The Characterization and SCR Performance of Mn-Containing α-Fe2O3 Derived from the Decomposition of Siderite

Abstract

In this work, a nano-structured iron-manganese oxide composite was prepared by calcining natural manganese-rich siderite at different temperatures (450, 500, 550, 600 °C, labeled as H450, H500, H550, H600, respectively), and their performances of selective catalytic reduction (SCR) of NO by NH3 were investigated. XRD, XRF, BET, XPS, SEM, and TEM were used to investigate the morphology, composition, and surface characteristics of the catalyst. The results showed that the decomposition of siderite occurred from 450 °C to around 550 °C during the calcination in air atmosphere; moreover, the siderite could be converted into nano-structured α-Fe2O3. The specific surface area of the material increased, and Mn2+ was transformed into Mn4+, which were beneficial to the SCR. Among these catalysts, H550 had the best SCR performance, with NO removal of 98% at a temperature window from 200 to 250 °C. The presence of water vapor and sulfur dioxide can inhibit the SCR performance of the catalysts, but this inhibition effect was not obvious for H550 at the optimum reaction temperature (250 °C). The findings presented in this study are significant toward the application of the Mn-rich siderite as a precursor in preparing the Fe-Mn oxides for catalytic de-NOx by SCR.

An Investigation into the Adsorption of Ammonium by Zeolite-Magnetite Composites

“…The adsorption curves of both N-Zeo and M-Zeo showed a shape of IV isotherm (Figure 3), implying the characteristic feature of mesoporous materials. Thus, these mesoporous materials provide more internal specific surface and pore volume [34]. The BET-specific surface area, pore volume, and pore size are templated in Table 1.…”

Activation of peroxydisulfate by thermally‐treated natural siderite to degrade sulfamethazine: performance and mechanism

“…Siderite (FeCO 3 , a carbonate mineral abundant worldwide) and its thermally‐treated products (e.g., Fe 2 O 3 and Fe 3 O 4 , which depend on calcination atmosphere and temperature) are utilized in various fields of environmental remediation 12,17‐19 . To our best knowledge, few studies on the use of Fe 3 O 4 obtained by thermally‐treated natural siderite to activate PDS have been reported.…”

“…Siderite (FeCO 3 , a carbonate mineral abundant worldwide) and its thermally-treated products (e.g., Fe 2 O 3 and Fe 3 O 4 , which depend on calcination atmosphere and temperature) are utilized in various fields of environmental remediation. 12,[17][18][19] To our best knowledge, few studies on the use of Fe 3 O 4 obtained by thermally-treated natural siderite to activate PDS have been reported. Therefore, the purposes of this work are: (i) to investigate the performance of thermally-treated siderite on the degradation of organic pollutants via PDS activation; (ii) to consider the reaction mechanism and the influence of parameters on PDS activation; and (iii) to propose a potential pathway for SMT degradation in a magnetite/PDS system and predict the toxicity of intermediates.…”