The Preparation and Pretreatment of Coprecipitated Nickel-Alumina Catalysts for Methanation at High Temperatures

Kruissink, E.C.; Doesburg, E.B.M.; Reijen, L. L. van; Alzamora, Luis; Orr, Sophie; Ross, J.R.H.; Veen, Gijs van der

doi:10.1016/s0167-2991(09)60210-x

Cited by 17 publications

(7 citation statements)

References 5 publications

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“…the 003 spacings are always smaller than for the corresponding sulphate forms, in agreement with our observations. The differences observed in layer thickness probably correspond to different orienta-fions of nitrate in the interlayer (Kruissink et al, 1981). Thus the small 003 spacing of the nitrateinterlayered GR (Fig.…”

Section: The Structural Chemistry Of Nitrate Reductionmentioning

confidence: 93%

Reduction of nitrate to ammonium by sulphate green rust: activation energy and reaction mechanism

Hansen¹,

Koch²

1998

Clay miner.

123

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Iron(II)-containing minerals are potential inorganic nitrate reductants in soils and sediments. Specifically, synthetic green rust (Fe4IIFeIII2(OH)12SO4.yH2O, GR) reduces nitrate to ammonium. The reaction of GR with two different nitrate salts, NaNO3 and Ba(NO3)2, has been compared. The reaction stoichiometry and the reaction order with respect to Fe(II) in GR does not change in the examined temperature range (15-50°C) irrespective of the nitrate salt used. Activation energies of 83.9±7.6 kJ mol-1 and 90.5±6.9 kJ mol-1 have been determined for the reaction of GR with NaNO3 and Ba(NO3)2, respectively. However, for the latter reaction the rate of reaction is increased 40 times. Based on X-ray and M6ssbauer investigations, this acceleration of the reaction rates is attributed to the forced exchange of sulphate with nitrate in GR interlayers caused by precipitation of BaSO4 outside the GR particles, a reaction which does not occur in the presence of NaNO3. This difference in anion exchange behaviour is confirmed by anion exchange experiments with the redox-inactive GR-analogue, pyroaurite. A reaction model initiated by nitrate electrostatically bound at positively charged sites of GR is proposed.

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Section: The Structural Chemistry Of Nitrate Reductionmentioning

confidence: 93%

Reduction of nitrate to ammonium by sulphate green rust: activation energy and reaction mechanism

Hansen¹,

Koch²

1998

Clay miner.

123

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“…Preparation methods affect the dispersion of active metal 68 and metal-support interactions, 196 which in turn further inuences the catalytic performance. 197 Traditional methods including impregnation, 28,30,40,41,45,170,171,193,198,199 precipitation, 43,95,109,157,200 and sol-gel methods 31,63,110,201 have been widely applied in methanation catalysts synthesis. Some other methods such as deposition-precipitation, 46,142 hydrothermal synthesis, 38,202 ion exchange method, 203 mechanical mixing, 204 solution combustion method, 96 and microwave heating 77 were also used in preparing methanation catalysts.…”

Section: Preparation Methodsmentioning

confidence: 99%

Recent advances in methanation catalysts for the production of synthetic natural gas

et al. 2015

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“…As it has been suggested earlier, this phenomenon can be attributed to Na ? ion adsorption on the aluminum hydroxide/oxyhydroxide compounds during synthesis of the samples [57].…”

Section: Chemical Analysismentioning

confidence: 99%

“…In a series of articles [57][58][59][60][61] Kruissink et al have claimed that a thermal treatment of co-precipitated Ni-Al precursors of Ni 2? /Al 3?…”

Section: Introductionmentioning

confidence: 99%

Ni–Al layered double hydroxides as catalyst precursors for CO2 removal by methanation

Gabrovska

Edreva-Kardjieva

Crışan

et al. 2011

Reac Kinet Mech Cat

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The effect of nickel content on the structure and activity of co-precipitated Ni-Al layered double hydroxides (LDHs) as catalyst precursors for CO 2 removal by methanation was studied by variation of the Ni 2? /Al 3? molar ratio (Ni 2? /Al 3? = 3.0, 1.5 and 0.5), and of the reduction and reaction temperatures as well as of the space velocities. Powder X-ray diffraction (PXRD), H 2 chemisorption, and temperature programmed reduction (TPR) techniques were applied for physicochemical characterization of the samples. It was specified that the nanoscaled dimensions of the as-synthesized samples also generate nano-metrical metallic nickel particles (PXRD). The existence of readily and hardly reducible Ni 2? -O species in the studied samples (TPR), affects catalytic performance. The studied catalysts hydrogenate CO 2 effectively to residual concentrations of the latter in the range of 0-10 ppm at reaction temperatures from 400 to 220°C and space velocities between 22,000 and 3000 h -1 . The variation of the CO 2 methanation activity with the changes of space velocities depends on the nickel content, and reduction and reaction temperatures. After reduction at 400 and 450°C, a sample of Ni 2? /Al 3? = 3.0 has demonstrated the highest conversion degree at all the reaction temperatures and space velocities, while a catalyst of Ni 2? /Al 3? = 0.5 dominated in the methanation activity after reduction within 530-600°C. The Ni 2? /Al 3? = 1.5

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The Preparation and Pretreatment of Coprecipitated Nickel-Alumina Catalysts for Methanation at High Temperatures

Cited by 17 publications

References 5 publications

Reduction of nitrate to ammonium by sulphate green rust: activation energy and reaction mechanism

Reduction of nitrate to ammonium by sulphate green rust: activation energy and reaction mechanism

Recent advances in methanation catalysts for the production of synthetic natural gas

Ni–Al layered double hydroxides as catalyst precursors for CO2 removal by methanation

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