Reaction of aqueous Cu–Citrate with MnO2 birnessite: Characterization of Mn dissolution, oxidation products and surface interactions

Jefferson, William A.; Hu, Chengzhi; Liu, Huijuan; Qu, Jiuhui

doi:10.1016/j.chemosphere.2014.04.039

Cited by 30 publications

(11 citation statements)

References 27 publications

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“…5a . As can be seen, it is found that the adsorption capacity of the adsorbent increased distinctly till a maximum value at pH 5.0, and then tended to be gentle above pH 5.0. pH could affect Cd(II) adsorption capacity in two ways, by influencing ion exchange and metal deposition reactions or by affecting the electric charge density of the surface to facilitate/hinder electrostatic interactions 53 . In terms of competition between H + and Cd 2+ and the protonation of the active sites of the adsorbent at a lower pH, the adsorption capacity was proved quite low at lower pH.…”

Section: Resultsmentioning

confidence: 99%

Creation of Hollow Calcite Single Crystals with CQDs: Synthesis, Characterization, and Fast and Efficient Decontamination of Cd(II)

Yang

Nie

et al. 2018

Sci Rep

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In this work, carbon quantum dots were first prepared through one-pot hydrothermal route of the propyl aldehyde and sodium hydroxide via an aldol condensation reaction, and a novel solid-phase extraction adsorbent of hollow calcite single crystals was prepared via the precipitation of metal nitrates by the CO2 diffusion method in the presence of CQDs and further applied for excessive Cd(II) ions removal from water. The spectra and morphologies of the etched calcite were investigated by X-ray diffraction, Fourier transform infrared spectrometry, Scanning electron microscope, and Transmission electron microscopy. The results show that the CQDs etching technique successfully furnish a strategy for manufacturing interface defects onto the calcite crystal. Bath studies were done to evaluate the effects of the major parameters onto Cd(II) adsorption by the etched calcite, such as pH, contact time, and initial Cd(II) concentration. The Cd(II) adsorption onto the new adsorbent could reach a maximum adsorption amount of 66.68 mg/g at 120 min due to the abundant exterior adsorption sites on the adsorbent. The adsorption kinetics and adsorption isotherms of Cd(II) on the etched calcite were also investigated. The experimental datum showed that the adsorption kinetics and isotherms of Cd(II) on the etched calcite were well-fitted by the pseudo-second-order kinetic model and the Freundlich isotherm model respectively. The adsorption mechanisms could be primarily explained as the formation of Cd(OH)2 and CaxCd1−xCO3 solid solution on the adsorbent surface with the help of X-ray photoelectron spectroscopy.

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Section: Resultsmentioning

confidence: 99%

Creation of Hollow Calcite Single Crystals with CQDs: Synthesis, Characterization, and Fast and Efficient Decontamination of Cd(II)

Yang

Nie

et al. 2018

Sci Rep

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“…3a, the Mn 2p 3/2 spectrums were asymmetrical and could be divided into three peaks at 639.9, 641.2 and 642.2 eV, assigned to Mn 2+ , Mn 3+ and Mn 4+ , respectively. 10,28 To obtain the relative quantity of Mn 2+ , Mn 3+ and Mn 4+ in the adsorbents, the Mn 2p 3/2 spectrums were tted according to the literature, 10,29 and the tting results are listed in Table 1. The content of Mn 3+ in aand b-MnO 2 were higher than others.…”

Section: Characterization Of Adsorbentsmentioning

confidence: 99%

Efficient removal of Pb(ii) ions using manganese oxides: the role of crystal structure

Zhang

et al. 2017

RSC Adv.

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“…5d), there were three peaks associated with different oxidation states of Mn. These peaks were located at binding energies of 640.6 eV, 641.6 eV, and 642.8 eV for Mn(II), Mn(III) and Mn(IV), respectively (Jefferson et al, 2015). According to the peak area analysis, Mn species in the solid phase were mainly present in Mn(III) and Mn(IV), indicating that most Mn(II) in the solid had been oxidized to Mn(III/IV) after the aging process.…”

Section: Xps Analysismentioning

confidence: 99%

Phase Transformation of Cr(VI)-Adsorbed Ferrihydrite at Different pH in The Presence of Mn(II): Fate of Mn(II) and Cr(VI)

Ding¹,

Fu²,

Sun³

et al. 2021

Preprint

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Ferrihydrite is an important sink for the toxic heavy metal ions, such as chromium(VI). As ferrihydrite is thermodynamically unstable and gradually transforms into hematite and goethite, the stability of Cr(VI)-adsorbed ferrihydrite is environmentally significant. This study investigated the phase transformation of Cr(VI)-adsorbed ferrihydrite at different pH in the presence of aqueous Mn(II), as well as the fate of Mn(II) and Cr(VI) in the transformation process of ferrihydrite. Among the ferrihydrite transformation products, hematite was dominant, and goethite was minor. The pre-adsorbed Cr(VI) inhibited the conversion of ferrihydrite to goethite at initial pH 3.0, whereas little amount of adsorbed Mn(II) favored the formation of goethite at initial pH 7.0. After the aging process, Cr species in solid phase existed primarily as Cr(III) in the presence of Mn(II) at initial pH 7.0 and 11.0. The aqueous Mn concentration was predominantly unchanged at initial pH 3.0, whereas the aqueous Mn(II) was adsorbed onto ferrihydrite or form Mn(OH)2 precipitates at initial pH 7.0 and 11.0, promoting the immobilization of Cr(VI). Moreover, the oxidation of Mn(II) occurred at initial pH 7.0 and 11.0, forming Mn(III/IV) (hydr)oxides.

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Reaction of aqueous Cu–Citrate with MnO2 birnessite: Characterization of Mn dissolution, oxidation products and surface interactions

Cited by 30 publications

References 27 publications

Creation of Hollow Calcite Single Crystals with CQDs: Synthesis, Characterization, and Fast and Efficient Decontamination of Cd(II)

Creation of Hollow Calcite Single Crystals with CQDs: Synthesis, Characterization, and Fast and Efficient Decontamination of Cd(II)

Efficient removal of Pb(ii) ions using manganese oxides: the role of crystal structure

Phase Transformation of Cr(VI)-Adsorbed Ferrihydrite at Different pH in The Presence of Mn(II): Fate of Mn(II) and Cr(VI)

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