The HSAB concept as a means to interpret the adsorption of metal ions onto activated carbons

Alfarra, Ahmad; Frąckowiak, Elżbieta; Béguin, François

doi:10.1016/j.apsusc.2003.12.033

Cited by 183 publications

(100 citation statements)

References 30 publications

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“…The adsorption of most metal cations on oxidized activated carbons appears to occur by ion exchange with the surface acid groups of the carbon [1,2,6,15]. This would result in a displacement of protons from the surface acid functional groups.…”

Section: Adsorption Of Metal Ionsmentioning

confidence: 95%

“…Hence, the adsorption mechanism in this case can be considered, more appropriately, as ''proton exchange with formation of surface metal complexes". For hexa-aquo cations, [M(H 2 O) 6 ] n+ , the adsorption mechanism may be either by inner-sphere (IS) or by outer-sphere (OS) surface metal complex formation, as illustrated for a divalent hexa-aquo cation in the respective schemes shown in Figs. 1 and 2.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanisms can be: by ion exchange and/or formation of surface metal complexes, mainly operating on the acidic surface oxygen functionalities; by adsorption on electron-rich regions within the graphene layers, acting as Lewis basic sites [2][3][4][5][6]; and by surface precipitation, which can occur under certain experimental conditions. This last mechanism removes metal cation from water but cannot be strictly considered an adsorption mechanism.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Adsorption mechanisms of metal cations from water on an oxidized carbon surface

Moreno‐Castilla

Álvarez-Merino

Pastrana‐Martínez

et al. 2010

Journal of Colloid and Interface Science

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Section: Adsorption Of Metal Ionsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Adsorption mechanisms of metal cations from water on an oxidized carbon surface

Moreno‐Castilla

Álvarez-Merino

Pastrana‐Martínez

et al. 2010

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…In general, the ligand binding preferences of complex multifunctional systems can be predicted by using reactivity descriptors based on the hard and soft acid and base (HSAB) theory. This has been demonstrated for extended carboneous systems [166][167][168][169][170][171][172][173] and other surfaces [174,175].…”

Section: Discussionmentioning

confidence: 88%

Transition metal and nitrogen doped carbon nanostructures

Stoyanov

Titov

Král

2009

Coordination Chemistry Reviews

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“…The type of nitrogen-containing functional groups formed on AC remains unclear; a nitrogen atom is more electronegative than a carbon atom, similar to an oxygen atom (Alfarra et al, 2004). Water molecules tend to be adsorbed onto the polar atoms.…”

Section: Effect Of Chemical Properties Of Activated Carbons On Dox Admentioning

confidence: 99%

Adsorption of 1,4-Dioxane from Aqueous Solutions onto Various Activated Carbons

Fukuhara

Iwasaki

Hasegawa

et al. 2011

J. of Wat. & Envir. Tech.

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The behavior of the adsorption of 1,4-dioxane (DOX) in water onto eight different activated carbons (ACs) was studied. All adsorption isotherms obtained using batch-type adsorption measurements, were found to fit a Freundlich equation. The amount adsorbed at an equilibrium concentration of 50 µg/L (q 50 ) was obtained, and its correlation with microporosity and chemical properties of each AC was examined. The AC prepared from sawdust by direct activation adsorbed the most DOX (410 µg/g), while adsorption in the other ACs were in the range of 4.3 -71.1 µg/g. No practical influence of specific surface area on the adsorption of DOX was found. We observed that log q 50 mostly decreased linearly with an increase in mean pore diameter. The concentrations of acidic surface oxides and nitrogen in the ACs affected the hydrophilicity of the adsorbent and impaired q 50 . It was assumed that the main factor for the adsorption of DOX at trace concentration in water was surface chemistry rather than the microporosity of AC.Keywords: activated carbon, adsorption, 1,4-dioxane INTRDUCTIONThe primary applications of 1,4-dioxane (DOX) include its use as an industrial solvent for paints, a surface-treating agent for artificial leather, and as a stabilizer for organochlorine solvents. Large-scale consumption of the chemical leads to environmental pollution. Because of its carcinogenicity, the 2003 World Health Organization (WHO) guidelines for drinking-water quality have recommended a maximum DOX concentration of 0.05 mg/L. In Japan, the DOX standard value for drinking water was set at 0.05 mg/L in 2004, and the same value was established as an environmental quality standard for aquatic environments in 2009. Technology to reduce DOX concentrations in water down to several tenths of a microgram per liter is needed to minimize the effects of DOX on human health. Activated carbon (AC) is widely used for the removal of hydrophobic organic compounds in water. The operation of AC adsorption processes is generally easy, and their performance is reliable. It can be applied to various scales of a treatment plant. In addition, ensuring safety is easier because target compounds are removed by mass transfer. However, it is known that DOX is a hydrophilic compound and is miscible with water in all proportions. The fact suggests that the adsorbability of DOX onto AC is qualitatively low. Therefore, no concrete data for DOX adsorption onto AC has been reported to date. Exploring the adsorption behavior is useful in developing effective treatment technologies for DOX removal. In general, the adsorptive properties of

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The HSAB concept as a means to interpret the adsorption of metal ions onto activated carbons

Cited by 183 publications

References 30 publications

Adsorption mechanisms of metal cations from water on an oxidized carbon surface

Adsorption mechanisms of metal cations from water on an oxidized carbon surface

Transition metal and nitrogen doped carbon nanostructures

Adsorption of 1,4-Dioxane from Aqueous Solutions onto Various Activated Carbons

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