Different crystal-forms of one-dimensional MnO2 nanomaterials for the catalytic oxidation and adsorption of elemental mercury

Xu, Haomiao; Zhao, Songjian; Mei, Jian; Quan, Fuquan

doi:10.1016/j.jhazmat.2015.06.012

Cited by 116 publications

(35 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The peak at 305 °C was the strongest, which could be attributed to the reduction of Mn 4+ to Mn 3+ . In addition, the peak at 405 °C could correspond to the reduction of Mn 3+ to Mn 2+ Xu et al 2015). This agrees with the results from XPS showing that only Mn 4+ and Mn 3+ existed, whether the catalyst was used or not, as the test temperature was only 200 °C, which was much lower than the reduction temperature of Mn 3+ to Mn 2+ .…”

Section: Effect Of Hgsupporting

confidence: 88%

Simultaneous oxidation of Hg0 and NH3-SCR of NO by nanophase Ce x Zr y Mn z O2 at low temperature: the interaction and mechanism

Zeng

et al. 2018

Environ Sci Pollut Res

View full text Add to dashboard Cite

Simultaneous oxidation of Hg and NH-SCR of NO by catalyst is one of the key methods for co-purification of coal-fired flue gas. Till now, the interaction between the oxidation of Hg and NH-SCR of NO and its mechanism have not clarified. In this study, a series of nanophase Ce Zr Mn O was prepared for the simultaneous oxidation of Hg and NH-SCR of NO at low temperature. The catalysts were characterized using surface area analysis, X-ray diffraction, temperature-programmed techniques, and several types of microscopy and spectroscopy. The experimental results indicated that the CeZrMnO exhibited superior Hg removal efficiency (> 99%) and NO conversion efficiency (> 90%) even at 150 °C, and it also exhibited a good durability in the presence of SO and HO. The excellent performance of CeZrMnO on co-purifying Hg and NO was due to the stronger synergistic effects of Ce-Zr-Mn in CeZrMnO than that of the others, which was illustrated by the characterization results of XPS, XRD, and FT-IR. Moreover, it was found that the NO conversion of CeZrMnO could be slightly influenced by Hg and was decreased about 4% to the max, while that of Hg could rarely be affected by the selected catalytic reduction process of NO. It might be due to the co-purification mechanism of NO and Hg. The mechanism of the simultaneous oxidation of Hg and NH-SCR of NO was mainly due to the synergetic effect on the mobility of surface oxygen and the activation of lattice oxygen of CeZrMnO. The effect of the oxidation of Hg on the NH-SCR of NO was mainly due to the absorbed Hg/Hg on the surface of CeZrMnO, which attenuated the formation of NH, -NH, and NH on its acid sites. Similarly, the NH-SCR of NO process could hardly influence the oxidation of Hg when NO and Hg were co-purified.

show abstract

Section: Effect Of Hgsupporting

confidence: 88%

Simultaneous oxidation of Hg0 and NH3-SCR of NO by nanophase Ce x Zr y Mn z O2 at low temperature: the interaction and mechanism

Zeng

et al. 2018

Environ Sci Pollut Res

View full text Add to dashboard Cite

show abstract

“…As for a-, b-, gand l-MnO 2 , N 2 molecules were mainly adsorbed on the external surface. 23 The XPS spectra of the adsorbents in the Mn 2p 3/2 and O 1s regions are compared in Fig. 3a and b, respectively.…”

Section: Characterization Of Adsorbentsmentioning

confidence: 99%

“…21 The inuence of crystal forms on MnO 2 catalytic performance has been extensively studied. 22,23 Different crystallographic MnO 2 materials were also prepared for pollutants adsorption, and MnO 2 adsorbents showed varying adsorption performance depending on the surface area and crystalline structure. Zhang et al investigated the effect of the crystallographic structure of MnO 2 on Li + adsorption, and found that MnO 2 ion sieve with l-crystallographic structure exhibited higher capacity for Li(I) selective adsorption.…”

Section: Introductionmentioning

confidence: 99%

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

Zhang

et al. 2017

RSC Adv.

View full text Add to dashboard Cite

show abstract

“…Furthermore, it has been reported that the shape and crystallographic phases of Mn based sorbents have serious effects on Hg 0 removal performance. Xu et al [20] synthesized three different crystallographic phases of MnO 2 and found that α-MnO 2 had the highest capacity due to its larger surface area and oxidizability. Chalkidis et al [21] pointed out that MnO 2 nano-rods possessed good Hg 0 removal capacity owing to the higher surface adsorbed oxygen species.…”

Section: Introductionmentioning

confidence: 99%

Promoting Effect of the Core-Shell Structure of MnO2@TiO2 Nanorods on SO2 Resistance in Hg0 Removal Process

Zhang

Han

et al. 2020

Catalysts

View full text Add to dashboard Cite

Sorbent of αMnO2 nanorods coating TiO2 shell (denoted as αMnO2-NR@TiO2) was prepared to investigate the elemental mercury (Hg0) removal performance in the presence of SO2. Due the core-shell structure, αMnO2-NR@TiO2 has a better SO2 resistance when compared to αMnO2 nanorods (denoted as αMnO2-NR). Kinetic studies have shown that both the sorption rates of αMnO2-NR and αMnO2-NR@TiO2, which can be described by pseudo second-order models and SO2 treatment, did not change the kinetic models for both the two catalysts. In contrast, X-ray photoelectron spectroscopy (XPS) results showed that, after reaction in the presence of SO2, S concentration on αMnO2-NR@TiO2 surface is lower than on αMnO2-NR surface, which demonstrated that TiO2 shell could effectively inhibit the SO2 diffusion onto MnO2 surface. Thermogravimetry-differential thermosgravimetry (TG-DTG) results further pointed that SO2 mainly react with TiO2 forming Ti(SO4)O in αMnO2-NR@TiO2, which will protect Mn from being deactivated by SO2. These results were the reason for the better SO2 resistance of αMnO2-NR@TiO2.

show abstract

Different crystal-forms of one-dimensional MnO2 nanomaterials for the catalytic oxidation and adsorption of elemental mercury

Cited by 116 publications

References 30 publications

Simultaneous oxidation of Hg0 and NH3-SCR of NO by nanophase Ce x Zr y Mn z O2 at low temperature: the interaction and mechanism

Simultaneous oxidation of Hg0 and NH3-SCR of NO by nanophase Ce x Zr y Mn z O2 at low temperature: the interaction and mechanism

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

Promoting Effect of the Core-Shell Structure of MnO2@TiO2 Nanorods on SO2 Resistance in Hg0 Removal Process

Contact Info

Product

Resources

About