Mixed cobalt–iron oxide absorbents for low-temperature gas desulfurisation

Mesoporous-molecular-sieve-supported Polymer Sorbents for Removing H2S from Hydrogen Gas Streams

“…At 22°C, the breakthrough capacity and saturation capacity of PEI(50)/SBA-15 were 0.79 and 1.98 mmol-H 2 S/g-sorb, respectively, which were about 20 times as large as those at 75°C (0.037 and 0.11 mmol-H 2 S/g-sorb, respectively). This saturation capacity is significantly higher than that reported in literature for the amine-grafted MCM-48 adsorbent [31] and is in the same magnitude as those reported for the mixed metal oxides [13,[15][16][17][18][19][20] at the comparable sorption temperature. In our previous study, it was also found that for the sorption of CO 2 on a PEI/MCM-41 sorbent, the sorption capacity increased with increasing temperatures from 50 to 75°C and then, decreased with continuous increase in temperatures [26].…”

“…In the range of 25-100°C, Carnes and Klabunde [13] found the activity of nanocrystalline metal oxides prepared by a sol-gel method decreased in the order of ZnO [ CaO [ Al 2 O 3 [ MgO. In order to improve the adsorption capacity at low temperature, many metal oxides have been tested and investigated, which includes ferric oxyhydroxides (FeOOH) [14], iron, copper, and cobalt doped zinc oxide [15], cobalt-zinc-aluminum oxides [16], iron-zinc and iron-cobalt mixed oxides [17,18], and Zn-Ti-based oxides [19,20]. However, the regeneration of the spent metal-oxide-based sorbents needs to be conducted usually at high temperature ([450°C) in the presence of O 2 .…”

Structural and morphological transformations of Zn–Al layered double hydroxides through hydrothermal treatment

“…Within the layers, the cations are uniformly distributed on an atomic level without segregation of ''lakes'' of separate cations [7]. Accordingly, LDH are provided as a single-source precursor for the synthesis of transition metal oxides as they have a low decomposition temperature and ensure a homogeneous distribution of metal ions in the precursor [8][9][10]. Further, the decomposition is accompanied by a large mass, by virtue of which, the product oxide has a nanoparticulate morphology [11].…”

Solution decomposition of the layered double hydroxide of Co with Fe: Phase segregation of normal and inverse spinels

“…The unitary hydroxide of Co(II), Co(OH) 2 The thermal decomposition of the Co-Fe LDHs has been reported over a range of temperatures. At lower temperatures (<450 • C) a single-phase Fe-substituted Co-rich spinel [4,6] is observed. The Fe-Co-O phase diagram [10,11] shows that for Co/(Co + Fe) ratios corresponding to that found in LDHs (0.66-0.80), complete solubility of Co and Fe spinels is attained only above ∼900 • C. At lower temperatures (<900 • C), a solubility gap is seen in the phase diagram comprising cobaltite and ferrite.…”

“…Further, the decomposition is accompanied by a large mass loss, by virtue of which, the product oxide has a nanoparticulate morphology [1]. There is an added significance, in the case of Co(II)-based LDHs, as the product of decomposition is a spinel [1,[3][4][5][6]. Spinels of Co 2+ (general formula, CoB 2 O 4 ) are technologically important as magnetic storage materials and catalysts [7][8][9].…”