The transition metal ferrites of composition MFe2O4 where M is Fe, Co, or Ni are well established materials for various biological applications due to their interesting magnetic properties. Their elemental and stochiometric composition can be easily manipulated which allows further tuning of their ferrimagnetic properties. By changing the identity of M and by changing the crystallite size of the ferrites, nanocrystals with diverse magnetic properties can be systematically produced. Furthermore, ferrites are more stable in diverse chemical environments, as compared to metallic nanoparticles, which make ferrites particularly useful for a broad range of biomedical applications, especially in the field of magnetic resonance imaging and cell labeling. In this work, spinel ferrites of composition CoFe2O4, NiFe2O4, and Ni.5Co.5 Fe2O4 were synthesized by a polyol method utilizing ethylene glycol as the solvent, reducing agent, and surfactant. The nanoparticles produced were surface coated with 3-aminopropyltriethoxy silane to increase solubility as well as to serve as an anchor for further conjugation with targeting substrates such as peptides and antibodies. The first part of this dissertation was focused on using the polyol method to produce nanoparticles of various metallic compositions. In each case, the polyol method provided an easy one-pot method to produce metallic as well as metal oxide nanocrystals. Utilizing the polyol method, ferrites of CoFe2O4, NiFe2O4, and Ni.5Co.5 Fe2O4 were produced with size ranges between 20 nm and 50 nm depending on the reaction time in the polyol. The second part of this dissertation was concerned with the functionalization of the nanoparticles to serve as an anchor for further conjugation with targeting substrates in the immunoaffinity separation of food borne pathogens. These nanoparticles were functionalized using an anti-E. coli O157:H7 antibody, mixed with a food matrix, and then subsequently removed from the food matrix by an external magnet in order to be analyzed by Matrix Assisted Laser Desorption Ionization/Time of Flight (MALDI/TOF) Mass Spectrometry as a rapid identification method of bacterial pathogens. Furthermore, magnetic resonance imaging (MRI) was carried out on the polyol produced ferrites in order to measure the transverse relaxation time (T2) of the nanoparticles in order to investigate the size dependence and crystallite composition of the particles ability to affect the transverse relaxivity rarte (r2). Further understanding of how ferrite composition and crystallite size affect their magnetic properties and resulting MRI contrast abilities will provide insight into the best materials for the next generation of contrast agents. Lastly, the ability of nanoparticles to serve as a stationary phase material for reversed phase ultrahigh pressure liquid chromatography will be discussed as a novel separation technique.

Magnetic nanoparticles attract increasing attention because of their current and potential biomedical applications, such as, magnetically targeted and controlled drug delivery, magnetic hyperthermia and magnetic extraction. Increased magnetization can lead to improved performance in targeting and retention in drug delivery and a higher efficiency in biomaterials extraction. We reported an approach to synthesize iron contained magnetic nanoparticles with high magnetization and good oxidation resistibility by pyrolysis of iron pentacarbonyl (Fe(CO)[subscript 5]) in methane (CH[subscript 4]). Using the high reactivity of Fe nanoparticles, decomposition of CH[subscript 4] on the Fe nanoparticles leads to the formation of nanocrystalline iron carbides at a temperature below 260°C. Structural investigation indicated that the as-synthesized nanoparticles contained crystalline bcc Fe, iron carbides and spinel iron oxide. The Mössbauer and DSC results testified that the as-synthesized nanoparticle contained three crystalline iron carbide phases, which converted to Fe[subscript 3]C after a heat treatment. Surface analysis suggested that the as-synthesized and subsequently heated iron-iron carbide particles were coated by iron oxide, which originated from oxidization of surface Fe atoms. The heat-treated nanoparticles exhibited a magnetization of 160 emu/g, which is two times of that of currently used spinel iron oxide nanoparticles. After heating in an acidic solution with a pH value of 5 at 60°C for 20 h, the nanoparticles retained 90 percentage of the magnetization. / Singapore-MIT Alliance (SMA)

Recently, metal nanoparticles have attracted the attention of researchers in several fields of study due to their high surface area and other unique properties. Using metal nanoparticles as a component of an in situ chemical oxidation (ISCO) system is emerging and hence very little information is available. In this research, nano zero valent iron (nZVI) particles and iron-based bimetallic zero valent nanoparticles (BZVNs) were employed to activate some common peroxygens (hydrogen peroxide (H2O2), persulfate (S2O82-), and peroxymonosulfate (HSO5-)) to degrade hazardous organic compounds. Aqueous and soil slurry batch systems were used along with a one-dimensional physical model. The results from the aqueous batch systems showed that nZVI is a promising activator for S2O82- compared to other conventional iron activators (e.g., granular-ZVI and Fe2+). For example, the initial trichloroethylene (TCE) reaction rate by nZVI activated S2O82- was 1.11 x 10-4 M L-1 min-1 compared to an initial reaction rate of 6.25 x 10-5 M L-1 min-1, 5.18 x 10-6 M L-1 min-1, and 1.8 x 10-7 M L-1 min-1 for Fe2+ activated S2O82-, granular-ZVI activated S2O82-, and non-activated S2O82-, respectively. However, the surfaces of nZVI particles were passivated quickly following exposure to S2O82-, causing the reaction rate to reduce to a magnitude representative of an un-activated S2O82- system. An iron-sulfate (FeSO4) complex was formed on the surfaces of the nZVI particles following exposure to S2O82- compared to the iron oxyhydroxide (FeOOH) layer that was present on fresh nZVI surfaces. BZVNs showed better treatment effectiveness than nZVI particles as activators for H2O2, S2O82-, and HSO5-. For example, the TCE reaction rate constant for nano-Ag-Fe0 activated H2O2 was 9 to 18 fold higher than that for nZVI activated H2O2. Of the nine different BZVNs investigated as activators, the greatest TCE degradation was achieved by nano-Pd-Fe0 and nano-Zn-Fe0 activated S2O82- system, nano-Co-Fe0 activated HSO5- system, and nano-Ag-Fe0 activated H2O2 system. For all of these systems, an increase in the dosage of nanoparticles and peroxygens increased TCE degradation. The activated H2O2 system showed a lower TCE degradation rate compared to either the activated S2O82- or the activated HSO5- systems, suggesting that a bridged group complex is formed between the activators and H2O2. The dissolved TCE concentration remaining in the soil slurry batch systems after using the nano-Pd-Fe0 activated S2O82- system was two to three fold higher than that in an aqueous batch system. Furthermore, for five different aquifer materials used, the higher mass of aquifer materials the lower the TCE degradation, indicating that the aquifer materials compete with a target organic compound in the presence of activated S2O82-. A linear relationship was observed between the organic carbon (OC) content and the initial TCE decomposition rate. Although there is no direct evidence of the effect of OC on the treatment system, it is suggested that the OC may result in scavenging the generated free radicals or by directly consuming persulfate. In the one-dimensional physical model systems, bimetallic nanoparticles were mobile in a non-geological porous medium and relatively immobile in a geological porous medium. In the non-geological porous medium, we found that adding a second metal (e.g., Pd) to nano-Fe0 particles significantly improved their functionality and performance (e.g., mobility and suspension). For example, the results from mobility experiments using columns packed with glass beads showed that the effluent iron concentration was <6 % of the influent iron concentration for the nano-Fe0 particles, while it was ~100 % for the nano-Pd-Fe0 particles. In the geological porous medium, based on visual inspection, nano-Pd-Fe0 particles could not travel more than a few centimeters into columns packed with CFB Borden sand, and no iron was detected in the effluent. To overcome the delivery issue in porous media, nano-Pd-Fe0 particles were injected to create a zone of activation to activate S2O82- for the treatment of TCE source zone. However, we found that the TCE mass destruction was only 9 % higher in the nano-Pd-Fe0 activated S2O82- system compared to the non-activated S2O82- system as revealed by the effluent chloride concentration. In addition, the activation zone composed of nano-Pd-Fe0 particles was rapidly deactivated after exposure to persulfate as visually observed by color change, indicating that the longevity of the activation zone is limited. This research effort provides a contribution to the field of ISCO by evaluating the potential utility and applicability of a new class of activators for some common peroxygens.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 58-59). Also available in electronic version. Access restricted to campus users.

Recently, metal nanoparticles have attracted the attention of researchers in several fields of study due to their high surface area and other unique properties. Using metal nanoparticles as a component of an in situ chemical oxidation (ISCO) system is emerging and hence very little information is available. In this research, nano zero valent iron (nZVI) particles and iron-based bimetallic zero valent nanoparticles (BZVNs) were employed to activate some common peroxygens (hydrogen peroxide (H2O2), persulfate (S2O82-), and peroxymonosulfate (HSO5-)) to degrade hazardous organic compounds. Aqueous and soil slurry batch systems were used along with a one-dimensional physical model. The results from the aqueous batch systems showed that nZVI is a promising activator for S2O82- compared to other conventional iron activators (e.g., granular-ZVI and Fe2+). For example, the initial trichloroethylene (TCE) reaction rate by nZVI activated S2O82- was 1.11 x 10-4 M L-1 min-1 compared to an initial reaction rate of 6.25 x 10-5 M L-1 min-1, 5.18 x 10-6 M L-1 min-1, and 1.8 x 10-7 M L-1 min-1 for Fe2+ activated S2O82-, granular-ZVI activated S2O82-, and non-activated S2O82-, respectively. However, the surfaces of nZVI particles were passivated quickly following exposure to S2O82-, causing the reaction rate to reduce to a magnitude representative of an un-activated S2O82- system. An iron-sulfate (FeSO4) complex was formed on the surfaces of the nZVI particles following exposure to S2O82- compared to the iron oxyhydroxide (FeOOH) layer that was present on fresh nZVI surfaces. BZVNs showed better treatment effectiveness than nZVI particles as activators for H2O2, S2O82-, and HSO5-. For example, the TCE reaction rate constant for nano-Ag-Fe0 activated H2O2 was 9 to 18 fold higher than that for nZVI activated H2O2. Of the nine different BZVNs investigated as activators, the greatest TCE degradation was achieved by nano-Pd-Fe0 and nano-Zn-Fe0 activated S2O82- system, nano-Co-Fe0 activated HSO5- system, and nano-Ag-Fe0 activated H2O2 system. For all of these systems, an increase in the dosage of nanoparticles and peroxygens increased TCE degradation. The activated H2O2 system showed a lower TCE degradation rate compared to either the activated S2O82- or the activated HSO5- systems, suggesting that a bridged group complex is formed between the activators and H2O2. The dissolved TCE concentration remaining in the soil slurry batch systems after using the nano-Pd-Fe0 activated S2O82- system was two to three fold higher than that in an aqueous batch system. Furthermore, for five different aquifer materials used, the higher mass of aquifer materials the lower the TCE degradation, indicating that the aquifer materials compete with a target organic compound in the presence of activated S2O82-. A linear relationship was observed between the organic carbon (OC) content and the initial TCE decomposition rate. Although there is no direct evidence of the effect of OC on the treatment system, it is suggested that the OC may result in scavenging the generated free radicals or by directly consuming persulfate. In the one-dimensional physical model systems, bimetallic nanoparticles were mobile in a non-geological porous medium and relatively immobile in a geological porous medium. In the non-geological porous medium, we found that adding a second metal (e.g., Pd) to nano-Fe0 particles significantly improved their functionality and performance (e.g., mobility and suspension). For example, the results from mobility experiments using columns packed with glass beads showed that the effluent iron concentration was <6 % of the influent iron concentration for the nano-Fe0 particles, while it was ~100 % for the nano-Pd-Fe0 particles. In the geological porous medium, based on visual inspection, nano-Pd-Fe0 particles could not travel more than a few centimeters into columns packed with CFB Borden sand, and no iron was detected in the effluent. To overcome the delivery issue in porous media, nano-Pd-Fe0 particles were injected to create a zone of activation to activate S2O82- for the treatment of TCE source zone. However, we found that the TCE mass destruction was only 9 % higher in the nano-Pd-Fe0 activated S2O82- system compared to the non-activated S2O82- system as revealed by the effluent chloride concentration. In addition, the activation zone composed of nano-Pd-Fe0 particles was rapidly deactivated after exposure to persulfate as visually observed by color change, indicating that the longevity of the activation zone is limited. This research effort provides a contribution to the field of ISCO by evaluating the potential utility and applicability of a new class of activators for some common peroxygens.

Functionalized silica materials are synthesized for various environmental applications. The overall objective is functionalization with sulfur-containing moieties for mercury sorption and as a platform for nanoparticle synthesis. The first objective is quantifying this functionalization for various silica platforms. The second objective is development of effective mercury sorbents, for both aqueous mercury and elemental mercury vapor. Third, those sorbents are incorporated into mixed matrix membranes (MMM) for aqueous mercury sorption. Fourth, functionalized silica materials are developed as platforms for the synthesis of reactive metal nanoparticles (NP) for the degradation of trichloroethylene. Thiol-functionalized silica is used as a sorbent for aqueous mercury, and a novel functionalized material (thiol-functionalized silica shell surrounding a carbon core) has been developed for this application. Total capacity and kinetics of aqueous mercury sorption were determined. The silica-coated carbon was functionalized with thiol and sulfonate moieties for regeneration under mild conditions. Finally, the sorbent particles were incorporated into polysulfone to form a mixed matrix membrane (MMM) for toxic metal capture under convective-flow conditions. High loadings (up to 50% particles, base particles of ~80 nm) were achieved in the MMM. The particles are well-dispersed which can lower mass transfer resistance to the sorption sites. The MMM also imparts several practical advantages such as ease of sorbent handling. Silica functionalized with tetrasulfide silane is used for mercury vapor sorption. Sorption kinetics and dynamic capacity depend upon pore structures of the functionalized material. The particles are thermally stable and exhibit a glass transition in the tetrasulfide silane coating, with high total sorption capacity achieved by addition of copper sulfate. Temperature effects on mercury sorption indicate a chemisorptive mechanism. Silica particles functionalized with sulfonate moieties were used as a platform for the synthesis of dispersed iron nanoparticles. These NP are applied for degradation of trichloroethylene (TCE), a persistent, toxic, and widespread pollutant. The particles were stabilized against agglomeration. Natural product reducing agents, such as ascorbic acid, adsorb to the particle surface and can protect against oxidation. These particles were demonstrated for the reductive as well as oxidative degradation of TCE.

[Truncated abstract] Iron is essential to most biological systems. Under pathological conditions affecting the iron metabolic pathway, iron can be deposited in the tissue in various forms. The work presented in this thesis has exploited the relationship between the magnetic and the chemical properties of tissue iron deposits to further understanding of two major pathologies, the haemoglobinopathies termed thalassaemias and the malaria parasite Plasmodium falciparum, both amongst the most common health concerns in tropical countries. The iron-specific magnetic susceptibilities ¿Fe for spleen tissue samples from 7 transfusion dependent ß-thalassaemia (ß-thal) patients and 11 non-transfusion dependent ß-thalassaemia/Haemoglobin E (ß/E) patients were measured at 37°C. Both groups of patients were iron loaded with no significant difference in the distribution of spleen iron concentrations between the two groups. There was a significant difference between the mean ¿Fe of the spleen tissue from each group. The ß/E patients had a higher mean (± standard deviation) spleen ¿Fe (1.55 ± 0.23 × 10-6 m3.kgFe -1) than the ß-thal patients (1.16 ± 0.25 × 10-6 m3.kgFe -1). Correlations were observed between ¿Fe of the spleen tissue and the fraction of magnetic hyperfine split sextet in the 57Fe Mössbauer spectra of the tissues at 78 K (Spearman rank order correlation ¿ = -0.54, p = 0.03) and between ¿Fe of the spleen tissue and the fraction of doublet in the spectra at 5 K (¿ = 0.58, p = 0.02) indicating that ¿Fe of the spleen tissue is related to the chemical speciation of the iron 2 deposits in the tissue. The biological variability of the iron-specific magnetic susceptibility of the tissue iron examined would contribute a random uncertainty of 19% to magnetic susceptibility based non-invasive measurements of tissue iron concentration. ... Magnetic susceptibility measurements were also performed on malaria parasitised red blood cells. In vitro cultures of P. falciparum were magnetically enriched up to 61-fold using high field gradient magnetic separation columns, and the magnetic susceptibility of cell contents was directly measured. Forms of haem iron were quantified spectroscopically. Further fractionations were performed such that, by controlling the fluid velocity through the column, cells with more than a critical amount of paramagnetic 3 iron were preferentially extracted. A chloroquine-sensitive (CQS) laboratory strain of parasites converted approximately 60% of host cell haem iron to haemozoin and this product was the primary source of the increase in cell magnetic susceptibility. The volumetric magnetic susceptibility of the magnetically enriched cells was found to be 0.15 ± 0.03 × 10-7 relative to the suspension medium, accounting for the enrichment of mature parasites. Comparisons of fractionation samples of two pairs of CQS and chloroquine resistant (CQR) strains showed enrichment of mature parasites was significantly greater in the CQS than the CQR strains. The results suggest the possibility of using magnetic separation columns in identifying CQR strains of P. falciparum, potentially in a diagnostic or research setting. The study also underlines the need to identify and quantify the forms of iron in CQR and CQS parasite strains as the fate of haem iron will have implications in understanding the mechanisms of chloroquine resistance.

abstract: Biofuel from microbial biomass is a viable alternative to current energy production practices that could mitigate greenhouse gas levels and reduce dependency on fossil fuels. Sustainable production of microbial biomass requires efficient utilization of nutrients like phosphorus (P). P is a limited resource which is vital for global food security. This paper seeks to understand the fate of P through biofuel production and proposes a proof-of-concept process to recover P from microbial biomass. The photosynthetic cyanobacterium Synechocystis sp. PCC 6803 is found to contain 1.4% P by dry weight. After the crude lipids are extracted for biofuel processing, 92% of the intercellular P is found within the residual biomass. Most intercellular P is associated with nucleic acids which remain within the cell after lipids are extracted. Phospholipids comprise a small percentage of cellular P. A wet chemical advanced oxidation process of adding 30% hydrogen peroxide followed by 10 min of microwave heating converts 92% of the total cellular P from organic-P and polyphosphate into orthophosphate. P was then isolated and concentrated from the complex digested matrix by use of resins. An anion exchange resin impregnated with iron nanoparticles demonstrates high affinity for P by sorbing 98% of the influent P through 20 bed volumes, but only was able to release 23% of it when regenerated. A strong base anion exchange resin sorbed 87% of the influent P through 20 bed volumes then released 50% of it upon regeneration. The overall P recovery process was able to recover 48% of the starting intercellular P into a pure and concentrated nutrient solution available for reuse. Further optimization of elution could improve P recovery, but this provides a proof-of-concept for converting residual biomass after lipid extraction to a beneficial P source. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2012

Les nanoparticules d'oxyde de fer sont utilisées dans plusieurs domaines notamment en Biomédecine comme agents théranostiques en Cancérologie et aussi comme agents de contraste en Imagerie par Résonance Magnétique. Avec l'augmentation de la production et de l'utilisation de ces NPs de fer, il y a une évidente augmentation de l'exposition humaine et environnementale à ces NPs, et qui peut présenter un risque. Le sujet de ma thèse porte sur l'étude de l’impact physiopathologique et de la toxicité des nanoparticules de fer (NPs de fer) en utilisant un modèle cellulaire de neuroblastome et un modèle d'étude animal, le rat Wistar. L’objectif des travaux de recherche de la partie in vitro est d’évaluer les effets cytotoxiques et génotoxiques ainsi que les effets sur l’expression des protéines cellulaires suite à l’exposition des cellules SH-SY5Y à des concentrations croissantes des NPs de fer. Nous avons montré que les NPs de fer induisent des perturbations cellulaires d’une manière dépendante de la taille et de la concentration. L'analyse protéomique suivie par l'annotation des gènes avec l’ontologie et l'analyse des voies de signalisation a mis en évidence les effets des NPs de fer sur le cytosquelette, l'apoptose et le développement du cancer. Les objectifs de nos travaux de recherche réalisés in vivo consistent à étudier les effets physiopathologiques des NPs de fer administrées par trois voies différentes, intraveineuse, intranasale et orale, à savoir leur impact sur le comportement émotionnel et cognitif ainsi que sur l’homéostasie des neurotransmetteurs et des éléments traces. Les résultats ont montré que les NPs de fer n’induisent pas de modification concernant l’anxiété, la locomotion, l’apprentissage et la mémoire chez le rat quelle que soit la voie d’administration. Cependant, ces NPs provoquent une perturbation des niveaux des catécholamines et des éléments traces au niveau cérébral. Les effets les plus marqués ont été observés suite à l’instillation intranasale des NPs et se manifestent par une diminution de taux du fer sérique, la thrombocytose et la présence des foyers inflammatoires au niveau hépatique. L’analyse comparative des trois voies d’administration a montré que la voie intraveineuse est la moins toxique. Enfin, l’étude protéomique des protéomes du cerveau, du foie et du poumon a permis d’évaluer la toxicité des NPs de fer au niveau protéique et moléculaire. Les résultats obtenus présentent un support important pour l’estimation et la compréhension des effets potentiellement adverses de ces NPs qui présentent une certaine toxicité non négligeable de point de vue moléculaire et physiopathologique. Ainsi, leur utilisation dans le domaine biomédicale doit être prise avec beaucoup de précaution pour éviter au maximum tout risque lié à leur exposition afin d’améliorer leur biocompatibilité et ainsi augmenter leurs avantages. / Iron Oxide Nanoparticles (IONPs) are used in several fields notably in Biomedicine as theranostic agents in Oncology and also as contrast agents in Magnetic Resonance Imaging. With the increase in the production and use of IONPs, there is a clear increase in human and environmental exposure to these NPs, which may pose a risk. The subject of my thesis is the study of the physiopathological impact and toxicity of iron oxide nanoparticles using a cell model of neuroblastoma and an animal study model, the Wistar rat. The aim of the research work of the in vitro part is to evaluate the cytotoxic and genotoxic effects as well as the effects on the expression of cellular proteins following the exposure of SH-SY5Y cells to increasing concentrations of iron NPs. We have shown that iron NPs induce cellular perturbations in a size and concentration dependent manner. Proteomic analysis followed by ontological gene annotation and signaling pathway analysis revealed the effects of IONPs on cytoskeleton, apoptosis and cancer development. The aims of our research carried out in vivo are to investigate the pathophysiological effects of iron NPs administered by three different routes, intravenous, intranasal and oral, also their impact on emotional and cognitive behavior as well as neurotransmitter and trace element homeostasis. The results showed that IONPs do not induce any changes in anxiety, locomotion, learning and memory in rats regardless of the administration route. However, these NPs cause a disruption of catecholamine and trace element levels in the brain. The most marked effects have been observed following intranasal instillation of NPs and are manifested by a decrease in serum iron levels, thrombocytosis and the presence of inflammatory foci in the liver. The comparative analysis of the three routes of administration showed that the intravenous route is the least toxic. Finally, the proteomic study of the proteomes of the brain, liver and lung has made it possible to evaluate the toxicity of the NPs of iron at the protein and molecular level. The obtained results provide an important support for the estimation and understanding of potentially adverse effects of these NPs, which have a certain toxicity that is not negligible from a molecular and physiopathological point of view. Thus, great care must be taken regarding their use in the biomedical field to minimize any risk related to IONP exposure in order to improve their biocompatibility and thus increase their benefits.

This thesis focuses on the synthesis and applications of nanoscale zero valent iron (nZVI) in the environmental remediation of contaminants. The polyvalent characteristics of this nanomaterial are evaluated in this work with the study of its application in a wide range of contaminants: heavy metals and pesticides in water medium, and malodorous sulfur compounds present in air streams. Moreover, a novel method of synthesis of encapsulated nZVI from a waste material is presented, which meets the principles of green chemistry and at the same time represents a low-cost method of obtaining nZVI with improved characteristics. Chapter 1 describes the current state of the topics that will be discussed in the rest of the thesis. Specifically, the different mechanisms of contaminant remediation by nZVI are discussed, a summary of the current synthesis methods is presented and the principal modifications of nZVI to improve its characteristics are described. Finally, the limitations of the current techniques are assessed, which will be the starting point of the thesis. In Chapter 2, the application of nZVI to heavy metal removal during long time periods is explored. The contaminants studied are Zn, Cd, Ni, Cu and Cr, which are the most common heavy metals found in ground and wastewater. A delivery-effect of the heavy metal ions that had already been attached to nZVI surface is observed after long reaction times, which is a consequence of the nZVI aging and oxidation. The conditions that influence the delivery-effect are assessed and possible solutions to this detected problem are presented. In Chapter 3, nZVI is applied to the removal of sulfur-based odorous compounds in air streams. The compounds studied are hydrogen sulfide and dimethyl disulfide (DMDS), which are commonly found in wastewater treatment plants. Both nZVI loading and pH are varied to assess their influence on the process. Bimetallic nanoscale particles of Cu/Fe, Ni/Fe and Pd/Fe are synthesized in order to improve the DMDS abatement by the nZVI. The advantages of this new method for odor removal are discussed at the look of the experimental results. Lastly, a pilot scale test was performed in a wastewater treatment plant in order to test the effectiveness of the nZVI in a real application. The nZVI were applied in a scrubber to eliminate the sulfurous compounds from the pre-treatment area of the wastewater treatment plant. Chapter 4 deals with the application of nZVI to the oxidation of non-biodegradable pollutants by the Fenton reaction. Specifically, the effect of pH on the degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is studied. The advantages of using nZVI as a Fenton reagent compared to homogeneous Fenton are described. Furthermore, the addition of UV-light to the process is investigated. Finally, the main degradation intermediates of the reaction are identified and a degradation mechanism is accordingly proposed. In Chapter 5, the presence of polychlorinated dioxins and furans (PCDD/Fs) in the nZVI surface is addressed. Studies have shown that nZVI enhances the formation of such chlorinated compounds during thermal processes, but it is unclear which the origin of the compounds is. It has been suggested that nZVI could possess impurities such as PCDD/Fs in its surface. Therefore, the concentration of PCDD/Fs in both commercial and laboratory-synthesized nanoparticles is analyzed. PCDD/Fs pattern and WHO-TEQ concentrations are also obtained. As an outcome of the results obtained in this chapter, a recommendation for preventing the PCDD/Fs presence in nZVI is given. Chapter 6 is dedicated to the synthesis of carbon-encapsulated nanoparticles using hydrothermal carbonization (HTC) of an agricultural waste, particularly, olive mill wastewater (OMW). This novel method, in addition to meet the green chemistry principles, makes profit of the high polyphenol content of OMW to maximize the fraction of incorporated iron into the nZVI. Moreover, the carbon layer surrounding the nZVI protects it against oxidation and avoids its aggregation. Several HTC conditions are explored to study their implications in the characteristics of the material obtained. A deep characterization of the encapsulated nZVI is also presented in this chapter. In Chapter 7, the applications of the encapsulated nZVI synthesized in Chapter 6 are explored and compared for the same contaminants that have been studied in the previous chapters. Then, the advantages of encapsulated nZVI in comparison with common nZVI are discussed at the end of the chapter, and an estimation of the synthesis costs with this method is addressed. Lastly, in Chapter 8, the main conclusions of the thesis are summarized and suggestions for future work are presented.