Sulfate accumulation

The secondary pickle reservoir is also shown in Block B. Copper sulfate accumulates in this bath and eventually crystallizes out. These crystals can be recovered and sold as a copper-rich sludge or added to the electrolytic copper recovery loop. 

For the vanadophore region, the sulfate concentration has been estimated to be of the order of 1.3 M and pH 2.349 With no evidence for a stable complex within the vanadocyte, Figure 14 depicts an interesting mechanism proposed for vanadium and sulfate accumulation.350 Anionic vanadium(V) (as HVO ") and sulfate ions enter the cell. Provided that within the vanadophore there is a strong reducing agent, vanadium can be reduced to vanadium(IV) and vanadium(III), cationic at the low pH in the vanadophore. If the vanadophore membrane is permeable to anions but not cations, the reduced vanadium remains trapped. 

This "Hurler corrective factor" was identified as an a-L-iduronidase. In the Hunter syndrome (MPS II) dermatan sulfate and heparan sulfate accumulate. 

Zettersten, E., et al. Recessive x-linked ichthyosis Role of cholesterol-sulfate accumulation in the barrier abnormality. J Invest Dermatol 111 784. 

Figure 2. Radioactivity chromatogram of sulfur compounds derivatized with monobromobimane. The reversed-phase HPLC separation is based on the hydrophobic properties of the bimane-sulfur adducts but peak area is based on "S-radioactivity of the compounds. At time 0 sulfite and thiosulfate impurities are present before addition of the hepatopancrease tissue homogenate. This was a 60 min experiment to determine the sulfide detoxifying functions of the hepatopancrease of the hydrothermal vent crab Bythograea thermydron. During this time the proportion of radioactivity in sulfide rapidly decreases and thiosulfate and sulfate accumulate as end products. Two intermediates, pi and p2 accumulate then decrease during the experiment. The two intermediates are believed to be polysulfides based on similar elution times of polysulfide standards. (Figure is the unpublished chromatograms from the data in Vetter et al. (24)-) continued on next page.

LeeJK, Marion T, AbeK, LimC, PollackGM, Brouwer KL. Hepatobiliary disposition of troglitazone and metabolites in rat and human sandwich-cultured hepatocytes Use of Monte Carlo simulations to assess the impact of changes in biliary excretion on troglitazone sulfate accumulation. f Pharmacol Exp Ther. 2010 332(l) 26-34. 

Cerebrosides other than sulfatides are decreased ceramide dihexoside sulfate accumulates. 

Estimating the deposition velocities of gaseous species is considerably more complex than estimating those for substances in particles, in part due to the uncertainties in the sticking and reaction probabilities. Such estimates have not been made but the potential effects of some of the typical gases can be surmised from available data on surface accumulation rates, e.g. sulfate accumulation on indoor zinc and aluminum surfaces is predominantly a result of particulate sulfate deposition rather than a corrosion reaction involving sulfur dioxide (0. 

Mechanism of Lead Sulfate Accumulation During HRPSoC Duty... 

Recent investigations conducted by CSIRO [7,8] have provided the following explanation for the mechanism of lead sulfate accumulation in negative plates during HRPSoC duty. 

If the gas has not been adequately cleaned, the contact section of the plant will have continuing operating problems. Improper operation of the mist precipitators will permit acid mist to enter the contact section. This will result in corrosion and sulfate accumulation in the gas ducts, the blower, and the heat exchangers. The corrosion is particularly severe in the heat exchangers because the tube wall temperature, with hot sulfur trioxide gas in the tubes, exceeds 300 °F. The sulfate accumulation on the duct walls is normally not a serious corrosion problem but it eventually breaks loose and is carried onto the catalyst beds in the converter. This sulfate, and also any dust that may pass through the purification section, will gradually blind the catalyst beds. This reduces the conversion efficiency and increases the pressure drop through the plant. 

Equation 3 is found never to go to completion as soon as enough sulfate accumulates Equation 4 is activated and the droplet is blown apart violently. In poorly formulated, mixed or formed glitter, one can observe spritzels which are not entirely reacted. These spritzels, if large enough, yield interesting debris for microscopic study. 

Iduronale-2-sutfatase (EC 3.1.6.13). Heparan sulfate and dermatan sulfate accumulate. No clouding of cornea. Heart involvement rare. Mental retardation less than in typelu. Fadal features similar to type 1h- lype Ilg slightly less severe than IIa... 

Heparan ti-sulfalase. Heparan sulfate accumulates. No clouding of cornea. Heart not affected. Skeleton only slightly affected. Facial features similar to type but less severe. 

Glucosamine N-aceiyltransferase (EC 2.3.1.3). Heparan sulfate accumulates. Facial features similar to typelll. ... 

H-Acetyiglucosamme-6-sulfatase (EC 3.1.6.14). Heparan sulfate accumulates. Mild osteochondnxtystro-phy, and presence of hypoplastic odontoid proccss. Fadal features similar to type III a-ViPt mucopolysaccharidosis, or Morquio-Brailsfordsyndrome (variant 1) (see Fig.2). 

P-Galactosidase (EC 3.2.1.23). Enzyme has high for keratan sulfate and normal K for gangliosides. Keratan sulfate accumulates. No mental retardation. Enamel normal. Only mild bone changes. Heart involvement rare. Cornea clouded. Facial features normal and unaffected. 

Ji-Acetylgalactosamine-4-sulfalase (EC 3.1.6.12). Dermatan sulfate accumulates. No mental retardation. Heart affected in some cases. Facial features less severely affected than in type 1. In type VI skeletal involvement is similar to type Ih wiAout vertebral deformation. Vlg and VI( show moderate and mild skeletal effects, respectively. 

Glucuronidase (EC 3.2.1.31). Chondroitin 4-sulfate and chondrotin 6-sulfate accumulate. Dermatan sulfate and/or heparan sulfate sometimes also accumulate. Mental retardation not severe. Cornea sometimes clouded. Facial appearance may resemble type Ih, or may be less severely affected, or normal. Skeletal deformities usually very marked. Heart not affected... 

Acylsphingosine deacylase (ceramidase) (EC 3.5.1.23). Ceramide, glycolipids and sometimes dermatan sulfate accumulate subcutaneously, in tendons (especially at joints), and in neurons. Swollen joints and subcutaneous nodules. Growth retardation. Death usually at age 7-22 months, but some survivors. 

Except in aqueous melts, molten bisulfates, and melts exposed to hydrogen atmospheres, the hydrogen ion is of little importance in molten systems, which can generally be regarded as aprotic solvents. Rather, it is the oxide ions which are of central importance in corrosion schemes. This is particularly so in oxyanionic melts, wherein acidity and basicity are best defined according to the Lux-Flood formalization (see earlier). Thus, for example, when a deposit of molten sulfates accumulates on boiler tubes, it arises through the corrosion equilibrium ... 

For a lifetime of 20 years, the sulfate accumulation is expected to reach 3000 pg/cm. (It should be noted that electric fields can increase this deposition rate by as much as 100 but this effect is ignored here.)... 

Anodic spots surrounded by cathodic areas are created during the initiation period. With an electrolyte film on the metal surface conditions are created for the beginning of the corrosion process, which is further stimulated when SO2 is adsorbed and oxidized in the rust layer as SO4". Sulfate accumulates... 

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