Active clay

Clays, activated Clay treatment C1CH2CHC1CH20H C1CH2CHOHCH3 C1CH2CHOHCH2C1 1990 Clean Air Act Clean Air Act... 

Older rerefining units used 2-5 kg/L of activated clay at 40—70°C and higher temperatures in place of TEE to clean the oil (80). More elaborate chemical and hydrotreating of used engine oils without a distillation step has been developed by Phillips Petroleum for processing 40,000 /yr (10 X 10 gal/yr). Establishment of a reflable feedstock supply is a critical consideration for larger rerefining plants. 

Acid-cataly2ed isomerization of a-pinene is carried out by heating with catalysts or other activated clays. Camphene (13) and tricydene... 

Adsorbents. Acid activated clays have been widely used to treat mineral, vegetable, and animal oils. The primary objective of such treatment is decolorization and, at least in the case of edible oil, to remove components that contribute to off-tastes. Typically the oil is filtered through a granular clay product or treated with finely ground clay and subsequendy filtered. 

A wide range of clay materials have been used for decolorizing. These may be substantially cmde clay such as fuller s earth, which largely contains montmorillonite as the active clay ingredient, or specially treated attapulgites, montmorillonites, and kaolinites. Proprietary acid activation processes are frequentiy used for production of clay-derived materials of superior performance. 

Remarkably, seventy years after Houdry s utilization of the catalytic properties of activated clay and the subsequent development of ci ystalline aluminosilicate catalysts that arc a magnitude more catalytically active, the same fundamental principles remain the basis for the modern manufacture of gasoline, heating oils, and petrochemicals. 

Chemically active These filters are similar in design to the non-active depth units but the filtering media used are so chosen that contaminants adhere by chemical attraction. Thus there is a dual action, mechanical and chemical. The materials used include various activated clays. Fuller s earth, charcoal and chemically treated paper. Their cleansing action is much more thorough than that of the purely mechanical devices, for they are capable of removing matter actually in solution in the oil. 

Phosphoric acid esters having a low content of arsenic can be obtained by treating with 0.1-10% adsorbents such as activated clay, active carbon, alumina, and silica gel to decrease the arsenic content. Thus, 100 parts lauryl phosphate containing 10.3 ppm As and 2 parts activated clay were mixed at 60-70°C for 2 h and filtered to give lauryl phosphate only containing 0.6 ppm As [28]. 

Vaccari (1983,1999) has given a state-of-the-art account of the preparation and catalytic properties of cationic and anionic clays. Some examples of industrial importance have also been reported. Clays exhibit many desirable features, such as low cost, wide range of preparation variables, ease of set-up and wOrk-up, high selectivity, and environmental friendliness. Cationic clays are widespread in nature, whereas anionic clays are rarely found in nature, but they can be synthesized cheaply. Cationic clays are prepared from the minerals but industrial anionic clays are generally synthetic. Smectite clays exhibit both Brpnsted and Lewis acid sites on the edges of the crystals. Hammet s acidity function values are as follows Na -montmorillonite (M), -3 to t- 1.5 NH4VM -3 to 1.5 H M -8.2 to -5.6 acid activated clay less than -8.2. Laporte also has a synthetic version of cationic clays, Laponite. The acid... 

The pH and clay content of these soils are extremely important in understanding their chemistry. The lack of salts, low pH, and dominance of low activity clays will greatly affect the retention and extraction of components from both Ultisols and Spodosols. 

Surface area measurements of natiual and thermal activated clay minerals were made and the results are given Table 20.2. 

N natural clay sample TA thermal activated clay sample... 

When a reduced soil is re-oxidized, Fe " " changes into Fe(OH)3. The original Fe oxides are thus distributed differently, generally with a higher specific surface and activity. In high-activity clay soils, this may increase the stability of the structure established just before flooding. In low-activity clay soils the effects of alternate reduction and oxidation are less clearly beneficial, partly because of leaching of nutrients. 

The effect of NaCl concentration on the rate of paraquat adsorption on activated clays is reported by Tsai et al. (2003). The rate constant increases with an increase of salts in the aqueous paraquat solution from 0.046 (g mg min at a NaCl concentration of 0.05 M, to 0.059 (g mg" min" at a solution concentration of 2.50 M NaCl. Studying the effect of various alkali metals ions on paraquat adsorption... 

Tsai WT, Lai CW, Hsien KJ (2003) Effect of particle size of activated clay on the adsorption of paraquat from aqueous solution. J Coll Interface Sci 263 29-34 Turner A (1996) Trace-metal partitioning in estuaries Importance of salinity and particle concentration. Marine Chemistry 54 27-39... 

The alkylation is achieved using an acid activated clay catalyst (73). The reaction is performed in nitrogen atmosphere. Namely, nitrogen gas atmosphere or other inert gas atmospheres, in contrast to air gas atmosphere, suppress the formation of products that deactivate the clay catalyst. 

Migration of the double bond of terminal alkenes to internal position is favored by the equilibria. Thus 1-butene in the presence of activated clay, silica gel, alumina, or phosphoric acid on pumice may yield equilibrium product mixtures comprised of about 20% 1-butene and 80% 2-butenes.91 The main transformation of branched 1-alkenes under mild conditions is also double-bond migration. For example, 2,4,4-trimethyl-1-pentene is isomerized to the equilibrium mixture92 with 20% 2,4,4-trimethyl-2-pentene when treated with silica gel at 25°C. 

Blending and Heating Raw Materials. The activated clay is blended with the other raw materials and dry-ground, usually in batch or continuous ball mills, to a mean size approaching 15 pm. Typical recipes (in wt%) are ... 

Ref P.P.Sharpe, "The Rifle in America, Funk Wagnails,NY(1947),38-40 Bentonite or Activated Clay. A broad term applied to material which has been derived from volcanic ash in which the mineral Montmorillonite predominates. Bentonite was first recognized in 1898 in Fort Benton(Wyoming) shales and has since been found in thick-bedded deposits over a wide area in Western US(Ref 1)... 

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