Environmental Reactions of Air-Quality Protection on Eco-Friendly Iron-Based Catalysts

Abstract

A series of iron functionalized hydroxyapatite (Fe/HAP) samples with different metal loading (2 < wt.% Fe < 13) was prepared by a flash ionic exchange procedure from iron(III) nitrate as precursor and tested in some environmental air-quality protection reactions such as the catalytic reduction of NOx by NH3 (NH3-SCR), catalytic oxidation of NH3 (NH3-SCO) and catalytic N2O decomposition. The catalytic performances of the Fe/HAP catalysts were determined under flow conditions as a function of temperature and using reactant concentrations typical of polluting gaseous emissions from industrial vents. Physico-chemical characterization with various techniques of study (UV-DR and Mössbauer spectroscopies, NH3 titration, N2-physisorption, and XRPD analyses) provided valuable information on Fe-speciation, acidity, morphology, and structure of the samples. In general, highly dispersed Fe3+ centers were the predominant species, irrespective of Fe-loading, while just low percentage (≤15%) of FexOy nanoclusters (2 < size/nm < 4) was detected on the samples. As expected, the differences in iron concentration produced a diversified effect of both catalyst properties and catalytic activity, comprising the conversion and selectivity profiles, different for each reaction considered. The obtained results indicate a good potentiality for the eco-friendly Fe-catalysts for some environmental reactions of air protection.

Efficient Day-and-Night NO2 Abatement by Polyaniline/TiO2 Nanocomposites

“…In this drastic scenario, over the years numerous strategies have been developed and properly optimized with the final aim of decomposing NOx species. Among all the possibilities, their selective catalytic reduction by ammonia as a reducing agent (NH 3 -SCR) is one of the most studied and applied technologies [ 7 , 8 , 9 ], as well as absorption and adsorption routes [ 6 , 10 ]. However, from a practical viewpoint all these techniques suffer from several drawbacks, limiting their real application [ 3 , 8 , 11 ].…”

Effect of Co Doping on Magnetic and CO-SCR Properties of γ-Fe2O3

“…The results show that the core size and loading of Fe were controlled by adjusting synthesis parameters, while the packaging process of the multilayer material was irrelevant to the properties of iron oxide in the nucleus . Meanwhile, the magnetic core-shell structure materials as a magnetic separable carrier can be utilized in the field of water purification and the like by composite or modification with other materials. , …”

“…25 Meanwhile, the magnetic core-shell structure materials as a magnetic separable carrier can be utilized in the field of water purification and the like by composite or modification with other materials. 26,27 Fe 2 O 3 has the most stable phase among all iron oxides, in which γ-Fe 2 O 3 is a magnetic substance with a cubic or tetragonal structure. It has become the subject and interest of modern material research due to its unique and fascinating magnetic, electrical, and dielectric properties.…”

Incorporation of Iron(II) and (III) in Hydroxyapatite—A Theoretical Study

“…[20], thereby making exchanged HAp efficient catalytic systems. Accordingly, the synthesis and study of HAp-based catalytic systems with iron impurities have attracted great interest in recent years [21][22][23][24][25][26]. As reviewed by Goldberg et al [27,28], Fe-HAp and Fe oxide nanoparticles demonstrated high efficiency as a catalyst in the field of heavy oil purification via oxidative desulfurization and aquathermolysis methods, oil asphaltene extraction, etc.…”

“…[20], thereby making exchanged HAp efficient catalytic systems. Accordingly, the synthesis and study of HAp-based catalytic systems with iron impurities have attracted great interest in recent years [21][22][23][24][25][26].…”