Effects of Mn(II) addition on Cd(II) removal by hydrated manganese dioxide

Birnessite-Type MnO2 Modified Sustainable Biomass Fiber toward Adsorption Removal Heavy Metal Ion from Actual River Aquatic Environment

“…The peaks at 2915 and 2853 cm –1 were corresponding to the asymmetric and symmetric stretching vibrations of C–H . The peaks around 1640 and 1556 cm –1 might be attributed to the bending vibrations of Mn–OH group and asymmetrical deformation vibrations of COO-, respectively. , An obvious change in the spectrum for MnO 2 @CHF, characteristic peak at 510 cm –1 could be assigned to the stretching vibration peaks of Mn–O, which might be one of main complexation sites for heavy metals. , The above results suggested that hydrothermal modification of KMnO 4 promoted the enrichment of oxygen-containing functional groups of MnO 2 @CHF, and they also confirmed the deposition of MnO 2 .…”

“…Consequently, the shift of the binding energy of Mn 2p and the appearance of Mn (II) and Mn (III), the ion exchange and redox reaction were involved in Cd (II) adsorption on MnO 2 @CHF. 41,54 Similarly, two characteristic peaks of the O 1s in original MnO 2 @CHF were observed at 532.03 and 529.89 eV, corresponding to C−OH/−COOH and Mn−O, respectively (Figure 9c). The O 1s spectrum of the adsorbed MnO 2 @CHF after Cd (II) adsorption could be divided into three peaks, located at 532.98 eV (hydration oxygen, H−O−H), 532.18 eV (hydroxyl oxygen, C−OH/-COOH), and 529.88 eV (lattice oxygen bonded to metal, Mn−O/Cd-O).…”

“…39,40 An obvious change in the spectrum for MnO 2 @CHF, characteristic peak at 510 cm −1 could be assigned to the stretching vibration peaks of Mn−O, which might be one of main complexation sites for heavy metals. 25,41 The above results suggested that hydrothermal modification of KMnO 4 promoted the enrichment of oxygen-containing functional groups of MnO 2 @CHF, and they also confirmed the deposition of MnO 2 .…”

“…Meanwhile, the valence states of the Mn element after adsorption included Mn (IV), Mn (II) and Mn (III), as shown in the inset of Figure b. Consequently, the shift of the binding energy of Mn 2p and the appearance of Mn (II) and Mn (III), the ion exchange and redox reaction were involved in Cd (II) adsorption on MnO 2 @CHF. , …”

“…The changes in the intensities and binding energy of Mn 2p and O 1s indicated that MnO 2 and functional oxygen-containing groups had certain contributions to the adsorption with the action of surface complexation, ion exchange, redox, etc. Finally, two distinct absorption peaks at binding energies of 405.33 and 412.03 eV, allocated to Cd 3d5/2 and Cd 3d3/2, were observed in the adsorbed MnO 2 @CHF after Cd (II) adsorption (Figure 9d), 41 proving that Cd (II) had been successfully adsorbed on the MnO 2 @CHF surface.…”