Kinetics and thermodynamics of Eu(III) and U(VI) adsorption onto palygorskite

Zhu, Yongming; Chen, Tianhu; Li, Haibo; Xu, Bin; Xie, Jingjing

doi:10.1016/j.molliq.2016.03.034

Cited by 66 publications

(20 citation statements)

References 55 publications

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“…Figure 3 show the SEM images of Py (A) and MPy (B). It can be observed that the natural pyrite crystal has a large size with smooth surfaces, while the modified pyrite has abundant inhomogeneous pores, resulting in modified pyrite with a higher porosity and higher specific surface area than natural pyrite, which confirms the result obtained from previous studies [31][32][33]. Based on previous studies by the authors, the sorption process of Hg(II) by MPy can be fitted by the Langmuir model and the Freundlich model.…”

Section: Structure and Property Of Modified Pyritesupporting

confidence: 85%

Mercury Removal from Aqueous Solutions Using Modified Pyrite: A Column Experiment

et al. 2019

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Modified pyrite (MPy), which was obtained from calcination in an N2 atmosphere, was used as a sorbent for removing Hg(II) from aqueous solutions. Fixed-bed column experiments were conducted to determine the Hg(II) removal ability of MPy from aqueous solutions. MPy was found to be much better than natural pyrite for mercury removal. The concentration of Hg(II) in effluents was much lower than that of the emission standard used for Hg wastewater in China (0.05 mg/L), and the removal efficiency of Hg(II) was greater than 99% before breakthrough. When the capacity was 3274 times the column bed volume (1 bed volume = 25.12 cm3), the column breakthrough and the sorption amount of Hg(II) were 54.44 mg/g. The Hg(II) content in the used MPy sorbent was up to 24.79%. The mechanism was analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), field emission transmission electron microscopy (FE-TEM), and X-ray Photoelectron Spectroscopy (XPS). The main mechanism of Hg(II) removal by MPy was the chemical reactions between mercury ions and mineral fillers, and HgS precipitated on the surface of MPy to remove Hg(II). The reaction was also accompanied by surface complexation and adsorption. The results of this work show that MPy can be used as a sorbent for continuous Hg(II) removal.

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Section: Structure and Property Of Modified Pyritesupporting

confidence: 85%

Mercury Removal from Aqueous Solutions Using Modified Pyrite: A Column Experiment

et al. 2019

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“…The calculated q e agreed with the experimental data (q exp ). These results indicate that adsorption in palygorskite samples can be determined mainly by chemisorption, involving the sharing or transfer of electrons [103,104]…”

Section: Adsorption Kineticsmentioning

confidence: 89%

Adsorption Behavior of Acid-Treated Brazilian Palygorskite for Cationic and Anionic Dyes Removal from the Water

et al. 2021

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The effect of acid treatment on the adsorptive capacity of a Brazilian palygorskite to remove the crystal violet (CV) and congo red (CR) dyes was investigated. The raw palygorskite was acid-treated by different HCl solutions (2, 4, and 6 mol/L). The modifications on the palygorskite structure were investigated using X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy, N2 adsorption/desorption, and thermogravimetric and differential thermal analysis. The efficiency of CV and CR adsorption was investigated, and the effect of the initial concentration, contact time, pH, and adsorbent amount was analyzed. The results revealed that CV adsorption in the acid-treated palygorskite was higher than that of the raw material. A Langmuir isotherm model was observed for the adsorption behavior of CV, while a Freundlich isotherm model was verified for the CR adsorption. A pseudo-second-order model was observed for the adsorption kinetics of both dyes. The higher CV adsorption capacity was observed at basic pH, higher than 97%, and the higher CR removal was observed at acidic pH, higher than 50%. The adsorption parameters of enthalpy (ΔH), entropy (ΔS), and Gibbs energy (ΔG) were evaluated. The adsorption process of the CV and CR dyes on the raw and acid-treated Brazilian palygorskite was predominantly endothermic and occurred spontaneously. The studied raw palygorskite has a mild-adsorption capacity to remove anionic dyes, while acid-treated samples effectively remove cationic dyes.

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“…The peak at 3649 cm −1 refers to the −OH vibrations [12,35]. The characteristic absorbance peak at 3649 cm −1 of MPy-600-Hg(II) is higher, which can be ascribed to the formation of ferric hydroxide from the dissolution of iron, and more Hg(OH) 2 is formed by attracting more −OH molecules to Hg(II) [36]. The relative intensities of the MPy-600-Hg(II) peaks at 483 cm −1 and 1076 cm −1 are lower, which probably suggests that MPy-600 reacted with Hg(II) [37].…”

Section: The Ftir and Raman Spectramentioning

confidence: 99%

Green Preparation of Nanoporous Pyrrhotite by Thermal Treatment of Pyrite as an Effective Hg(Ⅱ) Adsorbent: Performance and Mechanism

Lü

Chen

et al. 2019

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The removal of Hg(II) from aqueous solutions by pyrrhotite derived from the thermal activation of natural pyrite was explored by batch experiments. The adsorption isotherms demonstrated that the sorption of Hg(II) by modified pyrite (MPy) can be fitted well by the Langmuir model. The removal capacity of Hg(II) on MPy derived from the Langmuir model was determined to 166.67 mg/g. The adsorption process of Hg(II) on MPy was well fitted by a pseudo-second-order model. The sorption of Hg(II) on MPy was a spontaneous and endothermic process. The removal of Hg(II) by MPy was mainly attributed to a chemical reaction resulting in cinnabar formation and the electrostatic attraction between the negative charges in MPy and positive charges of Hg(II). The results of our work suggest that the thermal activation of natural pyrite is greatly important for the effective utilization of ore resources for the removal of Hg(II).

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Kinetics and thermodynamics of Eu(III) and U(VI) adsorption onto palygorskite

Cited by 66 publications

References 55 publications

Mercury Removal from Aqueous Solutions Using Modified Pyrite: A Column Experiment

Mercury Removal from Aqueous Solutions Using Modified Pyrite: A Column Experiment

Adsorption Behavior of Acid-Treated Brazilian Palygorskite for Cationic and Anionic Dyes Removal from the Water

Green Preparation of Nanoporous Pyrrhotite by Thermal Treatment of Pyrite as an Effective Hg(Ⅱ) Adsorbent: Performance and Mechanism

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