Up-hill transport

Shukla, J.P., Sonawane, J.V., Kumar, A., and Singh, R.K., Amine facihtated up-hill transport of plutonium(IV) cations across an immobilized liquid membrane. Ind. J. Chem. Tech., 1996, 3 145-148. 

Separation of electrolytes based on the difference in chemical potential across the ion exchange membrane can be classified into (i) diffusion dialysis, (ii) Donnan dialysis, (iii) neutralization dialysis and (iv) up-hill transport. The natural flux of electrolytes through the membrane is low compared with that in the presence of an electrochemical potential. 

Fig. 2 shows the different pathways in which chemical elements contained in rocks are released to the different environmental compartments. Five main processes are responsible for their dispersion into the different ecosystems (1) Weathering, either directly by rain water on rock outcrops, by soil percolation water or by root exsu-dates, which interact with rock fragments, contained in the soil cover (2) Down hill mechanical transport of weathered rock particles, such as creep and erosion and subsequent sedimentation as till material or alluvial river and lake sediments (3) Transport in dissolved or low size colloidal form by surface and groundwater (4) Terrestrial and aquatic plants growing in undisturbed natural situations will take up whatever chemical elements they need and which are available in the surface and shallow groundwater. Trace elements taken up from the soil will accumulate in the leaves and will possibly enrich the soil by litterfall (5) Diffuse atmospheric input by aerosols and rain rock particles from volcanic eruptions, desertic areas (Chester et al., 1996), seaspray and their reaction with rain water. A considerable part of this can be anthropogenic. 

The patterns apparent at both locations indicate that the transport of marine strontium and sulfur decreases with increasing elevation and distance from the coast. The trend is reversed in areas where prevailing winds favor the transport of marine salt up-slope or where excessive melting of snow releases marine salts into the environment. Faure and Jones (1989) noted that the water of McMurdo Sound at Cape Bird is ice-free somewhat longer than at Cape Royds which may explain why the marine component is more abundant at Trachyte Hill (Cape Bird) than at Cape Royds. 

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