A kinetic and equilibrium study of zinc removal by Brazilian bentonite clay

Araújo, Alexandra M.; Gimenes, Marcelino Luiz; Barros, Maria Angélica Simões Dornellas de; Silva, Meuris Gurgel Carlos da

doi:10.1590/s1516-14392012005000148

Cited by 17 publications

(7 citation statements)

References 17 publications

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“…XRD diffractograms indicated characteristic peaks of Na-montmorillonite at 2θ 7.57°, 20°, and 28°, respectively. 27,28 The peak at 2θ = 20°, characteristic for nonbasal reflections (02, 11), was present for all nanocomposites, indicating that the crystalline layered structure was not affected by the modification process. 29,30 The 2θ value at 28°was attributed to (005) reflection.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

A Novel Bioresidue to Compatibilize Sodium Montmorillonite and Linear Low Density Polyethylene

Høgsaa

Fini

Christiansen

et al. 2018

Ind. Eng. Chem. Res.

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Despite the improved thermal stability and mechanical properties of polymer−clay nanocomposites compared to pure polymeric materials, creating nanocomposites with enhanced thermomechanical properties requires a good compatibility and dispersion of the clay within the polymeric matrix. This paper introduces a bioresidue extracted from waste biomass to modify montmorillonite clay to compatibilize it with linear low density polyethylene (LLDPE). The biomodified clay was compounded, melt blended, and injection molded with LLDPE, and the thermomechanical properties of the resulting nanocomposites were investigated with oscillatory rheometry, thermogravimetric analysis, X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, and transmission electron microscopy to assess the compatibility of the biomodified clay and the polymer. The structure of the biomodified clay ranged from partially intercalated to fully exfoliated. Hansen solubility parameters indicate that almost all of the identified compounds in the bioresidue are soluble with polyethylene. Density functional-based modeling showed a trade-off between electrostatic screening and dispersion interactions affecting the overall interlayer spacing in polymer−clay nanocomposites.

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Section: ■ Results and Discussionmentioning

confidence: 92%

A Novel Bioresidue to Compatibilize Sodium Montmorillonite and Linear Low Density Polyethylene

Høgsaa

Fini

Christiansen

et al. 2018

Ind. Eng. Chem. Res.

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“…The parameters obtained for the non-linear Langmuir-Freundlich equations are shown in Table V. Compared to some other adsorbents, such as Bofe clay with a q max of 4.39 mg.g -1 [66], and a lateritic clay with a q max of 5.60 mg.g -1 [67], both for heavy metals adsorption from aqueous solution, the values for maximum adsorption capacity for Zn 2+ obtained in this study were superior. Table V shows the calculated values of the Langmuir and Freundlich model parameters.…”

Section: Source Dfmentioning

confidence: 73%

Removal of Pb2+ and Zn2+ using modified Chocolate B clay: a study using statistical analysis, equilibrium isotherms, and adsorption kinetics

2021

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In this work, natural and thermally modified Chocolate B clays were used for batch adsorption of Pb 2+ and Zn 2+ from an aqueous solution. The materials were characterized by X-ray diffraction, X-ray fluorescence spectroscopy, nitrogen adsorption, and cation exchange capacity. The tests were performed in a finite bath following a 2 2 factorial design, with the variables: pH and initial concentrations of metal. Results revealed that the thermal treatment caused alterations on the Chocolate B clay structure and decreased the specific surface area. Affinities between Pb 2+ or Zn 2+ and Chocolate B clay were found with adsorption capacities up to 3.36 and 3.72 mg.g -1 , respectively. The maximum adsorption capacities were 6.79 mg.g -1 for Pb 2+ and 3.35 mg.g -1 for Zn 2+ using thermally activated clay. The Langmuir and Freundlich models were used for the adsorption equilibrium analysis, and the Langmuir model provided the best fit for sorption isotherms. The adsorption kinetics was evaluated by two models: pseudo-first-order and pseudo-second-order. The pseudo-first-order kinetic model represented well the mechanism of interaction involved during Pb 2+ adsorption into the pores of the clay. However, the two models represented well the mechanism of interaction of Zn 2+ adsorption into the pores of the clay.

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“…In the present study, we observed a clay expansion of approximately 2-to 3-fold within the core tube system. The negative charge on the structure of clay minerals attracts cationic metals (Babel & Kurniawan, 2003), and thus clay has been shown to be effective for removing Zn and other metal ions (e.g., Pb 2+ , Al 3+ ) from aqueous solutions (Brummer, 1986;Pereira de Araujo et al, 2013;Ryan et al, 2009;Shi et al, 2009). Bothe and Brown (1999) evaluated bentonite clay for Zn removal and found that its sorption capacity was 52.9 mg of Zn 2+ g −1 bentonite and fit the Langmuir model.…”

Section: Effects Of Capping Materials On Zn Fluxmentioning

confidence: 99%

Evaluation of Capping Materials to Reduce Zinc Flux from Sediments in a Former Mining Pit Lake

Cervi

Hudson

Rentschler

et al. 2021

Enviro Toxic and Chemistry

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Wilson Mine is a former vanadium mine site located in the Ouachita Mountains near Hot Springs, Arkansas. The site, which drains via two streams to Lake Catherine, has undergone extensive reclamation to significantly reduce groundwater and surface water contact with mine spoils. One of the streams passes through a former mine pit forming East Wilson Pond, and flux from pit lake sediments can result in elevated metal, that is, zinc (Zn), concentrations in overlying water. To mitigate potential risks, an investigation was conducted to evaluate the efficacy of capping materials for partitioning Zncontaminated sediments from overlying water in East Wilson Pond. A 28-day laboratory study compared the effectiveness of capping materials including combinations of limestone, bentonite clay, and gravel for mitigating Zn flux, including under reasonable worst-case conditions (pH 5.5) encountered in the hypolimnion. Dissolved Zn was monitored over time in overlying water and in sediment porewaters within untreated controls and within the capping layer of treated systems. The use of limestone and/or bentonite clay improved buffering capacity compared to the noncapped control, and pH declined gradually but only modestly in the overlying water and porewater of all treated systems. Concentrations of Zn in overlying water of the noncapped control increased from approximately 30 to 100 µg/L during the study period, while concentrations in the overlying water and porewater of systems containing capping materials remained low (10-30 µg/L). The results demonstrated the effectiveness of the capping materials for neutralizing pH and reducing Zn flux, and a three-layer cap consisting of limestone (top) + bentonite clay (middle) + gravel (bottom) was determined to be most effective. These results were used to inform the selection of materials for the application of a cap to reduce Zn flux from the pit lake sediments.

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A kinetic and equilibrium study of zinc removal by Brazilian bentonite clay

Cited by 17 publications

References 17 publications

A Novel Bioresidue to Compatibilize Sodium Montmorillonite and Linear Low Density Polyethylene

A Novel Bioresidue to Compatibilize Sodium Montmorillonite and Linear Low Density Polyethylene

Removal of Pb2+ and Zn2+ using modified Chocolate B clay: a study using statistical analysis, equilibrium isotherms, and adsorption kinetics

Evaluation of Capping Materials to Reduce Zinc Flux from Sediments in a Former Mining Pit Lake

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