Fractionation, particulate metal

The data presented in Table 11.1 indicate that the fluvial gross river flux is the major source of trace metals to the oceans and that most of this flux is in particulate form (fluvial gross particulate flux). But the majority of this particulate flux is trapped within estuaries, primarily via settling, and, hence, is not released into the open ocean. As a result, the fluvial net particulate flux is only about 10% of the fluvial gross particulate flux. In seawater, most of this particulate metal remains in solid form due to low solubilities. The particulate metals eventually settle to the seafloor and are subsequently buried in the sediments. In the case of iron, a small fraction of the particulate pool does dissolve. In the surface waters, solubilization of particulate iron can provide a significant amount of this micronutrient to the phytoplankton. 

Sinking particles transport trace elements to the sediments. Once in the sediments, chemical reactions can resolubilize a significant fraction of the particulate metals. This process is termed diagenetic remobilization and is the subject of the next chapter. The resolubilized elements can diffuse across the sediment-water interface into the deep zone. 

Weinstein, S.E. and S.B. Moran. 2004. Distribution of size-fractionated particulate trace metals collected by bottles and in-situ pumps in the Gulf of Maine-Scotian Shelf and Labrador Sea. Mar. Chem. 87 121-135. 

Suspended particulate matter and marine organisms are present in seawater. In seawater analysis, it is desirable to separate the particulate and dissolved fractions, and to analyse them separately. A comparison of analytical results for filtered and unfiltered seawater is shown in Table 3 [15], where upper and lower limits of particulate metal concentrations are also given. As can be seen in Table 3, the contents of particulate trace metals are less than 1% of the total metal concentration, which is generally within... 

The viscosity range of crude and lubricating oils can vary significantly from different location sources and the distilled version. The determination of metals is necessary prior to refining and cracking/fractionation . The metals are present as inorganic particulates... 

Considering dissolved and particulate Pb, Cd, Cu, and Zn and total Hg (Table 13.3) between 1993 and 2000, the mean metal concentrations of e dissolved and the particulate metal fractions were higher in e Western Baltic Sea, with the exception of Cudiss. It is noticeable at up to 68 % of Pb, 34% of Cd, and 27% of Cu were associated with suspended particulate material (SPM) in the Western Baltic Sea, while for the Baltic Proper this proportion had decreased. 

Figure 2 The fraction of metal in the dissolved phase (fd) as a function of the concentration of suspended particulate matter (SPM). The bands at the top of the diagram represent the general ranges of SPM concentrations from the open ocean through to the estuarine turbidity maximum zone (TMZ). The numbers next to the lines are values of the partition coefficients, Kb, used to estimate the value of Metals are associated with their typical Kd values and are shown next to the appropriate line.

Table VIII. Particulate Metal Fractionation at Nonurban Sites in the Upper Mississippi River—1977—1978 ...

Sohd rocket propellants represent a very special case of a particulate composite ia which inorganic propellant particles, about 75% by volume, are bound ia an organic matrix such as polyurethane. An essential requirement is that the composite be uniform to promote a steady burning reaction (1). Further examples of particulate composites are those with metal matrices and iaclude cermets, which consist of ceramic particles ia a metal matrix, and dispersion hardened alloys, ia which the particles may be metal oxides or intermetallic compounds with smaller diameters and lower volume fractions than those ia cermets (1). The general nature of particulate reinforcement is such that the resulting composite material is macroscopicaHy isotropic. 

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