Showing papers in "Journal of Colloid and Interface Science in 1999"

TL;DR: This work has determined the relative importance of parameters as well as the optimal conditions for obtaining uncoated stable particles with an average size of 5 nm and interesting relaxivities and proposed model of synthesis, related to spontaneous emulsification of suspensions, is proposed.

TL;DR: Measurements of the fluid velocity as a function of frequency and position across the electrode indicate that the flow occurs due to electroosmotic stress arising from the interaction of the electric field and the electrical double layer on the electrodes.

TL;DR: It was determined that in situ spectra of both schwertmannite and adsorbed sulfate are quite similar, suggesting that a continuum of outer- and inner-sphere sulfate occurs in both cases.

TL;DR: A simpler general equation is presented that approximates Maugis' solution extremely closely and is amenable to conventional curve fitting software routines and provides a rapid method of determining the value of the "transition parameter" which describes the range of surface forces.

TL;DR: It is maintained that no intermediate phases were positively identified between mono-, di-, and trimers and a range of solid polynuclear phases, which indicates fast polymerisation as the OH/Fe ratio of the system increases.

TL;DR: The effect of ammonia concentration on the region of existence of single-phase water-in-oil microemulsions has been investigated for the system polyoxyethylene (5) nonylphenyl ether (NP-5)/cyclohexane/ammonium hydroxide and shows a complex dependence of the particle size on the water-to-surfactant molar ratio (R) and on the concentration of ammonium Hydroxide.

TL;DR: It is shown that the commonly used 2pK models are incapable to incorporate in the adsorption modeling the correct bidentate binding mechanism found by spectroscopy, and the CD-MUSIC model can successfully describe the macroscopic Adsorption phenomena using the surface speciation and binding mechanisms as found bySpectroscopy.

TL;DR: A kinetic model is described that explains the formation of dispersions of narrow size distribution in such systems of monodispersed colloids from homogeneous solutions and was tested for a system involving formation of uniform spherical gold particles by reduction of auric chloride in aqueous solutions.

TL;DR: It was found that the formation of different polymorphs of calcium carbonate was affected mostly by agitation and concentration of reactants, as well as by the mixing procedure, and the presence of sulfonate or sulfate ions promoted precipitation of vaterite and calcite.

TL;DR: The advantage of this method lies in the formation of a red intermediate during the reduction process, which enables us to prevent the reoxidation of the ferrous ions by adding precipitation agents at the end of the reduction reaction without the protection of nitrogen or argon.

TL;DR: Adsorption by activated red mud (ARM) is investigated as a possible alternative to the conventional methods of Cr(VI) removal from aqueous synthetic solutions and industrial effluents, and promising results are obtained.

TL;DR: The ionic contributions to the electrical conductivity are based on a differential effective medium approach and the influence of the temperature and the presence of a second immiscible and nonwetting phase is also considered in this model.

TL;DR: It is shown that all hydroxyl groups take part in ion exchange and that the unusually small values reported elsewhere with the saturated (de)protonation method may contain errors.

TL;DR: Chitin and chitosan are good removers of cations from aqueous solution and wastewater, but the complexation is probably associated with the lack of order of the chitin polymeric chain or with the freedom of water molecules initially bonded to cations.

TL;DR: A correlation between rheological and electrokinetic results, is shown, and different types of interactions between clay particles are deduced, depending on the pH value of the medium, which means that at acidic medium, there is a dominance of the attractive forces between particles.

TL;DR: The bridging of bivalent metal ions between montmorillonite and humic acid is proposed as the dominant adsorption mechanism.

TL;DR: The main features of a numerical model aiming at predicting the drift of ions in an electrolytic solution upon a chemical potential gradient are presented and applications of the model to more complex problems are presented.

TL;DR: The Lifshitz-van der Waals component of the formamide surface free energy and the electron-acceptor and electron-donor parameters of the glycerol, formamide, and ethylene glycol surfacefree energy determined in the above-mentioned way differ from those determined by van Oss et al. and by Lee.

TL;DR: The rheological properties of aqueous polystyrene latex dispersions from three synthetic batches, with nearly the same z-average particle sizes, 400 nm, but varying degrees of polydispersity, were systematically investigated using steady-state shear and oscillatory shear measurements.

TL;DR: The attachment efficiencies decreased with increasing particle size and bubble size, but increased with particle contact angle and KCl electrolyte concentration, and the values of the induction time obtained are in a reasonable agreement with experimental and calculated induction times reported in the literature.

TL;DR: It is shown that silicone surfactant has an important impact on both the bubble generation and the cell window stabilization stage and that surfactants with higher film elasticity will yield slower drainage rate and better foam cell stability.

TL;DR: The results presented here suggest that control of cake permeability via control of aggregate size and structure is an area with scope for further development though the nature and extent of compaction effects in modifying the fractal properties of aggregates generated in suspension requires attention.

TL;DR: Adsorption of natural organic matter onto seven activated carbons with a wide range of surface properties was studied at high and low ionic strength over a range of pH values and found that, for six of seven carbons, at low surface concentrations, increased Ionic strength decreased NOM adsorption.

TL;DR: All adsorption data, and the results of potentiometric titrations of kaolinite suspensions (alone and in the presence of metals at 100 µM), can be fitted closely by a constant-capacitance surface complexation model that incorporates two bidentate surface complexes.

TL;DR: Three wood-based commercial activated carbons supplied by Westvaco were studied as adsorbents of hydrogen sulfide and show that the combined effect of the presence of pores large enough to accommodate surface functional groups and small enough to have the film of water at relatively low pressure contributes to oxidation of hydrogen sulphide.

TL;DR: In this article, the authors obtained uniform alpha-Fe2O3 particles within the nanometer range (100-300 nm) by precipitation of iron (III) perchlorate in the presence of urea.

TL;DR: Comparison of optimized equilibrium constants for similar surface species showed that model results were consistent with observed sorption behavior: equilibrium constants were highest for compounds having adjacent carboxylic groups, lower for compounds with adjacent phenolic groups, and lowest for compounds in the ortho position relative to a car boxylic group.

TL;DR: This work sets the stage for tractable simulations of particle dynamics in more complex coagulating systems requiring multi-internal (state-) variables for their more realistic and self-consistent description.

TL;DR: It is concluded that the dispersion of nanometer-sized anatase on the surface of the PILC particles and the suspensibility of the particles are the most important factors for high photocatalytic efficiency.

TL;DR: The results indicated that the isosteric heats of water adsorption are affected by the surface heterogeneity only at low surface coverage.