Colloid Systems and Interfaces Stability of Cerium Oxide Nanoparticles in Aqueous Environments: Effects of pH, Ionic Composition, and Suwanee River Humic and Fulvic Acids

Figure 6

Net energy versus interparticle distance according to DLVO theory, showing the influence of representative monovalent electrolyte NaCl or divalent electrolyte CaCl₂ concentrations varying from 0 to 1 mM at pH 8.2, pH 10.2, and pH 12.2, for CeO₂ NPs suspended in aqueous systems: (a) NaCl and pH 8.2; (b) NaCl and pH 10.2; (c) NaCl and pH 12.2; (d) CaCl₂ and pH 8.2; (e) CaCl₂ and pH 10.2; and (f) CaCl₂ and 12.2. Calculation of DLVO theory includes the contributions of the van der Waals and electric double layer (EDL) interactions. The net energy (Net) shown is the sum of EDL repulsion and van der Waals attraction between two approaching particles.

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