scholarly journals Fast Identification and Quantification of Graphene Oxide in Aqueous Environment by Raman Spectroscopy

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 770 ◽  
Author(s):  
Shengnan Yang ◽  
Qian Chen ◽  
Mengyao Shi ◽  
Qiangqiang Zhang ◽  
Suke Lan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Environmental Risk ◽  
Large Scale ◽  
Carbon Nanomaterials ◽  
Aqueous Environment ◽  
Fast Identification ◽  
Aqueous Environments ◽  
Potential Applications ◽  
Identification And Quantification

Today, graphene nanomaterials are produced on a large-scale and applied in various areas. The toxicity and hazards of graphene materials have aroused great concerns, in which the detection and quantification of graphene are essential for environmental risk evaluations. In this study, we developed a fast identification and quantification method for graphene oxide (GO) in aqueous environments using Raman spectroscopy. GO was chemically reduced by hydrazine hydrate to form partially reduced GO (PRGO), where the fluorescence from GO was largely reduced, and the Raman signals (G band and D band) were dominating. According to the Raman characteristics, GO was easily be distinguished from other carbon nanomaterials in aqueous environments, such as carbon nanotubes, fullerene and carbon nanoparticles. The GO concentration was quantified in the range of 0.001–0.6 mg/mL with good linearity. Using our technique, we did not find any GO in local water samples. The transport of GO dispersion in quartz sands was successfully quantified. Our results indicated that GO was conveniently quantified by Raman spectroscopy after partial reduction. The potential applications of our technique in the environmental risk evaluations of graphene materials are discussed further.

scholarly journals The Role of Bio-Extracted Reduced Graphene Oxide in the Crystallization Kinetics of Chitosan Bio-Polymer

2021 ◽  
pp. 1-4
Author(s):  
Solomon L Joseph ◽  
◽  
Agumba O John ◽  
Fanuel M Keheze ◽  
◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Carbon Nanomaterials ◽  
High Strength ◽  
Limiting Factor ◽  
Reduced Graphene ◽  
Electrical Conductivities ◽  
Coating Method ◽  
Potential Applications ◽  
New Applications

Carbon nanomaterials have recently attracted wide scientific applications due to their tunable properties. These novel materials act as best fillers that can provide substantial benefits due to their high strength, thermal conductivity, and electrical conductivities. With their huge applications as bulk materials, when implemented in polymer matrix as fillers, they give rise to new promising materials with which their properties can be tuned to suit a particular application. Besides the development of these new nanocomposite materials, there exist some challenges which must be fully surpassed to explore the potentiality of application of carbon-based nanocomposites. Reduced graphene oxide is one of the carbon derivatives which has attracted the current advancement in technology, and recently, it found its new applications in super capacitors used in electronic industries. The limiting factor for its exploration is the affordability. New and affordable sources of these graphene-based nanomaterial have to be devised, for fully realization of their potential applications. In this study, reduced graphene oxide and the bio-polymer chitosan were extracted from the locally available bio waste materials. Nanocomposites were prepared at 50% rGO: chitosan ratio. The films were then prepared by spin coating method. Prepared films were subjected to morphological analysis. From the results, it was observed that rGO induced chitosan crystallization, which led to formation of dendritic structures. Cellulose nanocrystals have thus displayed temperature dependent positive uniaxial birefringence

Synthesis of Graphene Oxide from Alternative Sources

2016 ◽  
Vol 38 ◽  
pp. 96-100
Author(s):  
Miguel Sanchez ◽  
Mauro Cesar Terence ◽  
Juan Alfredo Guevara Carrió
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Large Scale ◽  
Two Dimensional ◽  
Hummers Method ◽  
Exothermic Process ◽  
Alternative Sources ◽  
Redox Method ◽  
Modified Hummers Method

Two-dimensional films of graphene oxide (GO) have been synthesized using various oxidation methods such as the conventional or modified Hummers method. The redox method for graphite has shown promise at producing GO films on a large scale. However, this method is a very exothermic process that liberates gases that are harmful to the environment and humans. This article addresses the characterization of graphene oxide from alternative sources of carbon and using the dry method. Comparative studies performed using Raman spectroscopy suggest that this method is both promising and more environmentally friendly.

scholarly journals Lemon Juice Assisted Green Synthesis of Reduced Graphene Oxide and Its Application for Adsorption of Methylene Blue

Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 96
Author(s):  
Md. Mahiuddin ◽  
Bungo Ochiai
Keyword(s):  
Methylene Blue ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Large Scale ◽  
Carbon Nanomaterials ◽  
Cost Effective ◽  
Lemon Juice ◽  
Scale Production ◽  
Reduced Graphene ◽  
Microscopic Evaluation

Sustainable synthesis of reduced graphene oxide (rGO) is of crucial significance within the development of carbon nanomaterials. In this study, a green and eco-friendly strategy for the synthesis of rGO using lemon juice as the reducing agent for graphene oxide (GO) without using toxic and harmful chemicals was demonstrated. The reduction with lemon juice effectively eliminated the oxygen-containing functionalities of GO and regenerated the conjugated systems as confirmed by the UV-vis and FTIR spectroscopic and X-ray diffraction analyses. Microscopic evaluation showed the successful manufacturing of exfoliated and separated few layers of nano-sheets of rGO. The application of the resultant rGO as an adsorbent for organic pollutants was investigated using methylene blue (MB) as a model. The adsorption kinetics of MB on rGO is best matched with the pseudo-second-ordered kinetic model and the Langmuir model with a high adsorption capacity of 132.2 mg/g. The rGO exhibited good reusability with a removal efficiency of 80.4% in the fourth cycle. This green method provides a new prospect for the large-scale production of rGO in a cost-effective and safe manner.

scholarly journals Investigation of Carbon Nanotube Grafted Graphene Oxide Hybrid Aerogel for Polystyrene Composites with Reinforced Mechanical Performance

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 735
Author(s):  
Yanzeng Sun ◽  
Hui Xu ◽  
Zetian Zhao ◽  
Lina Zhang ◽  
Lichun Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Rational Design ◽  
Large Scale ◽  
Carbon Nanomaterials ◽  
Mechanical Performance ◽  
Polymer Matrix Composites ◽  
Three Dimensional ◽  
Scale Production

The rational design of carbon nanomaterials-reinforced polymer matrix composites based on the excellent properties of three-dimensional porous materials still remains a significant challenge. Herein, a novel approach is developed for preparing large-scale 3D carbon nanotubes (CNTs) and graphene oxide (GO) aerogel (GO-CNTA) by direct grafting of CNTs onto GO. Following this, styrene was backfilled into the prepared aerogel and polymerized in situ to form GO–CNTA/polystyrene (PS) nanocomposites. The results of X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy indicate the successful establishment of CNTs and GO-CNT and the excellent mechanical properties of the 3D frameworks using GO-CNT aerogel. The nanocomposite fabricated with around 1.0 wt% GO-CNT aerogel displayed excellent thermal conductivity of 0.127 W/m∙K and its mechanical properties were significantly enhanced compared with pristine PS, with its tensile, flexural, and compressive strengths increased by 9.01%, 46.8%, and 59.8%, respectively. This facile preparation method provides a new route for facilitating their large-scale production.

scholarly journals Toward Large-Scale Production of Oxidized Graphene

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 279 ◽  
Author(s):  
Talia Tene ◽  
Gabriela Tubon Usca ◽  
Marco Guevara ◽  
Raul Molina ◽  
Francesco Veltri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Large Scale ◽  
Scale Production ◽  
Gravimetric Analysis ◽  
Morphological Studies ◽  
Toxic Gases ◽  
Large Scale Production ◽  
Potential Applications ◽  
Time Required

The oxidative exfoliation of graphite is a promising approach to the large-scale production of graphene. Conventional oxidation of graphite essentially facilitates the exfoliation process; however, the oxidation procedure releases toxic gases and requires extensive, time-consuming steps of washing and reduction to convert exfoliated graphene oxide (GO) into reduced graphene oxide (rGO). Although toxic gases can be controlled by modifying chemical reactions, filtration, dialysis, and extensive sonication are unfavorable for large-scale production. Here, we report a complete, scalable, and green synthesis of GO, without NaNO3, followed by reduction with citric acid (CA). This approach eliminates the generation of toxic gases, simplifies the washing steps, and reduces the time required to prepare rGO. To validate the proposed method, we present spectroscopical and morphological studies, using energy-dispersive X-ray spectroscopy (EDS), UV-visible spectroscopy, infrared spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thermal gravimetric analysis (TGA) is used to analyze the thermal properties of GO and rGO. This eco-friendly method proposes a complete guideline protocol toward large-scale production of oxidized graphene, with potential applications in supercapacitors, fuel cells, composites, batteries, and biosensors.

scholarly journals Applicability of Atmospheric Pressure Plasma Jet (APPJ) Discharge for the Reduction in Graphene Oxide Films and Synthesis of Carbon Nanomaterials

2021 ◽  
Vol 7 (4) ◽  
pp. 71
Author(s):  
Sri Hari Bharath Vinoth Kumar ◽  
Josefa Ibaceta-Jaña ◽  
Natalia Maticuic ◽  
Krystian Kowiorski ◽  
Matthias Zelt ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Atmospheric Pressure ◽  
Carbon Nanomaterials ◽  
Atmospheric Pressure Plasma ◽  
Reduction Process ◽  
Surface Cleaning ◽  
Plasma Jets ◽  
X Ray ◽  
Pressure Plasma

Atmospheric pressure plasma jets (APPJ) are widely used in industry for surface cleaning and chemical modification. In the recent past, they have gained more scientific attention especially in the processing of carbon nanomaterials. In this work, a novel power generation technique was applied to realize the stable discharge in N2 (10 vol.% H2) forming gas in ambient conditions. This APPJ was used to reduce solution-processed graphene oxide (GO) thin films and the result was compared with an established and optimized reduction process in a low–pressure capacitively coupled (CCP) radiofrequency (RF) hydrogen (H2) plasma. The reduced GO (rGO) films were investigated by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Effective deoxygenation of GO was observed after a quick 2 s treatment by AAPJ. Further deoxygenation at longer exposure times was found to proceed with the expense of GO–structure integrity. By adding acetylene gas into the same APPJ, carbon nanomaterials on various substrates were synthesized. The carbon materials were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analyses. Fullerene-like particles and graphitic carbon with short carbon nanotubes were detected on Si and Ag surfaces, respectively. We demonstrate that the APPJ tool has obvious potential for the versatile processing of carbon nanomaterials.

Synthesis and Characterization of TiO2 Nanotube/Hydroquinone Hybrid Structure

2007 ◽  
Vol 7 (2) ◽  
pp. 458-462 ◽  
Author(s):  
Yuanyuan Jia ◽  
Alfred Kleinhammes ◽  
Harsha Kulkarni ◽  
Kristopher McGuire ◽  
L. E. McNeil ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Absorption ◽  
Local Structure ◽  
Structural Changes ◽  
Hybrid Structure ◽  
Synthesis And Characterization ◽  
Aqueous Environment ◽  
Optical Absorption Peak ◽  
Potential Applications

It is shown that 1,4-benzenediol (hydroquinone) and TiO2 nanotubes can form a hybrid structure that is stable in aqueous environment. The incorporation of hydroquinone restores the local structure of nanotubes to anatase-like as evidenced by Raman spectroscopy. Subtle overall structural changes take place upon annealing of the hybrid structure contributing to its stability. The hybrid system shows a broad optical absorption peak extending significantly beyond 700 nm with potential applications in photocatalysis and photoelectrochemistry.

scholarly journals Extraordinary thermal behavior of graphene oxide in air for electrode applications

2021 ◽  
Author(s):  
Joong Tark Han ◽  
Joon Young Cho ◽  
Jeong Hoon Kim
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Physical Properties ◽  
Thermal Behavior ◽  
Stability Of Solution ◽  
Exfoliated Graphene ◽  
Potential Applications ◽  
Thermal Stability Of

The thermal stability of solution-exfoliated graphene oxide (GO) in air is one of the most important physical properties influencing its potential applications. To date, majority of the GO prepared by...

scholarly journals C4 Bacterial Volatiles Improve Plant Health

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 682
Author(s):  
Bruno Henrique Silva Dias ◽  
Sung-Hee Jung ◽  
Juliana Velasco de Castro Oliveira ◽  
Choong-Min Ryu
Keyword(s):  
Plant Growth ◽  
Volatile Compounds ◽  
Large Scale ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Health ◽  
Systemic Resistance ◽  
Potential Applications ◽  
Plant Growth Promoting ◽  
Bacterial Volatiles

Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.

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