[kolokvij-ijs] Obvestilo o predavanju na Kemijskem inštitutu, Hajdrih ova 19, Ljubljana, 16.5.2002: Prof. dr. Egon Matijev ić

[Eva Tozon]

S Kemijskega inštituta v Ljubljani smo prejeli naslednje obvestilo:
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Z veseljem Vas obveščamo, da bo
16.5.2002 ob 13h v Veliki predavalnici
na Kemijskem inštitutu, Hajdrihova 19, Ljubljana

predaval
Colloid Stability and Complex Chemistry

prof.dr.Egon Matijević

Center for Advanced Materials Processing, Clarkson University,
Potsdam, New York 13699-5814, USA


Most texts deal with colloid stability problems from a strictly theoretical
point of view, i.e. only the effects of interparticle forces on dispersions
are considered. While there is nothing wrong with such an approach, the
results are difficult, if not impossible, to apply to many practical
systems. In this lecture, the problems of colloid stability will be
approached by considering chemical reactions at particle/solution
interfaces. It will be shown that complexing of counterions may greatly
affects the properties of colloids. Depending on the type of the solute
formed, the counterion may become either a more powerful or a less efficient
coagulant. In addition, complexing usually leads to greater adsorptivity
which may often result in charge reversal of colloidal particles. Indeed,
the effects are so striking that in some cases the change in colloid
stability may be utilized to detect and formulate the complex species in
solution. The interactions of hydrolyzed metal ions and of chelating agents
with various colloids will be discussed in detail, with particular emphasis
on the causes of adsorptivity of various complexes on surfaces of different
characteristics, including silver halides, silica, metal oxides, clays, etc.

In addition to colloid stability, the understanding of the interactions of
complex ions at solid/liquid interfaces is essential for the explanation of
many processes in nature and in various applications, such as flotation,
corrosion, adhesion, paper sizing, precipitation, water pollution, etc.