In Southern Africa, historic mining and mineral processing of base metal deposits have almost exclusively focussed on the extraction of major metals, leading to the loss of remaining valuable raw materials into tailings dumps and waste rock piles. At the Namib Pb-Zn mine (Erongo Region, Namibia), historic base metal tailings deposits are present as unreclaimed exposed waste piles. The tailings comprise silt- (fraction A: d50 = 25 to 48 μm) to sand-sized (fraction B: d50 = 86 to 185 μm; fraction C: d5o = 210 to 230 μm) material and contain major concentrations of base metals (Pb av. 1.15 mass%, Zn av. 3.20 mass%), S (av. 9.95 mass%), as well as lower values of other metals (Cu av. 490 μg/g, Cd av. 133 μg/g, Ag av. 22 μg/g), and critical elements like Sb (av. 14.7 μg/g) and In (14.3 μg/g). Former mineral processing only targeted the extraction of galena and sphalerite. As a consequence, qualitative mineralogical composition of the tailings is similar to that of the primary ore. Ca-Fe-Mg(-Mn) carbonates, quartz, micas, chlorite, minor graphite, magnetite, and rare parisite relate to the former host rock and gangue matrix, whereas Fe-rich sphalerite, galena, magnetite, pyrite with minor pyrrhotite, rare arsenopyrite, marcasite, cassiterite, and accessory scheelite are original constituents of the primary ore. Reprocessing of such a material would be challenging, but a mixed Pb-Zn concentrate enriched in Cd and Ag might be obtained. In future, possible reprocessing of Namib tailings and associated disposal of wastes into an appropriately designed repository would not only generate valuable metal commodities, but such activities would also eliminate a major metal pollution source from the local environment.

SYNOPSIS An oolitic iron ore from Gara Djebilet, Algeria was characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrosopy and the phosphorus distribution between various phases studied. Two ore types were identified - a haematite-dominated, oolitic type and a more massive, magnetite-dominated type. The haematite-dominated ore had a higher phosphorus content, up to 0.6% in the iron oxide minerals, than the magnetite-dominated type (0.3% P). Owing to the very fine-grained texture of the gangue minerals, reducing the phosphorus content to levels suitable for steelmaking (below 0.05% P) by conventiobal means would entail an energy-intensive process with a high carbon footprint. Preliminary leaching test work using a sulphurous geothermal water as lixiviant, assisted by solar thermal acceleration, gave very promising results, removing 0.13% of the residual P (or 21.7% removal of total P) from the high-phosphorus oolitic ore.

ABSTRACT Magnetic experiments have provided insight into the preservation of magnetite in sediments of the Inner Sea of the Maldives during early diagenesis. In this study, we present high-resolution remanence data on the upper 15 meters of the sedimentary record and a detailed magnetic characterization of discrete samples from the top 5.5 meters of the International Ocean Discovery Program (IODP) Site U1471 record. Based on magnetic experiments, it can be concluded that magnetite is rapidly reduced, with a large decrease in natural remanent magnetization (NRM) related to destruction of primary NRM below the upper two meters of the sedimentary record. In thermomagnetic experiments, the appearance of a greigite signal at 3.06 meters below sea floor (mbsf) suggests that current diagenesis could imprint nearly 100 kry of error on the chronology based on magnetostratigraphy. Furthermore, based on X-ray fluorescence data, it can be concluded that magnetite reduction did not affect the Fe record. study highresolution high resolution 1 55 5 5. IODP (IODP U U147 reduced (NRM 306 3 06 3.0 mbsf (mbsf 10 magnetostratigraphy Furthermore Xray X ray U14 30 0 3. U1

In recent years, various methods for surface functionalization of magnetite nanoparticles with emerging modifications have been explored and reported. Green nano-chemistry aims to synthesize nanomaterials using bio-based resources, providing new materials for biological and environmental applications. Surface modification of magnetite nanoparticles using phytochemicals extracted from plants is a fundamental principle of green synthesis routes. Agricultural waste from different crops, such as plantain pseudostem, is of particular interest as a renewable resource due to its abundant availability, low toxicity, and economic feasibility. In this study, the juice extracted from plantain pseudostem was utilized for the phytofunctionalization of magnetite nanoparticles. Characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and fourier-transform infrared spectroscopy (FTIR) confirmed the nanometric dimensions of the composite (size range of 12.6 ± 3.17 nm) and established its organic-inorganic nature. The superparamagnetic properties of the composite were also demonstrated. Moreover, the potential application of this nanohybrid in bioremediation for the immobilization of cadmium(II) and lead(II) showed promising results, highlighting its efficacy in managing water pollutants. years reported nanochemistry nano chemistry biobased bio based resources applications routes crops availability toxicity feasibility study TEM, TEM , (TEM) SEM, SEM (SEM) TGA, TGA (TGA) fouriertransform fourier transform FTIR (FTIR size 126 12 6 12. 317 3 17 3.1 nm organicinorganic organic inorganic nature demonstrated Moreover cadmiumII cadmium II cadmium(II leadII lead lead(II results pollutants (TEM (SEM (TGA 1 31 3.

Nanocomposites of magnetite anchored on reduced graphene oxide with different magnetite:reduced graphene oxide mass ratios were synthesized and evaluated in indigo carmine photo Fenton discoloration. All nanocomposites are magnetic and showed comparable amounts of magnetite and hematite with a higher level of hematite for low iron contents. The highest value of 63.6 emu g−1 was obtained for the nanocomposite with the highest magnetite content. The nanocomposites presented high dispersion of iron oxide particles, at about 12 nm on reduced graphene oxide surface sheets. The samples also showed bandgap energies below that found for bulk magnetite, showing an important effect of reduced graphene oxide. The nanocomposite with an iron nitrate precursors mass ratio of 17:1 showed the best performance (99.7% of indigo carmine discoloration (2.1 × 10−5 mol L−1) at 30 min of reaction, hydrogen peroxide (2.3 × 10−1 mol L−1), and a catalyst dosage of 0.67 g L−1). Reusability tests were performed, and this nanocomposite was shown to be active for at least three recycles. X-ray photoelectron spectrum of Fe2p3/2 showed that the FeIII/FeII ratio was maintained even after three recycles (4 runs), meaning that reduced graphene oxide is responsible for stabilizing magnetite particles, thus maintaining its photocatalytic activity. magnetitereduced contents 636 63 6 63. g1 1 g− content particles sheets 171 17 17: 99.7% 997 99 7 (99.7 2.1 21 2 (2. 105 10 5 10− L−1 L1 L 3 reaction 2.3 23 101 L−1, , 067 0 67 0.6 L−1. . performed Xray X ray Fe2p32 Fep Fe2p3 Fe p Fe2p3/ FeIIIFeII FeIII FeII 4 ( runs, runs runs) activity 99.7 9 (99. 2. (2 L− 06 0. Fe2p 99. (99 (9

Abstract The transport capacity of the slurry pipelines is related to the internal roughness of the pipe. Thus, the application of corrosion protection methods is of fundamental importance, both in the operational phase and in times of temporary shutdown. In addition, corrosion also affects the service life of the duct. The studied pipeline was hibernated with nitrogen using the ABNT NBR 15280-2 standard as a reference and remained hibernated for 3.5 years. Chemical, mineralogical, and microstructural analyses were carried out on samples of materials removed from the pipeline interior during the hibernation period. The most striking phase found was magnetite, with botrioidal morphology, formed by the oxidation of steel in the pipeline. After reactivation, the pipeline was inspected by smart pigs with ultrasound and MFL technologies. It was found that the corroded regions are more concentrated in the initial kilometers of the sections, where important depths of corrosion were also observed, as well as higher rates of corrosion and erosion, which show the influence of the operational phase in the development of the pipeline corrosive process and wear. Thus, the application of the nitrogen hibernation process in long-distance pipelines proved to be feasible for long periods of time. However, improvements are suggested in this article to make the process more robust. pipe Thus importance shutdown addition duct 152802 15280 2 15280- 35 3 5 3. years Chemical mineralogical period magnetite morphology reactivation technologies sections observed erosion wear longdistance distance time However robust 1528 152 15 1

The synthesis of oxides using plant extracts as precursors has attracted attention as it is an economical, efficient, and ecological route. Euterpe oleracea Mart, available in the Legal Amazon, has great potential due to its composition, rich secondary metabolites. Therefore, this work aimed to investigate the potential of aqueous açaí leaf extract as precursors in synthesizing FexOy-type oxides. The synthesis was developed in two stages to obtain the hematite phases (step 1) and the magnetite phase (step 2). The effect of pH on phase formation and structure was evaluated in step 1. Then, the material was obtained in step 2 by precipitation with pH adjustment. The powders were characterized by thermal analysis, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The results showed that pH played a significant role in the thermal behavior, crystallite sizes, and structural parameters of hematite, with neutral or acidic pH being more attractive for obtaining crystallites between 21 and 24 nm. Magnetite with 21.51 nm crystallites was precipitated, indicating possible capping of the Fe3O4 particles and preserving their magnetic characteristics. economical efficient route Mart Amazon composition metabolites Therefore FexOytype FexOy type 1 2. . 2) Then adjustment analysis Xray X ray diffraction spectroscopy microscopy behavior sizes 2151 51 21.5 precipitated FeO Fe O Fe3O characteristics 215 5 21.

Lipases have been used in industrial processes as biocatalysts for transesterification reactions. The synergism between enzymes and magnetic properties may be reached by using magnetic nanoparticles (MNPs) as support to immobilize them in aggregate structures, denominated by magnetic crosslinked enzyme aggregates (MCLEA). One of the advantages of such supports is the possibility of using magnetic separation for enzyme recovery, reducing costs and allowing reuse in continuous systems. Here, porcine pancreatic lipase (PPL) was immobilized onto functionalized magnetite support (Fe3O4-APTS) with a protein binding efficiency of 78.84%. Physical and chemical properties of the nanoparticles and immobilized lipase were characterized by X-ray diffraction (XDR), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential, vibrating sample magnetometer measurements (VSM), and 57Fe Mössbauer spectroscopy. The immobilized lipase additionally exhibited improved stability across wide pH and temperature ranges compared with free lipase. The immobilized derivate also attained good reusability, maintaining 61.37% of its initial activity after 6 reaction cycles. Through magnetic behavior and also because of its surface modification to crosslinking the enzyme, the MCLEA produced in this work has enhanced the biocatalytic activities of PPL. reactions MNPs (MNPs structures MCLEA. . (MCLEA) recovery systems Here PPL (PPL Fe3O4APTS FeOAPTS Fe3O4 APTS Fe O (Fe3O4-APTS 7884 78 84 78.84% Xray X ray XDR, XDR , (XDR) TEM, TEM (TEM) FTIR, FTIR (FTIR) DLS, DLS (DLS) potential VSM, VSM (VSM) reusability 6137 61 37 61.37 cycles (MCLEA FeO Fe3O 788 7 8 78.84 (XDR (TEM (FTIR (DLS (VSM 613 3 61.3 78.8 61. 78.

Resumo Nanopartículas são consideradas opções viáveis no tratamento do câncer. Este estudo foi conduzido para investigar o efeito de nanopartículas de magnetita (MNPs) e núcleo de folato de magnetita (MFCS) em culturas de células leucêmicas e de hepatocarcinoma, bem como seu efeito no modelo animal de leucemia mielocítica aguda (LMA). Através do atual estudo, nanopartículas foram sintetizadas, caracterizadas por várias técnicas, e suas propriedades foram estudadas para confirmar sua nanoestrutura. No estudo in vivo, as nanopartículas foram avaliadas para inspecionar sua atividade citotóxica contra células SNU-182 (carcinoma hepatocelular humano), K562 (leucemia humana) e THLE2 (fígado epitelial humano normal) por meio do teste MTT. A expressão das proteínas sinalizadoras apoptóticas Bcl-2 e Caspase-3 foram inspecionadas através do método RT-PCR. Um efeito citotóxico de MNPs e MFCS foi detectado em culturas de células anteriores. Além disso, a apoptose foi identificada por meio de regulação positiva significativa da Caspase-3, com regulação negativa de Bcl-2. No estudo in vitro, a AML foi induzida em ratos por N-metil-N-nitrosoureia seguida por tratamento oral com MNPS e MFCS. Índices bioquímicos como aspartato e alanina aminotransferases e atividades de lactato desidrogenase, ácido úrico, hemograma completo e Beta-2-microglubulina foram avaliados no soro. A imunofenotipagem para detecção de CD34 e CD38 foi realizada. Fígado, rim e medula óssea foram examinados microscopicamente. A metilação do promotor Bcl-2 e os níveis de mRNA foram examinados. Embora tanto os MNPs quanto os MFCS representem uma melhora nos parâmetros bioquímicos, o MFCS os aliviou em direção ao controle normal. A atividade anticâncer de MNPs e MFCS foi aprovada especialmente para AML. Sempre, a administração de MFCS foi mais eficaz do que MNPs. O presente trabalho é um dos poucos estudos que utilizou o MFCS como agente anticâncer.

Abstract Nanoparticles are considered viable options in the treatment of cancer. This study was conducted to investigate the effect of magnetite nanoparticles (MNPs) and magnetite folate core shell (MFCS) on leukemic and hepatocarcinoma cell cultures as well as their effect on the animal model of acute myelocytic leukemia (AML). Through current study nanoparticles were synthesized, characterized by various techniques, and their properties were studied to confirm their nanostructure. Invivo study, nanoparticles were evaluated to inspect their cytotoxic activity against SNU-182 (human hepatocellular carcinoma), K562 (human leukemia), and THLE2 (human normal epithelial liver) cells via MTT test. Apoptotic signaling proteins Bcl-2 and Caspase-3 expression were inspected through RT-PCR method. A cytotoxic effect of MNPs and MFCS was detected in previous cell cultures. Moreover, the apoptosis was identified through significant up-regulation of caspase-3, with Bcl-2 down-regulation. Invitro study, AML was induced in rats by N-methyl-N-nitrosourea followed by oral treatment with MNPS and MFCS. Biochemical indices such as aspartate and alanine amino transferases, and lactate dehydrogenase activities, uric acid, complete blood count, and Beta -2-microglubulin were assessed in serum. Immunophenotyping for CD34 and CD38 detection was performed. Liver, kidney, and bone marrow were microscopically examined. Bcl-2 promoter methylation, and mRNA levels were examined. Although, both MNPs and MFCS depict amelioration in biochemical parameters, MFCS alleviated them toward normal control. Anticancer activity of MNPs and MFCS was approved especially for AML. Whenever, administration of MFCS was more effective than MNPs. The present work is one of few studies used MFCS as anticancer agent.

Abstract Jacobsite is a relatively rare mineral of composition MnFe2O4, found in Urandi (Bahia State) in Brazil. It is also a common species in the deep-sea manganese nodules, attracting the interest of many mineral-extracting companies. Because of its spinel constitution similar to magnetite, Jacobsite is commonly called a manganese-ferrite. However, the manganese/iron content may vary substantially according to its origin, demanding specific studies in each case. The Jacobsite mineral inspired our laboratory synthesis of the analogous manganese ferrite nanoparticles. The direct synthesis by the coprecipitation method has not been successful; however, it can be carried in the presence of citrate ions, yielding strongly magnetic nanoparticles, with a maximum magnetization of 45.6 emu.g1. Although they were structurally identical to Jacobsite, the mineral from Bahia exhibited a rather weak magnetism, because it involves a ferrimagnetic coupling. For this reason, the synthetic method seems to provide a better way of obtaining strongly magnetic manganese ferrites. These magnetic nanoparticles have been investigated in detail, including their interaction with diatoms, providing interesting magnetic bio-silicate carriers in drug delivery. MnFe2O4 MnFeO MnFe O State Brazil deepsea deep sea nodules mineralextracting extracting companies magnetite manganeseferrite. manganeseferrite ferrite. manganese-ferrite However manganeseiron iron origin case successful however ions 456 45 6 45. emug1 emug emu g1 g emu.g1 magnetism coupling reason ferrites detail diatoms biosilicate bio silicate delivery MnFe2O 4 emu.g

Abstract Iron oxide nanoparticles (FeO-NPs) are widely used in scientific and technological fields. Environmental concerns have been raised about residual FeO-NPs levels as their toxicity and bioaccumulative potential are not well understood. Oreochromis niloticus were exposed to nanoparticles of γ-Fe2O3 and Fe3O4. Micro-CT 3D image and grayscale graphic assessments revealed the accumulation of radiopaque material in the digestive tract of fish exposed to FeO-NPs. Histological analysis showed the presence of such NPs in the hepatopancreas, gills, kidneys, and muscles. No genotoxicity occurred, through micronucleus test and comet assay in peripheral erythrocytes. Body clearance was confirmed by iron-content reduction in organisms exposed to FeO-NPs after recovery period. No tissue injuries were observed in the exposed animals which may be attributed to the absence or low toxicity of iron oxide nanoparticles under the study conditions. O. niloticus showed tolerance to sublethal exposures to FeO-NPs. FeONPs FeO (FeO-NPs fields understood γFe2O3 γFeO γ Fe2O3 Fe O γ-Fe2O Fe3O4 MicroCT Micro CT D FeONPs. NPs. hepatopancreas gills kidneys muscles occurred erythrocytes ironcontent content period conditions γFe γFe2O Fe2O Fe3O

As nanopartículas (NPs) à base de óxido de ferro, como magnetita e maguemita, têm grande destaque em diversas áreas da ciência, inclusive na medicina. Há décadas, elas são usadas na reposição de ferro para pacientes com anemia, como agentes de contraste em ressonância magnética (MRI – “Magnetic Resonance Imaging”), na entrega de agentes terapêuticos mediada ou não por gradiente de campo magnético, em terapias térmicas foto e magnetoestimuladas, entre outras. Neste artigo, apresentamos suas propriedades magnéticas. Discutimos de forma breve seu ordenamento ferrimagnético, a importância da anisotropia magnética e sua relação com a histerese magnética (modelo de Stoner-Wohlfarth) e o regime superparamagnético. As diferenças entre superparamagnetismo e paramagnetismo são enfatizadas, além da importância da estabilidade coloidal dessas nanoestruturas para aplicações biomédicas. Finalmente, diversas aplicações biomédicas são discutidas, entre elas hipertermia magnética, terapia fototérmica, imunoterapia e uma nova técnica de imagem com potencial clínico, conhecida como “Magnetic Particle Imaging” (MPI). NPs (NPs maguemita ciência medicina décadas anemia MRI Magnetic Imaging, Imaging , Imaging”) magnético magnetoestimuladas outras artigo magnéticas ferrimagnético modelo StonerWohlfarth Stoner Wohlfarth Stoner-Wohlfarth superparamagnético enfatizadas Finalmente discutidas fototérmica clínico MPI. MPI . (MPI) (MPI

Iron oxide-based nanoparticles (NPs), such as magnetite and maghemite, are highly prominent in various scientific fields, including medicine. For decades, they have been used for iron supplementation in patients with anemia, as contrast agents in magnetic resonance imaging (MRI), in the delivery of therapeutic agents mediated or not by magnetic field gradients, and in photo- and magneto-stimulated thermal therapies, among other applications. In this article, we present their magnetic properties. We briefly discuss their ferrimagnetic ordering, the importance of magnetic anisotropy and its relation to magnetic hysteresis (Stoner-Wohlfarth model), and the superparamagnetic regime. The differences between superparamagnetism and paramagnetism are emphasized, as well as the importance of the colloidal stability of these nanostructures for biomedical applications. Finally, various biomedical applications are discussed, including magnetic hyperthermia, photothermal therapy, immunotherapy, and a new imaging technique with clinical potential known as Magnetic Particle Imaging (MPI). oxidebased oxide based NPs, NPs , (NPs) maghemite fields medicine decades anemia MRI, MRI (MRI) gradients photo magnetostimulated magneto stimulated therapies article properties ordering StonerWohlfarth Stoner Wohlfarth model, model model) regime emphasized Finally discussed hyperthermia therapy immunotherapy MPI. MPI . (MPI) (NPs (MRI (MPI

Abstract In this work, magnetic polymeric microspheres were prepared through the copolymerization of styrene and divinylbenzene in the presence of magnetite synthesized in our laboratory. The effects of magnetite modification with oleic acid, stirring speed, initiator concentration and stabilizer concentration on the particles’ properties were studied. The magnetic microspheres were characterized according to morphology, thermal stability, particle size and distribution, and magnetic properties. The microspheres had spherical shape, micrometric size and superparamagnetic properties. Particle size was mainly affected by stirring speed, while particle size dispersion was strongly affected by initiator and stabilizer concentrations. The saturation magnetization of the microspheres was similar to the values reported in the literature for microspheres with the same content of magnetic material. The modification with oleic acid promoted the incorporation of magnetic material. work laboratory speed particles studied morphology stability distribution shape concentrations material

Abstract Nanocomposites formed of natural-origin iron oxide nanoparticles (magnetite and maghemite, Fe3O4 and γ-Fe2O3, respectively) were processed using the sol-gel process into core-shell structures containing silica and samarium to investigate their potential for applications in cancer treatments combining hyperthermia and brachytherapy. Mössbauer characterization showed that the iron oxides contained 64% magnetite, 18% hematite, 12% maghemite, and exhibit superparamagnetic behavior at room temperature. Transmission electron microscopy determined that the iron oxide particles were smaller than 15 nm, while magnetization was measured at 5 emu/g. Fourier transform infrared indicated the material was formed of Si-O-Si and Fe-O-Si bonds, while X-ray diffraction showed bands of amorphous silica from 5° to 23° and bands of iron oxide phases. X-ray fluorescence indicated 5.17% of incorporated samarium. The nanocomposite suspensions were subjected to an alternating magnetic field and the resulting heat dissipation was measured, falling within the ideal range for hyperthermia applications. Theoretical dosimetric calculation determined significant radioactive activity of 1.68x10-8 MBq.mg-1.Φ -1 after 24h decay time for 153Sm. The characteristics and behavior of these nanocomposites indicate that they may offer promise in applications involving hyperthermia for cancer treatment and a more accessible source for brachytherapy materials. naturalorigin natural origin magnetite maghemite FeO Fe O Fe3O γFe2O3, γFe2O3 γFeO γ Fe2O3, Fe2O3 γ-Fe2O3 respectively solgel sol gel coreshell core shell 64 18 hematite 12 temperature 1 nm emug emu g emu/g SiOSi Si FeOSi bonds Xray X ray 23 phases 517 17 5.17 1.68x108 168x108 x 1.68x10 8 68x10 1.68x10- MBq.mg1.Φ MBqmg1Φ MBqmgΦ MBq.mg 1.Φ MBq mg Φ - h 153Sm Sm materials γFe γFe2O Fe2O γ-Fe2O 6 2 51 5.1 68x108 168x10 1.68x1 68x1 mg1 MBqmg 1Φ 5. 168x1 1.68x 68x 168x

RESUMEN En Ecuador muchos efluentes provenientes de la industria curtiembre presentan altos niveles de Cr (VI) generando gran impacto ambiental por la alta toxicidad del metal; una alternativa para remover este contaminante es mediante agentes adsorbentes como nanopartículas magnéticas. El objetivo de la presente investigación fue sintetizar nanopartículas de magnetita recubiertas de quitosano para la adsorción de cromo hexavalente. El quitosano se obtuvo a partir del exoesqueleto del camarón y las nanopartículas fueron sintetizadas por coprecipitación química y recubiertas con quitosano de manera In-situ. Se verificó la síntesis mediante espectroscopía infrarroja y microscopía electrónica de barrido. La capacidad de adsorción de cromo hexavalente se determinó a partir de experimentos de adsorción variando los parámetros termodinámicos, y la cuantificación del mismo se lo realizó utilizando espectroscopía UV-Visible. De tal manera que se obtuvieron nanopartículas con un diámetro promedio de 31,85 nm y el mayor porcentaje de adsorción fue del 99,70 %, con una capacidad máxima de adsorción de 294,12 mg/g a 60 °C. Demostrando que fue factible la adsorción de cromo hexavalente utilizando nanopartículas de magnetita recubiertas de quitosano con mejor capacidad de adsorción gracias al recubrimiento de quitosano.

ABSTRACT In Ecuador, many effluents from the tanning industry have high levels of Cr (VI), generating great environmental impact due to the high toxicity of the metal. An alternative way to remove this contaminant is through adsorbent agents such as magnetic nanoparticles. The objective of the present investigation was to synthesize chitosan-coated magnetite nanoparticles for hexavalent chromium adsorption. The chitosan was obtained from the exoskeleton of the shrimp, and the nanoparticles were synthesized by chemical coprecipitation and coated with chitosan in an In-situ manner. The synthesis was verified by infrared spectroscopy and scanning electron microscopy. The adsorption capacity of hexavalent chromium was performed from adsorption experiments varying the thermodynamic parameters, and the quantification was carried out using UV-Visible spectroscopy. In such a way that chitosan-coated magnetite nanoparticles with an average diameter of 31.85 nm were obtained and the highest adsorption percentage was 99.70%, with a maximum adsorption capacity of 294.12 mg/g at 60 °C, demonstrating that hexavalent chromium adsorption was feasible using chitosan-coated magnetite nanoparticles with better adsorption capacity thanks to the chitosan coating.