Iron–calcium–hydroxyapatite catalysts: Iron speciation and comparative performances in butan-2-ol conversion and propane oxidative dehydrogenation

Khachani, Mariam; Kacimi, M. El; Ensuque, Alain; Piquemal, Jean‐Yves; Connan, Carole; Bozon‐Verduraz, François; Ziyad, Mahfoud

doi:10.1016/j.apcata.2010.08.043

Cited by 57 publications

(38 citation statements)

References 58 publications

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“…The P/Ca ratio for nAp is somewhat higher than the expected theoretical Ca(PO 4 ) 0.6 O 0.2 stoichiometric ratio but close to the values reported in the literature for several hydroxyapatite materials and attributed to the presence of surface acid phosphates. 29 On the other hand, the O/P ratio is, within the experimental error, in line with the expected value for hydroxyapatite. Fe-nAp shows higher P/Ca and O/Ca ratios than nAp.…”

Section: Particle Characterizationsupporting

confidence: 82%

Paramagnetic Iron-Doped Hydroxyapatite Nanoparticles with Improved Metal Sorption Properties. A Bioorganic Substrates-Mediated Synthesis

Mercado

Magnacca

Malandrino

et al. 2014

ACS Appl. Mater. Interfaces

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This paper describes the synthesis of paramegnetic iron-containing hydroxyapatite nanoparticles and their increased Cu 2+ sorbent capacity when using Ca 2+ complexes of soluble bio-organic substrates from urban wastes as synthesis precursors. A thorough characterization of the particles by TEM, XRD, FTIR spectroscopy, specific surface area, TGA, XPS, and DLS, indicates that loss of crystallinity, a higher specific area, an increased surface oxygen content, and formation of surface iron phases strongly enhance Cu 2+ adsorption capacity of hydroxyapatite-based materials. However, the major effect of the surface and morphologycal modifications is the size diminution of the aggregates formed in aqueous solutions leading to an increased effective surface available for Cu 2+ adsorption. Maximum sorption values of 550 -850 mg Cu 2+ per gram of particles suspended in an aqueous solution at pH 7 were determined; almost 10 times the maximum values observed for hydroxyapatite nanoparticles suspensions under the same conditions.

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Section: Particle Characterizationsupporting

confidence: 82%

Paramagnetic Iron-Doped Hydroxyapatite Nanoparticles with Improved Metal Sorption Properties. A Bioorganic Substrates-Mediated Synthesis

Mercado

Magnacca

Malandrino

et al. 2014

ACS Appl. Mater. Interfaces

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“…The strength of the acidity, the highest selectivity towards products and the turnover numbers are in the order: Sr-HAp > Mg-HAp > Ca-HAp > Ba-HAp. 4 Product selectivity in the activation of n-octane over alkaline-earth metal hydroxyapatite catalysts at an iso-conversion of 8 % (GHSV = 3700-4250 h -1 , n-octane to oxygen molar ratio of 1:1, temperature = 500 °C). …”

Section: Resultsmentioning

confidence: 99%

“…3 It was also shown that the catalytic performance in these reactions depends on the acidbase properties of the catalyst, in addition to isolated cations capable of activating C-H bonds and sites that can activate the oxygen. 4 Hydroxyapatite (HAp) has acid-base character, offers high stability, allows substitution into the apatite structure and the phosphate groups present in the structure are capable of activating oxygen. 5 Hydroxyapatite has the general formula, [Ca10-x(HPO4)x(PO4)6-x(OH)2-x, 0 £ x £ 1].…”

Section: Introductionmentioning

confidence: 99%

A kinetic insight into the activation of n-octane with alkaline-earth metal hydroxyapatites

2015

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Alkaline-earth metal hydroxyapatites are prepared by the co-precipitation method and characterized using XRD, ICP, NH 3 -TPD, SEM-EDX, TEM and N 2 physisorption analysis. The metal present in the hydroxyapatite influences the acidity of the catalyst. Oxidative dehydrogenation reactions carried out in a continuous flow fixed bed reactor showed that the selectivity towards desired products was dependent on the alkaline-earth metal in the hydroxyapatite. All hydroxyapatite catalysts showed high selectivity towards carbon oxides, followed by cracked products, octenes and aromatics. The highest selectivity and turnover numbers towards C8 products and a high specific rate was shown by Sr-HAp. The activation of n-octane over these catalysts followed the Eley-Rideal mechanism.

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“…For example, calcium hydroxyapatite containing transition metals were found to be very active in the methane dry reforming [2], the hydrogenolyse of S-containing substrates [3], the propane oxidative dehydrogenation [4] and the epoxidation of olefin [5] Within our research team, we have been looking for some new catalytic applications for apatitic compounds with a special interest for hydroxyapatite. Most of these studies are focused on the hydrodesulfurization (HDS) of petroleum distillate fractions for the reduction of atmospheric pollution due to the emission of hazardous compounds such as SO 2 .…”

Section: Introductionmentioning

confidence: 99%

Preparation, characterization of Mo catalysts supported on Ni- containing calcium deficient hydroxyapatite and reactivity for the thiophene HDS reaction

Cherif

Hadhoudi

Ezzamouri

et al. 2013

MATEC Web of Conferences

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Abstract. Ni-containing Calcium Hydroxyapatite (NiCaHAp; 3.31 wt.% Ni) was synthesized by coprecipitation and used as catalyst support. Molybdenum was supported on NiCaHAp by impregnation using ammonium heptamolybdate. The prepared catalysts Mo(x)/NiCaHAp (x: 2 to 8 wt % in Mo) were characterized by elemental analysis, XRD, FT-IR, N 2 adsorptiondesorption and TEM-EDX. The catalysts were sulfided in-situ at 673 K under flowing H 2 S/H 2 (15 Vol.% H 2 S) and tested in hydrodesulfurization (HDS) of thiophene at 673 K. The main XRD peaks of hydroxyapatite CaHAp phase were observed in all samples and a peak due probably to crystalline MoO 3 phase was also identified from the results. However, no crystalline phase of NiO was found for the catalysts, which showed its Ni species were highly dispersed. The sulfided catalysts Mo(x)/NiCaHAp presented are active in HDS of thiophene, despite the presence of some large MoO 3 crystallites and incomplete sulfidation. This activity may be due to interaction of NiO and MoO 3 on CaHAp resulting in the formation of Ni-Mo-S phase under flowing H 2 S/H 2 . When the molybdenum content increased the HDS activity increasead slightly, which was caused by the agglomeration of MoO 3 . The Mo(8)/NiCaHAp catalyst is about two times less active for thiophene HDS than the commercial NiMoP/Al 2 O 3 .

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Iron–calcium–hydroxyapatite catalysts: Iron speciation and comparative performances in butan-2-ol conversion and propane oxidative dehydrogenation

Cited by 57 publications

References 58 publications

Paramagnetic Iron-Doped Hydroxyapatite Nanoparticles with Improved Metal Sorption Properties. A Bioorganic Substrates-Mediated Synthesis

Paramagnetic Iron-Doped Hydroxyapatite Nanoparticles with Improved Metal Sorption Properties. A Bioorganic Substrates-Mediated Synthesis

A kinetic insight into the activation of n-octane with alkaline-earth metal hydroxyapatites

Preparation, characterization of Mo catalysts supported on Ni- containing calcium deficient hydroxyapatite and reactivity for the thiophene HDS reaction

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