A simple and highly effective process for the purification of single-walled carbon nanotubes synthesized with arc-discharge

Cho, Hyeon Gu; Kim, Sang Won; Lim, Hyeong Jun; Yun, Chang; Lee, Heon Sang; Park, Chong Rae

doi:10.1016/j.carbon.2009.08.017

Cited by 28 publications

(12 citation statements)

References 18 publications

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“…19−21 However, even if high-quality CNTs can be prepared from the standard methods, they still fail in selectively removing carbonaceous impurities without excessive loss of CNTs, leading to low sample yield. 22 The main reason explaining this difficulty of eliminating carbon impurities without attacking the CNTs is their too close chemical reactivity. 23,24 Standard approaches use strong acids, which are known to damage the CNTs and lead to weak sample yield; they also create functional groups at the CNT surface and produce large amounts of amorphous carbon debris.…”

Section: Introductionmentioning

confidence: 99%

“…The purification of CNTs has been extensively desired, and various methods allow to efficiently remove metallic contamination. , Some methods to remove only catalyst residues consist of annealing the CNT powder at a temperature in the 2000–2500 °C range under N 2 , Ar, or vacuum. − However, even if high-quality CNTs can be prepared from the standard methods, they still fail in selectively removing carbonaceous impurities without excessive loss of CNTs, leading to low sample yield . The main reason explaining this difficulty of eliminating carbon impurities without attacking the CNTs is their too close chemical reactivity. , Standard approaches use strong acids, which are known to damage the CNTs and lead to weak sample yield; they also create functional groups at the CNT surface and produce large amounts of amorphous carbon debris .…”

Section: Introductionmentioning

confidence: 99%

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Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

et al. 2019

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Purity of carbon nanotubes (CNTs) is essential to avoid a dramatic decrease in their performances. In addition to metallic impurities, carbonaceous impurities have been shown to be responsible for pronounced effects. However, they are highly difficult to be selectively removed from CNT samples because of the similar chemical reactivity of these two kinds of carbon species. The existing purification methods often lead to high CNT consumption (>90 wt %). The proposed method consists of a one-pot gas-phase treatment combining chlorine and oxygen. The CNT powder maintained in a chlorine stream is submitted to oxygen at moderate temperature [350 and 500°C for single-walled CNTs (SWCNTs) and double-walled CNTs (DWCNTs), respectively], and the thermal treatment is then pursued at 900−1000°C under chlorine alone. Our work reveals that this approach is able to significantly improve the selectivity of elimination of carbonaceous impurities. Thanks to the proposed purification treatment, only 19 and 11 wt % of carbon species (mainly carbon impurities) are lost for DWCNTs and SWCNTs, respectively. The mechanism proposed involves a protective effect by grafting of chlorine favored to the CNT walls. Because our simple one-pot purification method is also versatile and scalable, it opens new perspectives for CNT applications in high-added value fields.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

et al. 2019

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“…By using a specific chelator for Fe(II) associated to a reducing agent iron was found in large part exposed to the solvent and therefore potentially active toward cells (Table 1). Several protocols were proposed to remove metal contaminants from MWCNT (Cho et al, 2009), that include chemical treatments with oxidizing acids (HNO 3 , H 2 SO 4 ) or thermal treatments at high temperature in inert atmosphere (Bougrine et al, 2001;Fenoglio et al, 2008). However these treatments also affect the total amount of defects of CNT.…”

Section: Preparation Of Iron-rich and Iron-free Mwcntmentioning

confidence: 99%

The Role of Iron Impurities in the Toxic Effects Exerted by Short Multiwalled Carbon Nanotubes (MWCNT) in Murine Alveolar Macrophages

Aldieri

Fenoglio

Cesano

et al. 2013

Journal of Toxicology and Environmental Health, Part A

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Lung toxicity mediated by multiwalled carbon nanotubes (MWCNT) has been widely demonstrated and recently associated with induction of carcinogenic asbestos-like effects, but the chemical features which drive this toxic effect have still not been well elucidated. The presence of metals as trace contaminants during MWCNT preparation, in particular iron (Fe) impurities, plays an important role in determining a different cellular response to MWCNT.Our goal was to clarify the mechanisms underlying MWCNT toxicity in correlation to the presence of Fe impurities by exposing murine alveolar macrophages to two different MWCNT samples, which differ only for the presence or absence of Fe. Data show that only Fe-rich MWCNT were significantly cytotoxic, genotoxic and induced a potent cellular oxidative stress, while Fe-free MWCNT did not exert any of these toxic effects. These results confirm that Fe content represents a very important key constituent in promoting MWCNT induced toxicity, and this needs to be taken into consideration when planning new, safer, preparation routes.Running Title: The role of impurities in MWCNT toxicity.

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“…The asproduced soot persistently contains a part of nonnanotube species: (i) carbonaceous impurities showing large range of size and cristallinity from completely amorphous carbon to more or less ordered or well-graphitized particles and (ii) particles of residual metal catalyst required for the synthesis of SWNT-type. Numerous treatments and procedures for mass purification have been proposed, they are based on physical processes and/or chemical treatments (Hou et al, 2008;Cho et al, 2009). The physical methods are based on the difference in size, density, aspect ratio, magnetic properties between the impurities and the CNTs.…”

Section: Purification and Puritymentioning

confidence: 99%

Processing Carbon Nanotubes

Vigolo¹,

Hérold²

2011

Carbon Nanotubes - Synthesis, Characterization, Applications

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A simple and highly effective process for the purification of single-walled carbon nanotubes synthesized with arc-discharge

Cited by 28 publications

References 18 publications

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

The Role of Iron Impurities in the Toxic Effects Exerted by Short Multiwalled Carbon Nanotubes (MWCNT) in Murine Alveolar Macrophages

Processing Carbon Nanotubes

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