Synergistic interactions between multi-walled carbon nanotubes and toxic hexavalent chromium

Gu, Hongbo; Rapole, Sowjanya B.; Huang, Yudong; Cao, Dongmei; Luo, Zhiping; Wei, Suying; Guo, Zhanhu

doi:10.1039/c2ta00550f

Cited by 122 publications

(64 citation statements)

References 69 publications

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“…However, for raw and modified CNTs, the maximum adsorption occurs at pH 4 and 3, respectively. [15,28]. Dichromate ions (Cr 2 O 2À 7 ) are the dominant species at lower pH, while at higher pH, only chromate (CrO 2À 4 ) ion exists in the solution.…”

Section: Effect Of Phmentioning

confidence: 99%

“…In addition to the aforementioned techniques, reduction of Cr(VI) to Cr(III) followed by Cr(III) adsorption on the adsorbent surface has also been reported to be an effective approach for the removal of Cr(VI) ions from water. The reduction is strongly dependent on the pH value and initial Cr(VI) concentration of the solution [12,28,29]. Various materials, such as Fe(II) [30,31], zero-valence Fe [32], zero-valence Al [33], polymers [34,35], and biomass [36,37] can be used for simultaneous adsorption and reduction of Cr(VI) ions to Cr(III) ions [29].…”

Section: Introductionmentioning

confidence: 99%

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Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Ihsanullah

Al-Khaldi

Abu-Sharkh

et al. 2016

Desalination and Water Treatment

175

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A B S T R A C TThe present study addresses the application of raw and modified carbon nanotubes (CNTs) and activated carbon (AC) for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Surfaces of both the adsorbents were modified by acid treatment. Nitric acid was used to remove impurities and to introduce carboxylic functional groups on the surfaces of CNTs and AC. Raw and modified adsorbents (CNTs and AC) were characterized by scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, and thermogravimetric analysis. The influence of adsorbent dosage, contact time, agitation speed, and solution pH were evaluated on the Cr(VI) removal efficiency using batch adsorption experiments. The optimum pH for maximum adsorption of Cr(VI) was found to be 3 and 4 for AC and CNTs, respectively. Modified and raw AC were able to remove 99 and 92% of Cr(VI) ions, respectively, at 75 mg adsorbent dosage, agitation speed of 200 rpm, initial Cr(VI) concentration of 1 mg/L, contact time of 4 h, and solution pH 3, while the removal of Cr(VI) ions recorded maximum values of 87 and 80% for modified and raw CNTs under same treatment conditions. However, acid modification of CNTs was found to have no major effect on the percentage removal of Cr(VI) ions at low adsorbent dosage. Adsorption capacities of both the adsorbents were determined using batch adsorption experiments and experimental data were described by Langmuir and Freundlich adsorption isotherm models. However, Langmuir isotherm model was able to best describe the adsorption of Cr(VI) ions on raw and modified forms of CNTs and AC. Maximum adsorption capacity (q e ) was found to be 2.024 and 1.805 mg/g for raw and modified AC, while 1.021 and 0.964 mg/g for raw and modified CNTs.

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Section: Effect Of Phmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Ihsanullah

Al-Khaldi

Abu-Sharkh

et al. 2016

Desalination and Water Treatment

175

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“…The pure Co 3 O 4 nanoakes (Fig. 29,30 The relative intensity ratio, I D /I G , depends on the structural characteristics of the carbon material. Fig.…”

Section: Measurementsmentioning

confidence: 99%

Rechargeable Co₃O₄ porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances

Qiu

et al. 2015

RSC Adv.

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Multi-walled carbon nanotubes intertwined with porous Co 3 O 4 nanoflakes (Co 3 O 4 /MWNT) have been hydrothermally synthesized to form a three dimensional network with superior electrical and ionic conductivity and tested as an anode material for lithium-ion batteries (LIBs). The electrochemical measurements on the Co 3 O 4 /MWNT composites demonstrated a reversible capacity of 708 mA h g À1 after 100 cycles at a current density of 100 mA g À1 and discharge capacities of 773, 805, 698, and 491 mA h g À1 at current densities of 100, 200, 400, and 800 mA g À1 , respectively. The superior cycling and rate performances were attributed to the formed network structure, in which the entanglement and flexibility of MWNTs buffered the volume change of Co 3 O 4 during the charge-discharge process and improved the electrical conductivity of the electrode.

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“…25 Various metal and metal oxide nanoparticles (NPs) on graphene or multi-walled carbon nanotube (MWCNTs) surfaces have been explored for direct catalytic glucose oxidation. [26][27][28][29] Among all, NiO materials, because of their excellent catalytic activity, biocompatibility, low toxicity and low cost, are highly suitable for the fabrication of nonenzymatic glucose sensors. [30][31][32][33] Herein, we report facile, eco-friendly, rapid, scalable and economical route to synthesize NiO decorated graphene-MWCNTs ternary nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

Nickel-oxide multiwall carbon-nanotube/reduced graphene oxide a ternary composite for enzyme-free glucose sensing

2016

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We report the solvent-free method of preparation for NiO-carbon nanotube/graphene ternary composite using nickel formate as a green precursor via thermal decomposition method. In this ternary composite, NiO with an average particle size of 7 nm is regularly decorated on the surface of conductive carbon matrices network such as MWCNTs and reduced graphene oxide (rGO). Here rGO serves as an ideal support for uniform distribution of NiO nanoparticles and also functions as an efficient transducer material, whereas, MWCNTs acts as a spacer between rGO, which enhances the electrical conductivity and accessibility of active reaction sites for direct glucose oxidation. The electrochemical performances are evaluated by cyclic voltammetry and amperometric techniques. Under the optimal conditions, the 20 wt. % NiO-MWCNT/rGO/GCE exhibits the sensitivity of 4223.3 µA cm −2 mM −1 and detection limit of 0.92 µM over a linear glucose concentration range upto 19 mM. Furthermore, the constructed sensor is effectively employed to detect glucose in real human blood serum sample with adequate results. The modified 20 wt.% NiO-MWCNT/rGO/GCE also shows a high sensitivity, greater selectivity, excellent reproducibility and long-term stability.

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Synergistic interactions between multi-walled carbon nanotubes and toxic hexavalent chromium

Cited by 122 publications

References 69 publications

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Rechargeable Co₃O₄ porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances

Nickel-oxide multiwall carbon-nanotube/reduced graphene oxide a ternary composite for enzyme-free glucose sensing

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Synergistic interactions between multi-walled carbon nanotubes and toxic hexavalent chromium

Cited by 122 publications

References 69 publications

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Rechargeable Co3O4 porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances

Nickel-oxide multiwall carbon-nanotube/reduced graphene oxide a ternary composite for enzyme-free glucose sensing

Contact Info

Product

Resources

About

Rechargeable Co₃O₄ porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances