Colloidal hematite

Amal, R. Coury J.R. Raper, J.A. Walsh,W.P. Waite, T.D. (1990a) Structure and kinetics of aggregating colloidal hematite. Colloids Surfaces 46 1-19... 

Andrade, E.M. Molina, F.V. Gordillo, G.J. Posadas, D. (1994a) Adhesion of colloidal hematite onto metallic surfaces. II. Influence of electrode potential, pH, ionic strength, colloid concentration, and nature of the electrolyte on the adhesion on mercury. J. Colloid Interface Sci. 165 459-466... 

Buxton, G.V. Rhodes, T. Sellers, R.M. (1982) Radiation-induced dissolution of colloidal hematite. Nature 295 583-585... 

Buxton, G.V. Rhodes,T. Sellers, R.M. (1983) Radiation chemistry of colloidal hematite and magnetite in water reductive dissolution by 1-mefhylefhanol radicals (EDTA) iron(ll). J. Chem. Soc. Faraday Trans. 1. 79 2961-2974 Bye, G.C. Howard, C.R. (1971) An examination by nitrogen adsorption of the thermal decomposition of pure and silica doped goefhite. J. Appl. Chem. Biotechnol. 21 324-329... 

Hesleitner, P. Babic, D. Kallay, N. Matijevic, E. (1987) Adsorption at solid/solution interfaces. 3. Surface charge and potential of colloidal hematite. Langmuir 3 815-820 Hesleitner, P. Kallay, N. Matijevic, E. (1991) Adsorption at solid/liquid interface. 6. The effect of methanol and ethanol on the ionic equilibrium at the hematite/water interface. Langmuir 7 178-184... 

Johnson, J.E. Matijevic, E. (1992) Interactions of proteins with uniform colloidal hematite and chromium hydroxide particles. II. Stability and mobility. Colloid Polymer Sd. 270 364-369... 

Penners, N.H.G. (1985) The preparation and stability of homodisperse colloidal hematite (a-Pe203). Ph.D. Thesis Wageningen, The Netherlands, 97 p. 

A.V. (1997) Adsorption of a corticoid on colloidal hematite particles of different geometries. J. Colloid Interface Sd. 187 429-434 Verdonck, L. Hoste, S. Roelandt, F.F. Van der Kelen, G.P. (1982) Normal coordinate analysis of a-FeOOH - a molecular approach. J. Molecular Structure 79 273-279 Vermilyea, D.A. (1966) The dissolution of ionic compounds in aqueous media. J. Electro-chem. Soc. 113 1067-1070 Vermohlen, K. Lewandowski, H. Narres, H-D. Schwager, M.S. (2000) Adsorption of polyelectrolytes onto oxides - the influence of ionic strength, molar mass and Ca " ions. Coll. Surf. A 163 45-53... 

Dtsch. Bodenkl. Gesell. 59/1 505—510 Zelenev, A. Matijevic, E. (1997) Effect of surfactants on particle adhesion. Part I Interactions of monodisperse colloidal hematite particles with glass beads in the presence of sodium 4-octyl benzene sulphonate. Coll. ... 

Ozaki, M., Egami, T., Sugiyama, N., and Matijevic, E., Agglomeration in colloidal hematite particles due to weak magnetic interactions, J. Colloid Interface Sci., 126, 212, 1988. 

A study of microwave effects on the formation of nanoparticles in the hydrolysis reaction of FeCl3 with NaH2P04 to get spindle-type colloidal hematite particles under microwave radiation, was reported by Han and coworkers [183]. They found that the reaction rate increased greatly, and the reaction conditions, for example, the acidity of the solution, concentration ratio of the components, and the micro-wave radiation time, had important effects on the nanoparticle formation and their morphology. They discussed the roles of microwaves and the concentration of H2P04 during the hydrolysis process. 

Cromieres, L. et al., Physico-chemical characterization of the colloidal hematite/ water interface Experimentation and modelling, Colloids Surf A, 202, 101, 2002. 

Hesleitner, P. et al.. Adsorption at solid/solution interfaces. 3. Surface charge and potential of colloidal hematite, Langmuir, 3, 815, 1987. 

Gunnarsson, M. et al.. Sorption studies of cobaltfll) on colloidal hematite using potentiometry and radioactive tracer technique, J. Colloid Interf. Sci., 231, 326, 2000. 

Chang, H.C.. Healy, T.W., and Matijevic, E., Interaction of metal hydrous oxides with chelating agents. III. Adsorption on spherical colloidal hematite particles,... 

We have chosen hematite oxalate as a model system, since the photochemical properties of colloidal hematite (Stramel and Thomas, 1986) and the photochemistry of iron(III) oxalato complexes in solution (Parker and Hatchard, 1959) have been studied extensively. The experiments presented in this section were carried out as batch experiments with monodispersed suspensions of hematite (diameter of the particles 50 and 100 nm), synthesized according to Penners and Koopal (1986) and checked by electron microscopy and X-ray diffraction. An experimental technique developed for the study of photoredox reactions with colloidal systems (Sulzberger, 1983) has been used. A pH of 3 was chosen to maximize the adsorption of oxalate at the hematite surface. This case study is described in detail by Siffert (1989) and Siffert et al. (manuscript in preparation). 

The particle sol and filtration samples were diluted 1 1 with HCl (36 /o) and heated (in a closed sample vial) to dissolve the colloidal hematite. These samples were then analysed directly. 

Inorganic colloids (hematite, 75 nm) did not cause irreversible flux decline. Pretreatment of the solutions using ferric chloride not only prevented flux decline under criticalfouling conditions (high calcium concentration and IHSS HA), but also influenced rejection. The latter depends on the charge of the ferric hydroxide precipitates. Cation rejection increased when positive ferric hydroxide colloids were deposited on the membrane, which the organic rjection decreased. 

When colloidal hematite particles are present (Table 8.10) the effect of ferric chloride dosing is smaller and resistances are highest for the 100 kDa membrane. In the presence of the hematite colloids it appears as if permeation drag becomes important and pressure plays a minor role. 

Vigorous stirring was applied during the addition of ferric chloride to the solution. For the small colloids (hematite IV, 40 nm), the solution needs to be excessively saturated to ensure very high... 

Amal R. (1991), Fractal structure and kinetics of aggregating colloidal hematite, PhD Thesis, UNSW, Chemical Engineering, 1991. 

P Vera, V Gallardo, 1 Salcedo, A V Delgado. Adsorption of a conicoid on colloidal hematite particles of different geometries. J. Colloid Interface. Sci. 187 429-434, 1997,... 

Andrade, E. M., F. V. Molina, and D. Posadas. 1999. Adhesion of colloidal hematite onto mercury in water-ethanol media. Journal of Colloid and Interface Science 215, no. 2 370-380. 

Analogous results were obtained with Co2+ ions in contact with colloidal hematite (a-Fe203) [8,9], and the same effects can be expected with other unhydrolyzed cations that would react with surface =MOH sites, as long as strong bonds are formed by the substitution with protons. 

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