Sulfate containing particles

One example that has received considerable attention in recent years is the origin and fate of atmospheric sulfate particles. There is reason to believe that SO2 gas released in one region appears 100 km and farther from its source in the form of sulfuric acid and other sulfate-containing particles. Both homogeneous and heterogeneous nucleation are of clear importance in its initial formation. 

Fig. 6.4 Schematic illustration of the key pathways in the atmospheric cycle of S involving (7) the natural emissions of reduced S compounds such as H2S frran terrestrial biota and dimethyl sulfide (CH3SCH3) from oceanic biota (2) anthropogenic emissions of S compounds, principally SO2 (3) the oxidation of reduced S compounds by OH and other photochemical oxidants leading to the production of intermediate oxidation state S compotmds such as SO2 and methane sulfonic acid (MSA) (4) the oxidation of these mtermediate oxidation state compounds within the gas phase by OH-producing H2SO4 vapor (5) the conversion of intermediate oxidation state compounds within liquid could droplets, which upon evaporation yield sulfate-containing particles (6) the conversion of H2SO4 to sulfate-containing particles and (7) the ultimate removal of S fiom the atmosphere by wet and dry deposition (Chameides and Perdue 1997)...

Flame photometry has promise for the measurement of sodium, lead, and potassium. An application to measurement of sodium and alkali metals has been reported. The continuous measurement of sulfur-containing particles has received considerable attention. The motivation for observation of sulfur-containing particles comes from concern about the potential hazard posed by sulfate in the atmosphere. 

The first reported work on the adsorption of ODNs onto charged colloids revealed marked affinity differences between sulfate- and amino-containing polystyrene latexes. In fact, low affinity has been observed for sulfated polystyrene particles, whereas high affinities are exhibited in the case of cationic (amine and amidine) polystyrene latexes (Fig. 2). 

In continental air sulfate tends to be associated with finer particles, and as ammonia is more likely to be present in the air this can neutralize the sulfuric acid with the formation of ammonium sulfate- or bisulfate-containing particles over land. Sulfuric acid can displace chloride from seasalt aerosols and represent a source of hydrogen chloride ... 

Milford, J.B. Davidson, C.l. "The sizes of Airborne Sulfate- and Nitrate-Containing Particles A Review" 1985, manuscript in preparation. 

The study of the atmospheric sulfur cycle is a rapidly expanding field because human activity provides an important sulfur dioxide source. In the atmosphere S02 is converted to sulfate containing aerosol particles which can modify the radiation balance of the Earth-atmosphere system, the optical properties and the precipitation forming ability24 of the air. 

Following reactivation by SO2 at 500°C, STEM examination (Figure 4) showed large Pb-containing particles with sizes up to 10.000A. Since XRD showed that the only crystalline Pb species present was PbSO, these large particles are concluded to be PbSO. In the IR spectrum of this reactivated disc, a large sulfate band was observed at 1390 cm-1. EDX consistently showed lower Pb levels in the Pt particles after reactivation. 

The first recognized type of air pollution was that typified by high concentrations of sulfur compounds (SOj and sulfates) and particles, resulting from combustion of coal and high-sulfur-containing fuels. Cities with this characteristic type of air pollution are often in cold climates where electric power generation and domestic heating are major sources of emissions. 

Reverberator Furnace. Using a reverberatory furnace, a fine particle feed can be used, the antimony content can be controlled, and batch operations can be carried out when the supply of scrap material is limited. However, the antimony-rich slags formed must be reduced in a blast furnace to recover the contained antimony and lead. For treating battery scrap, the reverberatory furnace serves as a large melting faciUty where the metallic components are hquefted and the oxides and sulfate in the filler material are concurrently reduced to lead metal and the antimony is oxidized. The furnace products are antimony-rich (5 to 9%) slag and low antimony (less than 1%) lead. 

Copper-containing lead alloys undergo less corrosion in sulfuric acid or sulfate solutions than pure lead or other lead alloys. The uniformly dispersed copper particles give rise to local cells in which lead forms the anode and copper forms the cathode. Through this anodic corrosion of the lead, an insoluble film of lead sulfate forms on the surface of the lead, passivating it and preventing further corrosion. The film, if damaged, rapidly reforms. 

Extraction of Bertrandite. Bertrandite-containing tuff from the Spor Mountain deposits is wet milled to provide a thixotropic, pumpable slurry of below 840 p.m (—20 mesh) particles. This slurry is leached with sulfuric acid at temperatures near the boiling point. The resulting beryUium sulfate [13510-49-1] solution is separated from unreacted soflds by countercurrent decantation thickener operations. The solution contains 0.4—0.7 g/L Be, 4.7 g/L Al, 3—5 g/L Mg, and 1.5 g/L Fe, plus minor impurities including uranium [7440-61-1/, rare earths, zirconium [7440-67-7] titanium [7440-32-6] and zinc [7440-66-6]. Water conservation practices are essential in semiarid Utah, so the wash water introduced in the countercurrent decantation separation of beryUium solutions from soflds is utilized in the wet milling operation. 

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