Investigation of the coagulation and adhesion phenomena in colloids by Field-Flow Fractionation

Conventional and potential barrier methodologies of Field-Flow Fractionatio n are used to separate and characterize colloidal particles of haematite an d titanium dioxide. The colloidal particles are reversibly adsorbed at the beginning of the Sed imentation Field-Flow Fractionation channel wall. The reversibility of the adsorption of these particles can be achieved by the appropriate adjustment of various parameters among which the must suitable is the ionic strength of the carrier solution. In the present work by using both Field-Flow Fractionation (FFF) and Transm ission Electron Microscopy (TEM) techniques we investigate whether the reve rsible adsorption of the haematite and titanium dioxide particles on the st ainless-steel channel wall is due to their reversible coagulation or to the variation of the interaction forces between the colloidal particles and th e solid surface.