Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography

Lazarević, Slavica; Janković-Čaštvan, Ivona; Onjia, Antonije; Krstić, Jugoslav; Janaćković, Djordje; Petrović, Rada

doi:10.1021/ie200595n

Cited by 10 publications

(5 citation statements)

References 48 publications

(67 reference statements)

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“…A solution could lie in the deposition of Fe(III) oxyhydroxides on porous minerals, such as zeolites, bentonites and sepiolites. 5,7,8,[14][15][16][17] Sepiolite is a fibrous hydrated magnesium silicate 18,19 with a unit cell formula Mg 8 Si 12 O 30 (OH) 4 (H 2 O) 4 ·nH 2 O, n = 6−8. Their structures have blocks and channels running parallel to the fibre axis, which provide excellent potential for the retention of micropollutants from water.…”

Section: Introductionmentioning

confidence: 99%

The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

Ilić¹,

Lazarević²,

Rajakovic-Ognjanovic

et al. 2014

J Serb Chem Soc

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The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 °C through batch studies. The influence of the initial pH value, the initial As concentration, the contact time and the type of water on the sorption capacity was investigated. Two types of water were used, deionised and groundwater. The maximal sorption capacity for As(III) dissolved in deionised water was observed at an initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, while a significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g -1 for As(III) and 4.2 mg g -1 for As(V) in deionised water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results showed that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has the potential for application in water purification processes.

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Section: Introductionmentioning

confidence: 99%

The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

Ilić¹,

Lazarević²,

Rajakovic-Ognjanovic

et al. 2014

J Serb Chem Soc

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“…Via Gutmann’s approach, for example, Sreekanth et al (2018 ) assessed that the surface of melamine- and thiourea-derived graphitic carbon nitrides contain similar basic sites and fewer acidic sites. In the same way, Lazarević et al (2011 ) proved that the iron-modification of sepiolite surface did not effect a change in acid–base properties, as the

ratio remained almost the same as that for natural sepiolite.…”

Section: Resultsmentioning

confidence: 70%

Characterization of polar surface groups on siliceous materials by inverse gas chromatography and the enthalpy–entropy compensation effect

et al. 2023

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Surface-modified porous silica is a well-established composite material. To improve its embedding and application behavior, adsorption studies of various probe molecules have been performed using the technique of inverse gas chromatography (IGC). For this purpose, IGC experiments were carried out in the infinite dilution mode on macro-porous micro glass spheres before and after surface modification with (3-mercaptopropyl)trimethoxysilane. To provide information about the polar interactions between probe molecules and the silica surface, in particular, eleven polar molecules have been injected. In summary, the free surface energy for pristine silica (γStotal = 229 mJ/m2) and for (3-mercaptopropyl)trimethoxysilane-modified silica (γStotal = 135 mJ/m2) indicates a reduced wettability after surface modification. This is due to the reduction of the polar component of the free surface energy (γSSP) from 191 mJ/m2 to 105 mJ/m2. Simultaneously, with the reduction of surface silanol groups caused by surface modification of silica and, therefore, the decrease in polar interactions, a substantial loss of Lewis acidity was observed by various IGC approaches. Experiments with all silica materials have been conducted at temperatures in the range from 90°C to 120°C to determine the thermodynamic parameters, such as adsorption enthalpy (ΔHads) and adsorption entropy (ΔSads), using the Arrhenius regression procedure evaluating the IGC data. With the help of the enthalpy–entropy compensation, two types of adsorption complexes are assumed between polar probe molecules and the silica surface because of different isokinetic temperatures. Identical adsorption complexes with an isokinetic temperature of 370°C have been assigned to alkanes and weakly interacting polar probes such as benzene, toluene, dichloromethane, and chloroform. Polar probe molecules with typical functional groups such as OH, CO, and CN, having the ability to form hydrogen bonds to the silica surface, exhibit a lower isokinetic temperature of 60°C. Quantum chemical calculations of the probe molecules on a non-hydroxylated and hydroxylated silica cluster supported the formation of hydrogen bonds in the case of a strong polar adsorption complex with a bonding distance of 1.7 nm–1.9 nm to the silica surface.

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“…According to literature, one of the main advantages of this technique in relation to others employed to analyze the superficial properties of a solid, is the easy sample preparation. 9 In literature, this technique has previously employed to successfully characterize the surface of a wide range of solid materials, such as sepiolite, 10 β-zeolite, 11 chitosan composites 12 o Ni-based catalysts. 13 Therefore, the objective of this work is to characterize a natural zeolite (clinoptilolite) employing IGC technique, to assess its potential as adsorbent for the removal of strategic metals from aqueous solutions at low compositions.…”

Section: One Of the Most Used Techniques To Analyze The Surface Chemis-mentioning

confidence: 99%

“…The combination of Equations (6), (8), and (9), when using nalkanes as probes, lead to Equation (10). Therefore, the plot of R.T.ln…”

Section: Igc Basismentioning

confidence: 99%

Characterization of a natural zeolite with inverse gas chromatography to assess its feasibility as adsorbent

Díez

Gómez

Rodrı́guez

et al. 2020

Env Prog and Sustain Energy

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In this work, the dispersive and specific components of the surface energy of clinoptilolite have been obtained by means of IGC technique with the aim of assessing its potential as adsorbent to remove metallic cations from aqueous solutions. The obtained values of the dispersive component range from 22 to 36 mJ/m2, in agreement with the fact that clinoptilolite removal of metal ions takes place mainly due to physisorption. In relation to acid–base properties, the acidic and basic constants of clinoptilolite were found to be KA = 52.4 and KD = 1.5, indicating that this solid is adequate for the removal of metallic cations from aqueous solutions due its acidic surface character.

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Surface Characterization of Iron-Modified Sepiolite by Inverse Gas Chromatography

Cited by 10 publications

References 48 publications

The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

Characterization of polar surface groups on siliceous materials by inverse gas chromatography and the enthalpy–entropy compensation effect

Characterization of a natural zeolite with inverse gas chromatography to assess its feasibility as adsorbent

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