Elemental distribution particle association

Incineration can be applied to all contaminants that have high heat content. It eliminates odor and leachate problems, which are usually associated with landfills, but metals can react with other elements in the feed stream, such as chlorine or sulfur, and form more volatile and toxic compounds. The process has high maintenance and operation costs. Straitz et al. (1995) reported that incineration is a reliable, cost-effective approach to treat VOCs and a wide range of objectionable gas. Chaouki et al. (1995) conducted experiments that examined the effect of fluidized bed combustion on the properties and characteristics of a soil contaminated with PCBs. Particle size distribution and PCB contents were determined before and after a 30-minute incineration. The incineration promoted agglomeration soil, increases in soil pH, and decreases in the PCB content to undetectable levels. 

Referring to the stack filter, the report of the Court of Inquiry (Penney, 1957) stated Iodine vapour had come through the filter but the major part of the particulate material had been caught by the filter . This was published before analyses of the filter material were available, and was incorrect. Most of the activity on the filter was associated with a yellow powder (Crouch Swainbank, 1958). The powder comprised chain aggregates of submicrometre particles of lead and bismuth oxides, which originated as a fume in the reactor. The distribution of fission products on the powder, as between volatile and refractory elements, was similar to that found in the environment. 

If sediment was collected from a particular waterway, the distribution of the element of interest between different components of the sediment was found to vary with the degree of exposure to air and the temperature of any drying stages (Rapin et al., 1986 Kersten and Foerstner, 1986). The minor elements present in sediments (and soils) are not uniformly distributed. Part can be present as mineral fragments derived from the original parent rock, while other parts can be associated with distinct component phases such as carbonate compounds, hydrous oxides of Fe, Al, Mn and organic matter. Some fractions are loosely sorbed on particle surfaces or are held on ion exchange sites. 

In an earlier study (15) we addressed some of the problems in obtaining accurate concentration-vs-particle-size distributions for elements in stack aerosols collected downstream of an electrostatic precipitator and a Venturi wet scrubber at a coal-fired power plant. The problems investigated were error associated with the use of the... 

Contado et al. [4] coupled sedimentation FFF indirectly to GF-AAS as well as directly to ICP-MS to produce element composition data across the size distribution. The high levels of Cu, Pb, Cr, and Cd found were associated with colloidal particles taken from a river situated in a highly industrialized site. The two methods give comparable results, with on-line coupling of ICP-MS having a higher resolution, but ICP-AES yields data for some elements (such as potassium and calcium) where ICP-MS produces interferences. 

Speciation studies have been carried out for methylated species of As, Sb, Ge, and Sn and on different redox states of these elements—As(III-V), Sb(III-V), or Cr(III-VI)— (Andreae and Froehlich, 1984), as shown in Fig. 13.2. In oxic Baltic waters the pentavalent species of As and Sb predominate, while in the anoxic basins the distribution shifts to the trivalent species and possibly also to polysulfide complexes. The methylated species of As, Sb, and Ge are detectable throughout the water column. Since the mid-1980s, an improvement in the understanding of the behavior of trace elements in the Baltic Sea has been achieved. First investigations into the speciation of mercury have been realized by Brugmann (1979) and Brugmann et al. (1991). A special emphasis has been made on the different physicochemical forms, such as dissolved Hg, weakly associated Hg with particles, and total Hg. 

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