scholarly journals Sulfonitric Treatment of Multiwalled Carbon Nanotubes and Their Dispersibility in Water

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2442 ◽  
Author(s):  
Hui Liu ◽  
Jianfeng Wang ◽  
Jiachen Wang ◽  
Suping Cui
Keyword(s):  
Carbon Nanotubes ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Oxidation Degree ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Scattering Measurements ◽  
Ft Ir

In this study, Multiwalled carbon nanotubes (MWCNTs) were oxidized by a mixture of sulfuric acid and nitric acid (V:V = 3:1) at 70 °C for 1, 2, and 4 h, respectively. The oxidized MWCNTs were characterized by N2 adsorption, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), and Raman spectroscopy to determine the oxidation degree. The dispersion of the MWCNTs was investigated by UV-vis-NIR, SEM, and dynamic light scattering measurements. Results show that sulfonitric treatment increased the surface area and total pore volume and reduced the average pore diameter of MWCNTs. The treatment promoted the formation of oxidized species on the surface MWCNTs, as identified by FT-IR, TGA, and X-ray photoelectron spectroscopy measurements, and more oxygen-containing functional groups were generated when treatment time was extended. Moreover, a general relationship between oxidation degree and dispersibility of MWCNTs in water was established. UV-vis-NIR and dynamic light scattering measurements and SEM images revealed that MWCNTs with higher oxidation degree showed better dispersibility in water.

Synthesis and Performance of Dopa-Modified Multiwalled Carbon Nanotubes

2012 ◽  
Vol 184-185 ◽  
pp. 1289-1293
Author(s):  
Lu Zhi Wang ◽  
Lin Yu ◽  
Xiao Ling Cheng ◽  
Jun He ◽  
Le Jia Lin ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Multiwalled Nanotubes ◽  
Mixed Acid ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Performance

The Dopamine-modified multiwalled carbon nanotubes (MWNT-Dopa) were synthesized by chemical reaction between dopamine (Dopa) and multiwalled carbon nanotubes which oxidazed by mixed-acid (MWNT-COOH). The structure of MWNT-Dopa were analyzed by Fourier transform infrared spectroscopy (FT-IR), Thermogravimetric (TG), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques and the dispersity of MWNT-Dopa were studied by Dispersion stability analyzer. The results show that dopamine has been grafted on multiwalled carbon nanotubes successfully, and a dopamine layer which wraps on the surface of multiwalled nanotubes make multiwalled nanotubes have outstanding dispersity in water.

Multiwalled Carbon Nanotubes Covered with Cobalt (II) Phthalocyanine by In Situ Synthesis and its Electrochemical Sensing Performance towards DA and UA

2014 ◽  
Vol 809-810 ◽  
pp. 43-52
Author(s):  
Hua Hua Wang ◽  
Nan Li ◽  
Kai Li ◽  
Yuan Bu ◽  
Wen Le Dai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Simultaneous Detection ◽  
Thick Layer ◽  
Electrochemical Sensing ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Platinum Particles

Multiwalled carbon nanotubes (MWCNTs) as an excellent supporter covered with a thick layer of cobalt phthalocyanine (CoPc) were prepared by in-situ synthesis. Platinum particles were adopted to enhance the conductivity of CoPc-MWCNTs. The final nanocomposite Pt-CoPc-MWCNTs was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Strong aromatic π-π stacking between MWCNTs and CoPc made CoPc in-situ forming on MWCNTs. With homogeneous thickness of CoPc covered on the MWCNTs and Pt particles equally distributed, the nanocomposite was used as electrocatalyst. The electrochemical properties of the composite got researched by casting the dispersion of Pt-CoPc-MWCNTs on the glassy carbon electrode. Compared with other modified electrodes, Pt-CoPc-MWCNTs/GC electrode exhibited excellent electrochemical activity towards dopamine (DA) and uric acid (UA). Linear responses for DA and UA were obtained in the ranges of 5 to 170 μM and 5 to 100 μM, and limits of detection were 2.6 and 1.4 μM (S/N= 3), respectively. Simultaneous detection of DA and UA in the presence of ascorbic acid (AA) also displayed selective property, with no interference to each other.

Removal of Pb(II) and Cu(II) from aqueous solution using multiwalled carbon nanotubes/iron oxide magnetic composites

2011 ◽  
Vol 63 (5) ◽  
pp. 917-923 ◽  
Author(s):  
Jun Hu ◽  
Donglin Zhao ◽  
Xiangke Wang
Keyword(s):  
Carbon Nanotubes ◽  
Iron Oxide ◽  
Multiwalled Carbon Nanotubes ◽  
Sorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Precipitation Method ◽  
Multiwalled Carbon ◽  
Magnetic Composites ◽  
X Ray

Multiwalled carbon nanotubes (MWCNTs)/iron oxide magnetic composites (named as MCs) were prepared by co-precipitation method, and were characterised by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in detail. The prepared MCs were employed as an adsorbent for the removal of Pb(II) and Cu(II) ions from wastewater in heavy metal ion pollution cleanup. The results demonstrated that the sorption of Pb(II) and Cu(II) ions was strongly dependent on pH and temperature. The experimental data were well described by Langmuir model, and the monolayer sorption capacity of MCs was found to vary from 10.02 to 31.25 mg/g for Pb(II) and from 3.11 to 8.92 mg/g for Cu(II) at temperature increasing from 293.15 to 353.15 K at pH 5.50. The sorption capacity of Pb(II) on MCs was higher than that of Cu(II), which was attributed to their ionic radius, hydration energies and hydrolysis of their hydroxides. The thermodynamic parameters (i.e., ΔH0, ΔS0 and ΔG0) were calculated from temperature dependent sorption isotherms, and the results indicated that the sorption of Pb(II) and Cu(II) ions on MCs were spontaneous and endothermic processes.

Well-Crystallized SnO2 Nanocrystals Homogeneously and Intimately Coated on Multiwalled Carbon Nanotubes by a Simple Surfactant-Free Hydrothermal Method

2011 ◽  
Vol 686 ◽  
pp. 474-481 ◽  
Author(s):  
Y.Q. Guo ◽  
Rui Qin Tan ◽  
Z.Y. Cao ◽  
Wei Jie Song
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Hydrothermal Reaction ◽  
Ph Value ◽  
Ethanol Solution ◽  
Multiwalled Carbon ◽  
X Ray ◽  
In Situ Deposition

A simple approach to the in situ deposition of well-crystallized SnO2nanocrystals on the surface of multiwalled carbon nanotubes (MWCNTs) in the ethanol solution system of SnCl2 was presented in this paper. The well-crystallized SnO2nanocrystals with small and uniform crystal size (4~5 nm) can be tightly and homogenously coated on the outside surface of the MWCNTs entirely. The prepared nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen BET measurements. It is found that the hydrothermal reaction plays an important role for the crystal growth of the SnO2nanocrystals on the surface of MWCNTs, and the crystallinity of the SnO2nanocrystals can be controlled by varying the pH value or the hydrothermal reaction time. It is found that a unique structure of leaf-like SnO2nanosheets hanging on the MWCNTs was obtained when using water as the solvent of SnCl2instead of ethanol. The gas sensing performance of the SnO2/MWCNTs nanocomposites was also investigated.

Adsorptive extraction of uranium (VI) from seawater using dihydroimidazole functionalized multiwalled carbon nanotubes

2018 ◽  
Vol 106 (9) ◽  
pp. 719-731 ◽  
Author(s):  
Kun Tian ◽  
Jinling Wu ◽  
Jianlong Wang
Keyword(s):  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Alkali Resistance ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Infrared Scanning ◽  
Seawater Ph ◽  
Functionalized Multiwalled Carbon Nanotubes

Abstract The adsorptive extraction of uranium (VI) was investigated using multiwalled carbon nanotubes functionalized with dihydroimidazole (DIM-MWCNTs). Dihydroimidazole was grafted onto the surface of MWCNTs via silane coupling agent, N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole. The new adsorbent was characterized using Fourier transform infrared, scanning electron microscope and X-ray Photoelectron Spectroscopy. DIM-MWCNTs were compared with MWCNTs and amidoxime modified MWCNTs (AO-MWCNTs) for uranium adsorption under seawater conditions. The adsorption capacity of uranium onto DIM-MWCNTs was 54.9 mg g−1 at 298 K, which was about 4 times of MWCNTs and similar to that of AO-MWCNTs. Compared with AO-MWCNTs, DIM-MWCNTs were more suitable for seawater pH, and less affected by vanadium. Although DIM-MWCNTs were more affected by carbonate than AO-MWCNTs, DIM-MWCNTs maintained a higher adsorption capacity than AO-MWCNTs due to its alkali resistance. Pyridine-like nitrogen (CH=N–CH) contributed to the adsorption of uranium. The results suggested that DIM-MWCNTs were a potential effective adsorbent for the separation of uranium under seawater condition.

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