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 14

Net energy versus interparticle distance according to DLVO theory, showing the influence of FA (0.14 mg/L) and 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) FA, NaCl, and pH 8.2; (b) FA, NaCl, and pH 10.2; (c) FA, NaCl, and pH 12.2; (d) FA, CaCl₂, and pH 8.2; (e) FA, CaCl₂, and pH 10.2; and (f) FA, 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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