Electrostatic , generally mirror

Figure 4.6 shows uptake curves for cations, and analogous curves for anions are their mirror images. There is no generally accepted explanation why the uptake does not reach 0% at sufficiently unfavorable, or the uptake does not reach 100% at sufficiently favorable electrostatic conditions, even at low concentrations of the solute. Formation of very stable ternary surface complexes involving impurities on the one hand and formation of complexes with products of dissolution of the adsorbent on the other have been discussed as possible rationale, but some examples of unusual results can be also due to experimental errors (inadequate phase separation). Figure 4.6(C) shows two types of uptake curves with a maximum. Such uptake curves are observed for cations in the presence of carbonates (or other weak acids), which form stable complexes with a metal cation of interest. At low pH these ligands are fully protonated, and they do not compete with the surface for metal...

The electron mirror microscope is still a research instrument. It has a rather low resolution (about 800 A), and the electrostatic lens used gives problems. It is particularly suited for examination of electric and magnetic patterns, but is not yet an instrument of general utility. 

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