rice husk and rice husk ash reinforced polyamide 6/graphene oxide sustainable nanocomposites

2017 ◽  
Vol 94 ◽  
pp. 417-430 ◽  
Author(s):  
Ahmad Allahbakhsh ◽  
Fereidoun Noei Khodabadi ◽  
Fatemeh Sadat Hosseini ◽  
Amir Hossein Haghighi
Keyword(s):  
Graphene Oxide ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Polyamide 6

scholarly journals Graphene oxide and H2 production from bioelectrochemical graphite oxidation

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Lu Lu ◽  
Cuiping Zeng ◽  
Luda Wang ◽  
Xiaobo Yin ◽  
Song Jin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
H2 Production ◽  
Graphite Oxidation

Graphene Oxide Colloidal Suspensions as Cutting Fluids for Micromachining: Part 1 — Fabrication and Performance Evaluation

2015 ◽  
Author(s):  
Bryan Chu ◽  
Eklavya Singh ◽  
Johnson Samuel ◽  
Nikhil Koratkar
Keyword(s):  
Graphene Oxide ◽  
Cutting Temperature ◽  
Colloidal Suspensions ◽  
Cutting Fluid ◽  
Droplet Spreading ◽  
Bulk Fluid ◽  
Graphene Layers ◽  
Lubrication Performance ◽  
Cooling And Lubrication ◽  
Lateral Length

This paper is aimed at investigating the effects of graphene oxide platelet (GOP) geometry (i.e., lateral size and thickness) and oxygen functionalization on the cooling and lubrication performance of GOP colloidal suspensions. The techniques of thermal reduction and ultrasonic exfoliation were used to manufacture three different types of GOPs. For each of these three types of GOPs, colloidal solutions with GOP concentrations varying between 0.1–1 wt% were evaluated for their dynamic viscosity, thermal conductivity and micromachining performance. The ultrasonically-exfoliated GOPs (with 2–3 graphene layers and lowest in-solution characteristic lateral length of 120 nm) appear to be the most favorable for micromachining applications. Even at the lowest concentration of 0.1 wt%, they are capable of providing a 51% reduction in the cutting temperature and a 25% reduction in the surface roughness value over that of the baseline semi-synthetic cutting fluid. For the thermally-reduced GOPs (with 4–8 graphene layers and in-solution characteristic lateral length of 562–2780 nm), a concentration of 0.2 wt% appears to be optimal. The findings suggest that the differences seen between the colloidal suspensions in terms of their droplet spreading, evaporation and the subsequent GOP film-formation characteristics may be better indicators of their machining performance, as opposed to their bulk fluid properties.

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