An investigation of Cu(II) adsorption by raw and acid-activated bentonite: A combined potentiometric, thermodynamic, XRD, IR, DTA study

Eren, Erdal; Afsin, B.

doi:10.1016/j.jhazmat.2007.06.040

Cited by 206 publications

(96 citation statements)

References 41 publications

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“…The clays-Cu interactions occurred spontaneously and were accompanied by a decrease in Gibbs free energy (ΔG < 0). The degree of spontaneity was found to decline as the process temperature rose, ranging from −16.6 to −27.9 kJ.mol -1 for the temperature range between 273 and 348 K. Adsorption and ion exchange of Cu(II) on different clays had already been reported as endothermic [23][24][25][26][27][28] , as shown in Table 6. It was likely that adsorption of Cu(II) ions on clay surface require an activation energy and rise in temperature helped more Cu(II) ions to overcome this energy barrier and get attached to the surface 23 .…”

Section: Adsorption Thermodynamicsmentioning

confidence: 90%

Cu(II) adsorption on modified bentonitic clays: different isotherm behaviors in static and dynamic systems

2011

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Cu (II) removal equilibrium from aqueous solutions using calcined clays "Bofe" and "Verde-lodo" has been studied by batch and fixed-bed in static and dynamic systems, respectively. Analyses were performed for physicochemical characterization of clays using the techniques: X-ray fluorescence (XRF), thermogravimetry (TG), N 2 adsorption (BET) and Cationic Exchange Capacity (CEC). Batch experiments were performed at a constant temperature, adjusting the pH of the solution in contact with clays. Adsorption assays in fixed bed were conducted at the flow rate determined through mass transfer zone (MTZ). Langmuir and Freundlich models were adjusted to equilibrium data. The results of characterization indicated that the temperature of 500 °C is best suited for the calcination of the clays. The maximum adsorption capacity was higher for dynamic system than fixed bed compared to static system, enhancing from 0.0748 to 0.1371 and from 0.0599 to 0.22 mmol.g -1 of clay for "Bofe" and "Verde-lodo", respectively.

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Section: Adsorption Thermodynamicsmentioning

confidence: 90%

Cu(II) adsorption on modified bentonitic clays: different isotherm behaviors in static and dynamic systems

2011

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“…3. The absorption band at 3621 cm −1 was due to the stretching vibration of structural OH group (Al-OH) of Na + -bentonite; the bands at 3432 and 1631 cm −1 corresponded to the stretching and bending vibrations of H 2 O, respectively; the band at 1045 cm −1 represented the stretching vibration of Si-O, while the band corresponding to Al-Al-OH bending vibration was observed at 921 cm −1 ; the band at 790 cm −1 implied quartz admixture in the samples; the bands at 528 and 466 cm −1 were associated with the bending vibrations of Si-O-Mg and Si-O-Fe, respectively (Eren and Afsin, 2008;Liu et al, 2010;Wang et al, 2009;Yuan et al, 2008). After clay was pillared, the amount of OH groups (H-OH and Al-OH) increased markedly on account of the much stronger absorption at 1631, 3432 and 3621 cm −1 .…”

Section: Resultsmentioning

confidence: 97%

Catalytic wet peroxide oxidation of 4-chlorophenol over Al-Fe-, Al-Cu-, and Al-Fe-Cu-pillared clays: Sensitivity, kinetics and mechanism

Zhou

Zhang

et al. 2014

Applied Clay Science

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Al-Fe-, Al-Cu-, and Al-Fe-Cu-PILCs were synthesized, characterized and tested in the catalytic wet peroxide oxidation of 4-chlorophenol (4-CP). An apparent induction period followed by a rapid oxidation was observed during the Fenton-like reaction, and the whole reaction could be modeled well using a Fermi's kinetic equation (R 2 = 0.9938~0.9993). The generation of hydroxyl radicals (HO • ) from surface-catalyzed decomposition of H 2 O 2 was the oxidation cause whereas the dissolution of active metals was its result. Accordingly, induction period was the cause of heterogeneous surface activation (catalysis or modification) for more HO • formed by decreasing pH. 4-CP oxidation proceeded via 4-chlorocatechol (major) and hydroquinone (minor) pathways, along the formation of main intermediate (5-chloro-1,2,4-benzentriol). Finally besides CO 2 , H 2 O and Cl − two main compounds (I and II) formed, where the former was identified as 2,4-dioxopentanedioic acid whereas the latter as ferric-oxalate complex. There were marked structural and active differences between Al-Fe-PILC and Al-Cu-PILC in which compared to the latter, the former possessed higher SSA and activity but its optimal calcination temperature was lower and the induction time was also longer. In addition, compound II accounted for a considerable proportion in Al-Fe-PILC system whereas compound I was almost only component in Al-Cu-PILC system.

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“…All FTIR spectra showed the presence of similar peaks in the range of 1100-600 cm -1 . In this range, there are peaks related to stretching vibration of Si-O groups, Al-O-Si and Si-O-Si bending vibrations and Al-O and Si-O out of plane vibrations of bentonite framework structure [24]. Thus, these FTIR spectra show the structural stability of bentonite after modification with Ag and CTAB [17].…”

Section: Antibacterial Assaymentioning

confidence: 85%

“…The XRD patterns shows that the major phase is montmorillonite (M) and other minor phases present in the sample are illite (I), quartz (Q) and kaolinite (K) [23]. There were no changes in the XRD patterns of both samples indicating that the structure of bentonite was stable after loaded with Ag cations [24]. Characterizations of both samples were further performed by elemental analysis qualitatively using EDX (Fig.…”

Section: Antibacterial Assaymentioning

confidence: 99%

Antibacterial Activity of Cetyltrimethylammonium Bromide Modified Silver-Bentonite

Malek

Azalisa

Lin

2016

MATEC Web of Conferences

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Abstract. Organo-Ag-bentonite was prepared by the attachment of cationic surfactant cetyltrimethylammonium bromide on silver(A)g-exchanged bentonite. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray (EDX) analysis and antibacterial assay was performed against Escherichia coli in different percentage of saline solutions through minimum inhibition concentration (MIC) method. Organo-Ag-bentonite showed higher antibacterial activity than organo-bentonite and Ag-bentonite especially in saline solution suggesting that the precipitation of AgCl in the presence of Ag-bentonite in saline solution could be avoided by the attachment of cationic surfactant on Ag-bentonite surfaces, hence increased their antibacterial activity.

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An investigation of Cu(II) adsorption by raw and acid-activated bentonite: A combined potentiometric, thermodynamic, XRD, IR, DTA study

Cited by 206 publications

References 41 publications

Cu(II) adsorption on modified bentonitic clays: different isotherm behaviors in static and dynamic systems

Cu(II) adsorption on modified bentonitic clays: different isotherm behaviors in static and dynamic systems

Catalytic wet peroxide oxidation of 4-chlorophenol over Al-Fe-, Al-Cu-, and Al-Fe-Cu-pillared clays: Sensitivity, kinetics and mechanism

Antibacterial Activity of Cetyltrimethylammonium Bromide Modified Silver-Bentonite

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