Study of the removal of mercury(II) and chromium(VI) from aqueous solutions by Moroccan stevensite

Benhammou, A.; Yaacoubi, Abdelrani; Nibou, L.; Tanouti, B.

doi:10.1016/j.jhazmat.2004.09.023

Cited by 51 publications

(23 citation statements)

References 26 publications

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“…The Dubinin-Radushkevich isotherm, apart from being an analogue of the Langmuir isotherm, is more general than Langmuir isotherm because it does not apply to the homogeneous surfaces or surfaces of constant adsorption potential. The Dubinin-Radushkevich isotherm as expressed by Benhammou et al [24] is show in equation 17.…”

Section: Dubinin-radushkevich (D-r) Isothermmentioning

confidence: 99%

Biosorption of amaranth red in aqueous solution onto treated and untreated lignocellulosic materials (pineapple peelings and coconut shells)

Ndifor-Angwafor¹,

Tiotsop²,

Tchuifon³

et al. 2017

JMES

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The removal of amaranth red dye from aqueous solution by untreated and treated pineapple peelings and coconut shells with phosphoric acid was studied in batch mode at room temperature. The study highlighted several parameters such as the contact time, the mass of the adsorbent, the pH of the solution, and the initial concentration of the dye. The results showed that the removal of dyes by the bioadsorbents depended on the pH and the initial concentration of the adsorbate. The adsorption capacity increased with increasing amaranth red dye concentration and the mass of the bioadsorbent. It was also established that maximum adsorption took place at pH = 2 for different adsorbents. The treated raw materials have greater surface area than the untreated materials. In order to deduce the adsorption mechanism, four simplified kinetic models were investigated. The kinetic data were well represented by the pseudo second order kinetic model giving high correlation coefficients R² values for all the biosorbents suggesting that chemisorption was the rate determining step. An equilibrium study of the adsorption process also showed that the Langmuir model best described the adsorption on all the biosorbents. The values of energy obtained from the Temkin isothermare also positive, this shows that the adsorption process isexothermic. These results indicate that pineapple peelings and coconut shells have a high potential as adsorbents for removing amaranth red dye from aqueous solution

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Section: Dubinin-radushkevich (D-r) Isothermmentioning

confidence: 99%

Biosorption of amaranth red in aqueous solution onto treated and untreated lignocellulosic materials (pineapple peelings and coconut shells)

Ndifor-Angwafor¹,

Tiotsop²,

Tchuifon³

et al. 2017

JMES

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“…This result indicates that increasing the Cr(III) concentration reduces the diffusion of Cr(III) in the solution. The initial sorption rate, h, has been widely used for the evaluation of sorption rates [19]. In this study, the value of h is 0.527-1.647 mg%g -1 %min -1 .…”

Section: Kinetic Modelsmentioning

confidence: 99%

Biosorption of Cr(III) from aqueous solution by freeze-dried activated sludge: Equilibrium, kinetic and thermodynamic studies

Yao

Zhang

et al. 2010

Front. Environ. Sci. Eng. China

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Batch biosorption experiments were conducted to remove Cr(III) from aqueous solutions using activated sludge from a sewage treatment plant. An investigation was conducted on the effects of the initial pH, contact time, temperature, and initial Cr(III) concentration in the biosorption process. The results revealed that the activated sludge exhibited the highest Cr(III) uptake capacity (120 mg%g -1 ) at 45°C, initial pH of 4, and initial Cr(III) concentration of 100 mg%L -1 . The biosorption results obtained at various temperatures showed that the biosorption pattern accurately followed the Langmuir model. The calculated thermodynamic parameters, ΔG o ( -0.8--4.58 kJ%mol -1 ), ΔH o (15.6-44.4 kJ%mol -1 ), and ΔS o (0.06-0.15 kJ%mol -1 %K -1 ) clearly indicated that the biosorption process was feasible, spontaneous, endothermic, and physical. The pseudo first-order and second-order kinetic models were adopted to describe the experimental data, which revealed that the Cr(III) biosorption process conformed to the second-order rate expression and the biosorption rate constants decreased with increasing Cr (III) concentration. The analysis of the values of biosorption activation energy (E a = -7 kJ%mol -1 ) and the intraparticle diffusion model demonstrated that Cr(III) biosorption was film-diffusion-controlled.

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“…Both montmorillonite and vermiculite are typical for 2:1 expandable clay minerals, which consist of two tetrahedral silica sheets with a central octahedral alumina or magnesia layer [14]. The interaction mechanism between natural clay minerals and metal ions occurs not only by cation exchange, which is a consequence of the permanent negative charge in the interlayer, but also by the formation of innerand outer-sphere complexes involving silanol or aluminol groups at the particle edges [12,15,16]. Numerous investigations have been devoted to chemically modified clays for the removal of Hg(II) in recent years, of which the grafting of thiol group ( SH) to clays have been extensively studied and confirmed to be effective adsorbents [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Comparative study of Hg(II) adsorption by thiol- and hydroxyl-containing bifunctional montmorillonite and vermiculite

Tran

Zhu

et al. 2015

Applied Surface Science

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Study of the removal of mercury(II) and chromium(VI) from aqueous solutions by Moroccan stevensite

Cited by 51 publications

References 26 publications

Biosorption of amaranth red in aqueous solution onto treated and untreated lignocellulosic materials (pineapple peelings and coconut shells)

Biosorption of amaranth red in aqueous solution onto treated and untreated lignocellulosic materials (pineapple peelings and coconut shells)

Biosorption of Cr(III) from aqueous solution by freeze-dried activated sludge: Equilibrium, kinetic and thermodynamic studies

Comparative study of Hg(II) adsorption by thiol- and hydroxyl-containing bifunctional montmorillonite and vermiculite

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