scholarly journals Structural transformation of multiwalled carbon nanotubes under γ-ray irradiation

2010 ◽  
Vol 59 (1) ◽  
pp. 447
Author(s):  
Yang Tong-Zai ◽  
Luo Shun-Zhong
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Structural Transformation ◽  
Multiwalled Carbon ◽  
Γ Ray

Deformation of catalytically grown carbon nanotubes induced by annealing under high pressure

2000 ◽  
Vol 15 (1) ◽  
pp. 253-261 ◽  
Author(s):  
Ming Zhang ◽  
C. L. Xu ◽  
L. M. Cao ◽  
D. H. Wu ◽  
W. K. Wang
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
High Pressure ◽  
Multiwalled Carbon Nanotubes ◽  
Structural Transformation ◽  
Annealing Temperature ◽  
Structural Transformations ◽  
Microstructural Change ◽  
Multiwalled Carbon

A study of the structural transformation of catalytically grown carbon nanotubes induced by annealing under high pressure is presented in this paper, in which the atomic details of the microstructural transformations have been monitored mainly with electron microscopy. The microstructural change from the multiwalled carbon nanotubes into a quasi-spherical onion becomes obvious just at 770 °C under 5.5 GPa. The nanotubes deform and almost transform into nanographite ribbons directly when the annealing temperature is above 950 °C under 5.5 GPa. It is suggested that the pressure and temperature play an important role in the structural transformations of multiwalled carbon nanotubes described here.

Effect of Multiwalled Carbon Nanotubes On Mechanical Properties of Concrete

2012 ◽  
Vol 2 (6) ◽  
pp. 166-168 ◽  
Author(s):  
Dr.T.Ch.Madhavi Dr.T.Ch.Madhavi ◽  
◽  
Pavithra.P Pavithra.P ◽  
Sushmita Baban Singh Sushmita Baban Singh ◽  
S.B.Vamsi Raj S.B.Vamsi Raj ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon

Sorption of Bisphenol A in Aqueous Solutions on Irradiated and as-Grown Multiwalled Carbon Nanotubes

2018 ◽  
Vol 69 (5) ◽  
pp. 1233-1239
Author(s):  
Raluca Madalina Senin ◽  
Ion Ion ◽  
Ovidiu Oprea ◽  
Rusandica Stoica ◽  
Rodica Ganea ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Bisphenol A ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Adsorption Process ◽  
Sorption Process ◽  
Multiwalled Carbon ◽  
Before And After ◽  
Kinetic Sorption

In this study, non-irradiated and weathered multiwalled carbon nanotubes (MWCNTs) obtained through irradiation, were studied as adsorbents for BPA, both nanomaterials being characterized before and after the adsorption process. The objectives of our investigation were to compare the characteristics of non-irradiated and irradiated MWCNTs, to evaluate the adsorption capacity of BPA by pristine and irradiated MWCNTs and to determine the variation of the kinetic, sorption and thermodynamic parameters during sorption process using both sorbents.

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

2020 ◽  
Vol 16 (7) ◽  
pp. 905-913
Author(s):  
Youyuan Peng ◽  
Qingshan Miao
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Ph Value ◽  
Biological Fluids ◽  
Water Soluble ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Green Dispersive Micro Solid-Phase Extraction using Multiwalled Carbon Nanotubes for Preconcentration and Determination of Cadmium and Lead in Food, Water, and Tobacco Samples

2020 ◽  
Vol 16 (4) ◽  
pp. 381-392
Author(s):  
Ayman A. Gouda ◽  
Ali H. Amin ◽  
Ibrahim S. Ali ◽  
Zakia Al Malah
Keyword(s):  
Carbon Nanotubes ◽  
Solid Phase Extraction ◽  
Multiwalled Carbon Nanotubes ◽  
Solid Phase ◽  
Certified Reference Materials ◽  
Phase Extraction ◽  
Multiwalled Carbon ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Separation And Preconcentration

Background: Cadmium (Cd2+) and lead (Pb2+) have acute and chronic effects on humans and other living organisms. In the present work, new, green and accurate dispersive micro solid-phase extraction (DμSPE) method for the separation and preconcentration of trace amounts of cadmium (Cd2+) and lead (Pb2+) ions in various food, water and tobacco samples collected from Saudi Arabia prior to its Flame Atomic Absorption Spectrometric (FAAS) determinations was developed. Methods: The proposed method was based on a combination of oxidized multiwalled carbon nanotubes (O-MWCNTs) with a new chelating agent 5-benzyl-4-[4-methoxybenzylideneamino)-4H- 1,2,4-triazole-3-thiol (BMBATT) to enrich and separate trace levels of Cd2+ and Pb2+. The effect of separation parameters was investigated. The validation of the proposed preconcentration procedure was performed using certified reference materials. Results: Analyte recovery values ranged from 95-102%, indicating that the method is highly accurate. Furthermore, precision was demonstrated by the relative standard deviation (RSD < 3.0%). The limits of detection were 0.08 and 0.1 μg L−1 for Cd2+ and Pb2+ ions, respectively. The preconcentration factor was 200. Conclusion: The proposed method was used for the estimation of Cd2+ and Pb2+ ion content in various real samples, and satisfactory results were obtained. The proposed method has high adsorption capacity, rapid adsorption equilibrium, extremely low LODs, high preconcentration factors and shortens the time of sample preparation in comparison to classical SPE.

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