Inorganic deposits

Reclamation, Disposal, and Toxicity. Removal of poisons and inorganic deposits from used catalysts is typically difficult and usually uneconomical. Thus some catalysts are used without regeneration, although they may be processed to reclaim expensive metal components. Used precious metal catalysts, including automobile exhaust conversion catalysts, are treated (often by the suppHers) to extract the metals, and recovery efficiencies are high. Some spent hydroprocessing catalysts may be used as sources of molybdenum and other valuable metals. 

Antifoulants or metal surface cleaners to reduce the risk of pitting corrosion and other forms of concentration cell corrosion initiated at the metal surface by shielding effects from inorganic deposits. These could also be called deposit control agents. 

The importance of the chemical composition of these inorganic deposits in regard to ion emission has been understood for many years and is illustrated by the work of Studier et al. [6]. A deposit of uranium on a hot filament emitted a variety of ions, depending on the oxidizing and reducing agents added to the material. They presented their data in the following format ... 

The Step 2 product (7.36 g) dissolved in 100 ml ethyl alcohol at 0°C was treated with bismuth chloride (2.84 g) followed by three 0.9 g additions of sodium borohydride and the mixture stirred 3 hours at ambient temperature. Ice water was added to the mixture and the crystallized inorganic deposits filtered out through celite. The filtrate was extracted with EtOAc, washed with water and brine, purified as in Step 1, and 7.40 g product isolated as a colorless oil. 

Arranged horizontally or radially in the tree are the wood rays, which, as mentioned earlier, are composed predominantly of small, bricklike, and often living cells called parenchyma see Figures 4, 7, and 11). These cells function in radial translocation but have a major role as a storage receptacle, and frequently contain extraneous materials such as starch, fats, oils, various sugars, and inorganic depositions such as calcium oxalate crystals or silica (Figure 12). 

Peterson, M.N.A. von der Borch, C.C. (1965) Chert modern inorganic deposition in a carbonate-precipitating locality. Science 149, 1501-1503. 

Tropospheric Ozone The Environmental Chemistry of Organotin Compounds Determination of Heavy Metals in Sewage Sludge Inorganic Deposits in Invertebrate Tissues. 

Nitrogen, N2, is a colorless, odorless, tasteless gas that makes up about 75% by mass and 78% by volume of the atmosphere. Nitrogen compounds form only a minor portion of the earth s crust, but all living matter contains nitrogen. The primary natural inorganic deposits of nitrogen are very localized. They consist mostly of KNO3 and NaNOj. Most sodium nitrate is mined in Chile. 

Inorganic ions enhance fouling during water treatment with membranes. In the NF of conventionally treated water, the adsorption of macromolecules was followed by the adhesion of a biofilm. The inorganic deposit was determined to be mainly calcium, phosphorus (due to pretreatment), and... 

Formation of inorganic deposits can take place in principally three different... 

An inorganic deposit can be formed by precipitation onto a surface of a salt from water-soluble ions in the water. Such a deposit is called scale and does not require the presence of other components like organic material or microbiological shme for its formation. 

Formation of the scale nature of inorganic deposits is caused by precipitation of a salt from the water phase of the system. This form of deposit, called scale, is the most common form of inorganic deposits. There are several different types of scales found in the paper industry. Examples are calcium carbonate, calcium sulphate, barium sulphate, aluminium hydroxide and calcium oxalate. All these precipitates are formed because the water solubility of the respective ion pairs is exceeded. 

Calcium carbonate scale is the most common of these three forms of inorganic deposits. It has the appearance of a hard coating on the surfaces of the paper machine or a pulp system, usually discoloured by incorporation of small quantities of other material such as hgnin. 

Fig. 8.1 Refilling of the voided nano-channels of an organic DG template via atomic layer deposition of titania, which is illustrated in the inset. 1 Chemical modification of the styrenic polymer scaffold to introduce functional surface groups and improve the thermal stability. This enables the uniform nucleation of the ALD growth 2 Ideally, the nano-channels are gradually filled until a non-porous layer is formed at the free-surface. 3 This layer is removed by reactive ion etching. 4 Finally, the combined organic/inorganic deposit is calcinated to remove the template and ideally, crystallize the titania...

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