Catalytic carbonization of polypropylene into cup-stacked carbon nanotubes with high performances in adsorption of heavy metallic ions and organic dyes

In this study, amino-functionalized multi-walled carbon nanotubes ( MWCNTs - NH 2) were successfully synthesized via an improved method and used for removal of organic dyes in aqueous solution. The synthesized MWCNTs - NH 2 were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscope (SEM), etc. The adsorption capacity and selectivity of MWCNTs - NH 2 for organic dyes was evaluated using rhodamine B ( RhB ), malachite green (MG), methyl orange (MO) and congo red (CR) as models. The selective adsorption toward anionic dyes was found for the MWCNTs - NH 2, and MO was selected as a typical anionic dye to deeply investigate the adsorption kinetics, equilibrium isotherms and thermodynamic parameters of the adsorption process. The adsorption kinetics and equilibrium isotherms data fitted well with the pseudo-second-order kinetic equation and Langmuir isotherm model. The thermodynamics study revealed that the adsorption of MO onto MWCNTs - NH 2 was spontaneous, exothermic and physisorptive in nature. The results indicated that MWCNTs - NH 2 are promising nanomaterials for removal of anionic dyes from industrial wastewater.

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Plasmonic enhancement of SERS measured on molecules in carbon nanotubes

Faraday Discussions ◽

10.1039/c7fd00127d ◽

2017 ◽

Vol 205 ◽

pp. 85-103 ◽

Cited By ~ 10

Author(s):

Niclas S. Mueller ◽

Sebastian Heeg ◽

Patryk Kusch ◽

Etienne Gaufrès ◽

Nathalie Y.-W. Tang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Surface Roughness ◽

Organic Dyes ◽

Plasmonic Enhancement ◽

Electromagnetic Enhancement ◽

Atomic Force ◽

Dynamic Charge ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering ◽

Walled Carbon Nanotubes

We isolated the plasmonic contribution to surface-enhanced Raman scattering (SERS) and found it to be much stronger than expected. Organic dyes encapsulated in single-walled carbon nanotubes are ideal probes for quantifying plasmonic enhancement in a Raman experiment. The molecules are chemically protected through the nanotube wall and spatially isolated from the metal, which prevents enhancement by chemical means and through surface roughness. The tubes carry molecules into SERS hotspots, thereby defining molecular position and making it accessible for structural characterization with atomic-force and electron microscopy. We measured a SERS enhancement factor of 106 on α-sexithiophene (6T) molecules in the gap of a plasmonic nanodimer. This is two orders of magnitude stronger than predicted by the electromagnetic enhancement theory (104). We discuss various phenomena that may explain the discrepancy (including hybridization, static and dynamic charge transfer, surface roughness, uncertainties in molecular position and orientation), but found all of them lacking in enhancement for our probe system. We suggest that plasmonic enhancement in SERS is, in fact, much stronger than currently anticipated. We discuss novel approaches for treating SERS quantum mechanically that appear promising for predicting correct enhancement factors. Our findings have important consequences on the understanding of SERS as well as for designing and optimizing plasmonic substrates.

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Nanoarchitectonic Composites of Mixed and Covalently Linked Multiwalled Carbon Nanotubes and Tetra-[α-(p-amino)benzyloxyl] Phthalocyanine Zinc(II)

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17472 ◽

2020 ◽

Vol 20 (5) ◽

pp. 2713-2721 ◽

Cited By ~ 1

Author(s):

Guifen Lu ◽

Xudong Liu ◽

Peng Zhang ◽

Li Bao ◽

Bosheng Zhao

Keyword(s):

Carbon Nanotubes ◽

Multiwalled Carbon Nanotubes ◽

Photocatalytic Performance ◽

Organic Dyes ◽

Spectroscopic Methods ◽

Multiwalled Carbon ◽

Photodegradation Efficiency ◽

Aqueous Environments ◽

Covalently Linked ◽

Excellent Stability

The nanoarchitectonic composites mixed-ZnPc-fMWCNT and linked-ZnPc-fMWCNT were prepared through tetra-[α-(p-amino)benzyloxyl]phthalocyanine Zinc(II) (ZnPc) mixed and covalently linked to multiwalled carbon nanotubes (MWCNTs), respectively. Various spectroscopic methods were used to identify the nanocomposites formed between ZnPc and MWCNTs whether by π–π interaction or by covalent linking. Their photocatalytic properties were fully investigated by carrying out the photodegradation of Rhodamine B (RhB) in aqueous solution under visible light irradiation. The nanocomposites displayed excellent photocatalytic performance, with the photodegradation efficiency as high as 94% for linked-ZnPc-fMWCNT and 83% for mixed-ZnPc-fMWCNT within 3 h irradiation. The repetition test revealed that both nanocomposites have excellent stability and recyclability, and then they are promising candidates as eco-friendly photocatalysts for degradation of organic dyes in aqueous environments.

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