Sulphur accumulation

Lein AYu, Ivanov MV (1983) Reduced sulphur accumulation in sediments of marine basins with high rates of sulphate reduction. In The global biogeochemical sulphur cycle, SCOPE 19. Wiley, Chichester, UK, p 413... 

Some of the measured elements (Ti, Zr and Ba) are mainly components of the T.W.C. acting as catalytic activity promoters or washcoat stabilizers and their content does not change considerably between the fresh and the aged T.W.C. The same happens with another group of elements (Co, Nb, Hf, V, Sr, K and Na), which seems to be rather impurities of the raw materials used in the construction of the T.W.C than contaminants. Sulphur was detected in both aged and fresh catalyst almost in stoichiometry with BaS04, which is the possible form of Ba used as washcoat stabilizer, and it was difficult to separate the quantity of sulphur accumulated as contaminant The rest of the elements (Cr, Ni, Cu, Zn, Mn, Fe, Pb, P and Ca)... 

With drastic Eh increase is associated formation of bog iron ore and aggregations of native sulphur (Figure 3.35). The native sulphur accumulates in discharge surface locations of deep water with high IT S content. In mixing of this water with ground water containing O, with active bacterial participation forms insoluble in water native sulphur, which precipitates and accumulates in rock. 

As well as lowering of pH (in some cases down to 4 0), acidification mobilises aluminium in soluble form into the rivers and lakes (Section 5 5 3) The strength of acidity in affected surface waters can be particularly marked during the first snow melt and in run-off from storms after a dry period This is because an accumulation of strong acid cations (H ) and/or anions has occurred in the catchment area In dry periods sulphur accumulates in dry deposited form which is then oxidised and dissolved by the wet precipitation ... 

PEZET R. and PLANT V. 1977. Elemental sulphur accumulation in different species of fungi. Science, 196, 428-429. 

The fluids contained within petroleum accumulations are mixtures of organic compounds, which are mostly hydrocarbons (molecules composed of hydrogen and carbon atoms), but may also include sulphur, nitrogen, oxygen and metal compounds. This section will concentrate on the hydrocarbons, but will explain the significance of the other compounds in the processing of the fluids. 

Steels and stainless steels show preferential nucleation of pits at inclusions, most notably sulphide inclusions ". Other sulphur-rich regions in ferrous and nickel-based alloys may also lead to premature failure. It has been shown that accumulation of sulphur on the surface of these materials retards passivity and enhances dissolution of the metal. These effects occur in any solution in which the metal shows an active region and they are also preferential pitting sites in the presence of chloride. A recent notion for... 

The presence of active sulphate-reducing bacteria usually results in graphitic corrosion and this has led to a useful method of diagnosing this cause of corrosion. The leaching out of iron from the graphitic residue which is responsible for the characteristic appearance of this type of corrosion leads to an enriched carbon, silicon and phosphorus content in the residue as compared with the original content of these elements in the cast iron. Sulphur is usually lost to some extent but when active sulphate-reducing bacteria are present, this loss is offset by the accumulation of ferrous sulphide in the residue with a consequent increase in the sulphur content of the residue out... 

Environmental benefits of Emission Controls. Information in Figure 5 illustrate that the emission of sulphur in eastern North America has declined over the past decade. This decline allows for a possible verification of the dose-response relationships on which the environmental concerns for emissions have been based. A decline in sulphate deposition in Nova Scotia has apparently resulted in a decrease in acidity of eleven rivers over the period 1971-73 to 1981-82 (47), In the Sudbury, Ontario area where emissions have dechned by over 50% between 1974-76 and 1981-83, a resurvey of 209 lakes shows that most lakes have now become less acidic. Twenty-one lakes that had a pH < 5.5 in 1974-76 showed an average decline in acidity of 0.3 pH units over the period (48), Surveys of 54 lakes in the Algoma region of Ontario have shown a rapid response to a decline in sulphate deposition. Two lakes without fish in 1979 have recovered populations as pH of the water moved above 5.5 (49). Evidence is accumulating to support the hypothesis of benefits that were projected as a consequence of emission controls. This provides increased confidence in the projections. 

Nitrobenzene was submitted to the action of a nitric acid/sulphuric acid mixture. The mixture detonated. It was thought that this accident was caused by a lack of stirring, which caused the reagents to accumulate. A study showed that during this reaction the temperature could reach 2000°C/s. 

SCR for heavy-duty vehicles reduces NOx emissions by 80%, HC emissions by 90% and PM emissions by 40% in the EU test cycles, using current diesel fuel (<350 ppm sulphur) [27], Fleet tests with SCR technology show excellent NOx reduction performance for more than 500000 km of truck operation. This experience is based on over 6 000 000 km of accumulated commercial fleet operation [82], The combination of SCR with a pre-oxidation catalyst, a hydrolysis catalyst and an oxidation catalyst enables higher NOx reduction under low-load and low-temperature conditions [83],... 

Maas FM, De Kok FJ, Kuiper PJC. 1985. The effect of hydrogen sulfide fumigation on various spinach (Spinacia oleracea L.) cultivars Relation between growth inhibition and accumulation of sulphur compounds in the plant. Journal of Plant Physiology 119 219-226. 

E. Hustede, A. Steinbuchel, H. G Schlegel (1993) Relationship between the photoproduction of hydrogen and the accumulation of PHB in non-sulphur purple bacteria, Appl. microbiol. Biotechnol., 39 87-93... 

The metabolism of sulphur plays an important role in metal response, since most chelators, including metallothioneins and phytochelatins, contain this element. APSl encodes an ATP sulfurylase and Brassica juncea has been engineered to constitutively express this gene (Pilon-Smits et al., 1999). The plants showed increased S assimilation, higher glutathione (GSH) levels and were more tolerant to Se, accumulating 2-fold higher Se levels in the shoots. 

Cysteine contributes sulphur atoms to chelators, and therefore the synthesis of cysteine is a further important control point. Cysteine synthase (CSase) is the final enzyme in the biosynthetic pathway. Kawashima and colleagues (2004 and references therein) have produced tobacco plants with altered levels of this protein in the cytosol and/or chloroplasts. All transformants showed enhanced tolerance to Cd, Se and Ni, but not to Pb or Cu. In particular, the plants expressing CSase both in the cytosol and the chloroplasts had an even higher Cd tolerance, and possessed enhanced levels of Cys and GSH. The same plants also accumulated more Cd. 

Sulphur analysis of the liquids and analyses of the used catalysts revealed the same type of trends as are expounded fortiie experiments at 400 C. Therefore, for all of the repeat contact experiments, irrespective of catalyst or experimental condition, constant catalyst activity was achieved after a single contact so that results from single contacts in autoclaves of the design used in this investigation would be representative of steady state liquefaction conditions, enabling the autoclaves to be used for the rapid accumulation of liquefaction data. 

The second reason for acid-digestion is the determination of the total soil elemental content of, e.g. potassium, phosphorus or trace elements. This is seldom done for potassium in normal soil samples, mainly because the total K in soils is of no value as an index to the availability of K to plants, nor is it always of value in tracing the movement or accumulation of applied fertilizer K (Pratt, 1965). The unreactive soil phosphorus is obtained by subtracting the naturally leached reactive phosphorus from the total phosphorus, and a method for determining the latter by extraction with sulphuric acid and potassium persulphate is cited by Turner and FHaygarth (2000). They analysed... 

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