Particle formation transport controlled systems

Over the years, the precipitation of iron oxides and hydroxides from acidic solutions has received considerable attention in various fields, such as catalyst synthesis, environmental sciences and industrial processes [e.g. 22-29]. Freshly formed iron hydroxide particles help to control pollution in aquatic systems, e.g. by fixation and transport of phosphates, heavy metals and other reactive inorganic and/or organic species [30-33]. The high reactivity of these iron phases is mainly due to their small size. The formation and aggregation of iron colloids, which occurs in continental and marine aquatic systems [22, 34-38], is also employed in water and wastewater treatments [35, 39,40]. 

Particle formation processes can further be subdivided into transport-and reaction-controlled processes. Typically one assumes that the synthesis in the gas phase is not controlled by any mass transfer limitations, whereas mass transfer issues are very common in liquid phase synthesis. Prior discussing mixing and reaction-controUed systems in more detail, it needs to be mentioned that perfect stabilization is assumed for the time being. Effects of coagulation would completely change the PSD. 

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