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dc.contributor.advisorValenzuela-Lozano, Fernando Rafael
dc.contributor.advisorBasualto-Flores, Carlos Alfonso
dc.creatorGaete-Carrasco, José Samuel
dc.description.abstractThis PhD thesis entitled "Synthesis of superparamagnetic magnetite nanoparticles functionalized with chemical groups derived from amines and acids. Evaluation of their adsorption effectiveness of lanthanide ions, molybdenum and rhenium in aqueous solution", has as main objective to synthesize and use these materials in the recovery of metallic elements of interest from dilute aqueous solutions. In Chapter 2 the synthesis and characterization of magnetite nanoparticles functionalized were studied. For nanoparticles functionalized with amine derivatives, NPM-AT and NPM-AC2, characterization by HR-TEM indicated average sizes around 6-8 nm. Magnetism curves analysis indicated that both functionalized nanoparticles have superparamagnetic behavior. The zeta potential results evidenced a superficial change on the nanoparticles due to the particles coating, being possible to confirm the amine-derived groups presence in them using FTIR and XPS techniques. For nanoparticles functionalized with acid derivatives groups, NPM-ACO and NPM-APO, the characterization by HR-TEM allowed to determine sizes in 6.8-7.4 nm range. These functionalized nanoparticles showed superparamagnetic behavior. Zeta potential measurements showed a change on the surface of nanoparticles, likely due to the organic coating. FTIR and XPS analysis evidenced the presence of acid derived groups in the nanoparticles. In Chapter 3 the metal ions adsorption effectiveness in aqueous solution using functionalized nanoparticles was studied. In the Re(VII) and Mo(VI) adsorption experiments, NPM-AC2 had a higher adsorption capacity towards both metals compared to NPM-AT. Selectivity studies indicated that both adsorbents present a higher adsorption towards Mo(VI) than for Re(VII) from bimetallic aqueous solutions. In equilibrium studies, a good fit with the three proposed models was achieved, suggesting that the adsorption process with both adsorbents would be governed by a hybrid Langmuir-Freundlich mechanism. With respect to the kinetic6 studies, a pseudo-second order model fitted well the experimental adsorption data of Re(VII) and Mo(VI) using both adsorbents. In addition, desorption studies were carried out, achieving highest desorption efficiency at pH 13. Reuse studies of were also carried out in successive cycles, demonstrating that NPM-AT and NPM-AC2 can be reused at least up to five times. In the second part of Chapter 3, La(III), Pr(III) and Sm(III) adsorption by NPM-ACO and NPM-APO was studied. In all the experiments, NPM-APO presented a higher adsorption capacity towards the three lanthanide ions compared to NPM-ACO. With respect to equilibrium studies, Freundlich model was well adjusted to the experimental data corresponding to the first zone of adsorption curve of the lanthanide ions using NPM-ACO. On the other hand, the three proposed models explained adequately La(III), Pr(III) and Sm(III) adsorption equilibrium behavior using NPM-APO. In kinetic studies it was determined that the pseudo-second order model adequately represents the adsorption kinetics of three lanthanide ions with both adsorbents. Desorption studies indicated that a higher percentage of desorption is achieved at pH 3, using H2SO4 solution. Finally, NPM-ACO and NPM-APO could be reused in at least five cycles. As a conclusion, from the results described in this study, it can be stablished the feasibility of obtaining functionalized nanoparticles which can be used as adsorbents for metal ions recovery and concentration from aqueous solutions.es_CL
dc.relationinstname: Conicyt
dc.relationreponame: Repositorio Digital RI2.0
dc.rightsAttribution-NonCommercial-NoDerivs 3.0 Chile*
dc.titleSynthesis of superparamagnetic magnetite nanoparticles functionalized with chemical groups derived from amines and acids. Evaluation of their adsorption effectiveness of lanthanide ions, molybdenum and rhenium in aqueous solutiones_CL
dc.contributor.institutionUNIVERSIDAD DE CHILEes_CL
dc.subject.oecd1nCiencias Naturaleses_CL
dc.subject.oecd2nCiencias Químicases_CL
dc.subject.oecd3nOtras Especialidades de la Químicaes_CL

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