Pore-volume impregnation

In the result of the sequential impregnation pore volume of precursor was diminished almost twice and surface area by 30 %. However in this series of experiments hydrothermal treatment gave results quite reverse result. In this case small increase in pore volume and specific surface area was observed while increase in average pore radius size was negligible. 

Eor the negative electrolyte, cadmium nitrate solution (density 1.8 g/mL) is used in the procedure described above. Because a small (3 —4 g/L) amount of free nitric acid is desirable in the impregnation solution, the addition of a corrosion inhibitor prevents excessive contamination of the solution with nickel from the sintered mass (see Corrosion and corrosion inhibitorsCorrosion and corrosion control). In most appHcations for sintered nickel electrodes the optimum positive electrode performance is achieved when one-third to one-half of the pore volume is filled with active material. The negative electrode optimum has one-half of its pore volume filled with active material. 

In both cases, we observe an amorphous pattern no crystallites of rare earth oxide appear even at 25% wt. loading. This indicates that oxide particles remain less than 30A in diameter. The surface area, pore volume and pore size distribution of the starting Si-Al support also change on impregnation. Table 1 lists the values for yttria-modified samples of... 

Impregnation. Two methods are used in adding the active phase dry and wet impregnation. Dry impregnation is also referred to as pore volume impregnation , because... 

Reaction conditions aUcenerCOrEL = 1 1 1, T = 100 °C, 0.2 wt% Rh metal loading, silica 100 p = 10 bar for guanidinium and norbos-Cs, p = 5 bar for sulfoxantphos ionic liquid used for impregnation [BMIM][PF6] a) molar ligand to metal ratio b) ratio of ionic liquid volume to support pore volume c) mol aldehyde per mol rhodium per hour d) ratio between linear and branched aldehyde e) support loaded with ionic liquid only. 

In the slurry impregnation method, which adheres in part to a patented procedure,35 the ratio of the volume of loading solution used to the weight of alumina was 1 1, such that approximately 2.5 times the pore volume of solution was used... 

Catalyst. A pure precipitated Si02 sample (grade Si 4-5P, AKZO product BET S.A., 395 m g" Pore Volume, 1.14 cm -g" ) has been used "as received", while 4% MoOj/SiOj (BET S.A., 187 m g-l) and 5% V205/Si02 (BET S.A., 231 m2.g-i) catalysts have been prepared by incipient wetness impregnation of the "Si4-5P" Si02 with a basic solution (pH=11) of ammonium heptamolybdate and ammonium metavanadate respectively (23). The impregnated samples were dried at 90°C for 24h and then calcined at 6C)0°C for 16h. 

Traditional powder metal bearings (Table 7) consist of bronze of 90% copper—10% tin. The common pore volume of 20—30% is usually impregnated with an oxidation-resistant oil of SAE 30 viscosity (22). High porosity with high oil content is favored for higher speed, light load applications. Lower porosity with up to 3.5% added graphite is desirable for low speeds and oscillation where oil-film formation is difficult. 

Aqueous ammonium heptamolybdate (Alfa, (NH4)6Mo70244H20, 99.999%) solutions were prepared so that a metal loading of 6 wt % Mo would fill 80% of the available pore volume of the mesoporous synthetic clays. Following Mo impregnation and recalcination at 400°C for 5 hr, the pore volumes were measured again using an established LN2 physisorption... 

The catalysts were prepared by impregnation of Si02 with an aqueous solution of H2PtCI6 and the appropriate promoting metal salts, using the incipient wetness technique. Si02, type M from Chemische Werke Uetikon, Switzerland, was used (20-35 mesh (ASTM), BET surface area 470 m2/g, pore volume 0,38 ml/g, composition 41,9% Si, 860 ppm Ca, 150 ppm Mg, <200 ppm Na, <200 ppm Al, <200 ppm Ti, <150 ppm Fe, 50 ppm S, 50 ppm Cl). The presence of Ca and... 

The method we applied is as follows The catalyst is sieved into a coarse and a fine fraction. The coarse fraction of the catalyst (PSD >75 yum) is impregnated homogeneously with about 4000 ppm vanadium fey a traditional pore volume impregnation method. 

The route of catalyst deactivation via a cyclic metal impregnation and deactivation method has produced significant improvements in approaching realistic vanadium and nickel profiles over the catalyst particles. From electron microprobe analyses of Ni and V loaded catalyst it has been established that after pore volume saturation, Ni and V are rather homogeneously distributed over the catalyst. 

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