Suspension impregnation method

Early work on the use of foams and mats has been reviewed [9j. Nickel fiber, nickel-plated steel fiber, or nickel-plated graphite fiber mats are preferred because they have smaller pores ( 50(im) [14]. The most recently developed mats can have porosities as high as 95% [13] and are much lighter than the sintered nickel plaques, which typically have porosities between 80 and 90%. Initially, standard cathodic impregnation methods were used to load the active material into the foam [9]. More recently, the preferred method is to incorporate the Ni(OH)2 in the form of a slurry into the mat [13, 14]. This has been called the suspension impregnation method [14]. Considerable improvement in the Ni(OH)2 has been achieved by the addition of divalent Co compounds to the slurry. The best results... 

Infiltration of a sufficient amount of metal precursors in the mesopores is necessary. The simplest way is to mix mesoporous silica in an ethanol solution of metal salts and then to evaporate the ethanol. The precursor molecules might enter the pores during the evaporation of ethanol by capillary action. The two solvent impregnation method, in which a suspension of mesoporous silica in dry hexane is mixed with an aqueous solution of metal nitrate and then dried, was applied to complete the infiltration. Modification of the mesopore surface to accelerate infiltration was reported. If the melting point of the metal precursor... 

Reduction is the most common technique to prepare polymer-immobilized nanoparticles. Two different types of reduction can be considered. The first type, or the impregnation method, consists of the chemical reduction of metals from solutions or suspensions of their salts. Ammoniacal solutions of Cu, Cr, and Ag hydroxides are often used. Electrochemical or radiation-induced reduction in the presence of macroligands have also been employed. The reduction of mononuclear metal complexes chemically bound with polymers represent the second type. The impregnation method is more widely applied because it better meets the needs of catalysis. In particular, metal blacks, ultradispersed powders, etc. are prepared. For example, Raney nickel is stabilized by incorporating it into the silicone rubber "" followed by vulcanization at room temperature. 

Carelli, V., Di Colo, G., Nannipieri, E., and Serafim, M.F., 1989, Evaluation of solution impregnation method for loading drugs into suspension-type polymer matrices A study of factors determining the patterns of solid drug distribution in matrix and dmg release from matrix, Int. J. Pharm. 55 199-207. 

Phosphate must be applied as fertilizer to the soil. Ideally it is added in quantities sufficient to guarantee optimal yields, but not in excess in order to avoid P transportation into other compartments of the ecosystem. The amount added should be based on an accurate estimation of the plant-available fraction of P already present in a soil.This is an old and difficult task and a large number of extraction methods have been used since intensive land use was practised. Recently methods have been worked out in which a strip of filter paper impregnated with an Fe oxide (2-line ferri-hydrite) is dipped into a soil suspension and the amount of P adsorbed by the paper is taken as being plant-available (Sissingh,1988 Van der Zee et ah, 1987 Sharpley, 1993 Sharpley et ah,1994 Kuo and Jellum, 1994 Myers et ah 1997). Anion and cation resins extracted more P from four heavily fertilized soils than from goethite (Delgado Torrent, 2000). Other oxyanions adsorbed by soil Fe oxides are silicate, arsenate, chromate, selenite ( ) and sulphate. Adsorption of sulphate led to a release of OH ions and was substantially lowered once the Fe oxides were selectively removed (Fig.16.17). 

The material is impregnated with the vat-acid suspension and subsequently converted into the substantive soluble form by treatment with sodium hydroxide. The usual methods of oxidation and soap boiling are employed. The advantage of using acid leuco compounds is that their suspensions are much finer than those of pigments, therefore giving better... 

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