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Theoretical and Experimental Investigation of Nanoparticle Formation Via Microemulsion Method

Vafa, Ehsan | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47342 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Shahrokhi, Mohammad; Molaei Dehkordi, Asghar
  7. Abstract:
  8. In this work, nanoparticle production via microemulsion method has been investigated from theoretical and experimental points of view. Population balance approach has been used to model nanoparticle formation in an inverse microemulsion system. The study of nanoparticle formation in the inverse microemulsion system of Marlipal O13/40-cyclohexane-water reveals that in low reactants concentrations, the coagulation phenomenon has an important effect on the formation of particles. In this regard, the population balance equations has been developed to consider the coagulation phenomenon in the inverse microemulsion system. The kernel of coagulation has been calculated based on attractive and repulsive interparticle potentials. The parameters of the developed model has been estimated through an optimization procedure using experimental data available in the literature. Simulation studies reveals that without considering the coagulation phenomenon, formation of bimodal PSD during nanoparticle production cannot be predicted. On the other hand, the effect of reactants concentrations on the flexibility of the surfactant layer around each droplet and the steric hindrance of surfactant molecules during interdroplet collisions have been investigated. These studies reveal that the kinetic parameters of nucleation, growth and coagulation phenomena depend on the reactants concentrations in droplets. Through an experimental study, the effect of reactant concentration, the amount of excess ion and type of surfactant molecules on the final PSD of barium sulfate nanoparticles are also investigated for two inverse microemulsion systems; Triton X-100/cyclohexane/n-hexanol/water and CTAB/cyclohexane/n-hexanol/water. The results of the experiments show that in both systems, the amount of excess ion is not responsible for destabilization of surfactant layer around the droplets, but the concentration of each reactant in the droplets determines the flexibility of the surfactant layer. In addition, through simulation studies, it has been found that the kinetic parameters of the model depend on the reactants concentrations
  9. Keywords:
  10. Microemulsion ; Nanoparticles ; Coagulation ; Modeling ; Population Balance

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