Removal of hexavalent chromium and metal cations by a selective and novel carbon adsorbent

Lalvani, Shashi B.; Wiltowski, Tomasz; Hübner, A.; Weston, Alan; Mandich, N. V.

doi:10.1016/s0008-6223(98)00102-x

Cited by 172 publications

(84 citation statements)

References 12 publications

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“…However, fullerenic soot can fill niche markets unavailable to conventional carbon black. These markets include serving as an adsorbent for hexavalent chromium and metal cations [132,133] and dioxins [83]. In aggregate, these applications could create a market large enough to absorb the production of as much soot as is presented here.…”

Section: Implications For Fullerene Price Andfullerenic Soot Industrymentioning

confidence: 97%

Combustion synthesis of fullerenes and fullerenic nanostructures

Goel

Hebgen

Sande

et al. 2002

Carbon

117

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Fullerenes are molecules comprised entirely of sp 2 -bonded carbon atoms arranged in pentagonal and hexagonal rings to form a hollow, closed-cage structure. Buckyballs, a subset which contains C 60 and C 70 , are single-shell molecules while fullerenic nanostructures can contain many shells and over 300 carbon atoms. Both fullerenes and nanostructures have an array of applications in a wide variety of fields, including medical and consumer products. Fullerenes were discovered in 1985 and were first isolated from the products of a laminar low-pressure premixed benzene/oxygen/argon flame operating at fuel-rich conditions in 1991. Flame studies indicated that fullerene yields depend on operating parameters such as temperature, pressure, residence time, and equivalence ratio. High-resolution transmission electron microscopy (HRTEM) showed that the soot contains nanostructures, including onions and nanotubes.Although flame conditions for forming fullerenes have been identified, the process has not been optimized and many flame environments of potential interest are unstudied. Mechanistic characteristics of fullerene formation remain poorly understood and cost estimation of large-scale production has not been performed. Accordingly, this work focused on: 1) studying fullerene formation in diffusion and premixed flames under new conditions to identify optimal parameters; 2) investigating the reaction of fullerenes with soot; 3) positively identifying C 60 molecules in HRTEM by tethering them to carbon black; and 4) providing a cost estimation for industrial fullerenic soot production.Samples of condensable material from laminar low-pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography (HPLC) and HRTEM. The highest concentration of fullerenes in a flame was always detected just above the height where the fuel is consumed. The percentage of fullerenes in condensable material increases with decreasing pressure and the fullerene content of flames with similar cold gas velocities shows a strong dependence on length. A shorter flame, resulting from higher dilution or lower pressure, favors the formation of fullerenes rather than soot, exhibited by the lower amount of soot and precursors in such flames. This indicates a stronger correlation of fullerene consumption to soot levels than of fullerene formation to precursor concentration. The maximum flame temperature seems to be of minor importance in formation. The overall highest amount of fullerenes was found for a surprisingly high dilution of fuel with argon. The HRTEM analysis showed an increase of the curvature of the carbon layers, and hence increased fullerenic character, with increasing distance from the burner up to the point of maximum fullerene concentration, after which it decreases, consistent with the HPLC analysis. The soot shows highly ordered regions that appear to have been cells of fullerenic nanostructure formation. The samples also included fullerenic nanostructures such as tubes and sp...

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Section: Implications For Fullerene Price Andfullerenic Soot Industrymentioning

confidence: 97%

Combustion synthesis of fullerenes and fullerenic nanostructures

Goel

Hebgen

Sande

et al. 2002

Carbon

117

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“…It has been also stressed that adsorption thermodynamics is drastically affected by the equilibrium pH of the solutions. Regardless of the equilibrium pH, adsorption of the heavy metals by a single adsorbent could be completed in a quite different contact time (Carrott et al, 1997;Lalvani et al, 1998;Farias et al, 2002;Perez-Candela et al, 1995). Taking into account that equilibration of metal ions uptake by activated carbons depends on the equilibrium pH, authors agreed (Lyubchik et al, 2003) with the statement (Carrott et al, 1997) that it would be appropriate to express adsorption results in terms of the final solution pH.…”

mentioning

confidence: 99%

Comparison of the Thermodynamic Parameters Estimation for the Adsorption Process of the Metals from Liquid Phase on Activated Carbons

Lyubchik¹,

Lyubchik²,

Lygina³

et al. 2011

Thermodynamics - Interaction Studies - Solids, Liquids and Gases

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“…Cr(VI) compounds are powerful oxidizing agents 5 , are irritating and corrosive, and appear to be much more toxic systemically than Cr(III) compounds, given similar amounts and solubilities 6 . Once ingested beyond the maximum concentration (0.1 mg/L), chromium can induce vomiting and hemorrhage 7 with its high toxicity attributed to its ease in passing through cell membranes. Endogenous reducing agents such as hydrogen peroxide (H 2 O 2 ), glutathione (GSH), and ascorbic acid can produce reactive intermediates such as Cr(V), Cr(IV), thiylradicals, hydroxyl radicals, and Cr(III) which disrupt membrane integrity leading to cellular dysfunction 8 .…”

Section: Introductionmentioning

confidence: 99%

Batch Adsorption Study and Kinetic Profile of Cr(VI) Using Lumbang (Aleurites moluccana)-Derived Activated Carbon-Chitosan Composite Crosslinked With Epichlorohydrin

Villarante¹,

Bautista²,

Sumalapao³

2017

Orient. J. Chem

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Batch adsorption of toxic Cr(VI) ion from an aqueous solution using lumbang (Aleurites moluccana) activated carbon-chitosan composite crosslinked with epichlorohydrin as an adsorbent was investigated. The adsorption experiments were performed at varying pH, agitation time, initial Cr(VI) ion concentration, temperature, and adsorbent dose. At an initial concentration of 60 ppm Cr(VI), the maximum adsorption was observed at pH 3, adsorbent dose of 3 g/L, contact time of 75 min, and temperature of 30 o C. Analysis of the experimental data using different kinetic models revealed that the biosorption phenomenon behaved under a pseudo second-order rate mechanism.

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Removal of hexavalent chromium and metal cations by a selective and novel carbon adsorbent

Cited by 172 publications

References 12 publications

Combustion synthesis of fullerenes and fullerenic nanostructures

Combustion synthesis of fullerenes and fullerenic nanostructures

Comparison of the Thermodynamic Parameters Estimation for the Adsorption Process of the Metals from Liquid Phase on Activated Carbons

Batch Adsorption Study and Kinetic Profile of Cr(VI) Using Lumbang (Aleurites moluccana)-Derived Activated Carbon-Chitosan Composite Crosslinked With Epichlorohydrin

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