Reusable Fe₃O₄/SBA15 nanocomposite as an efficient photo-Fenton catalyst for the removal of sulfamethoxazole and Orange II

Today, the presence of recalcitrant pollutants in wastewater, such as pharmaceuticals or other organic compounds, is one of the main obstacles to the widespread implementation of water reuse. In this context, the development of innovative processes for their removal becomes necessary to guarantee effluent quality. This work presents the potentiality of magnetic nanoparticles immobilized on SBA-15 mesoporous silica as Fenton and photo-Fenton catalysts under visible light irradiation. The influence of the characteristics of the compounds and nanoparticles on the removal yield was investigated. Once the key aspects of the reaction mechanism were analyzed, to evaluate the feasibility of this process, an azo dye (Orange II) and an antibiotic (sulfamethoxazole) were selected as main target compounds. The concentration of Orange II decreased below the detection limit after two hours of reaction, with mineralization values of 60%. In addition, repeated sequential experiments revealed the recoverability and stability of the nanoparticles in a small-scale reactor. The benchmarking of the obtained results showed a significant improvement of the process using visible light in terms of kinetic performance, comparing the results to the Fenton process conducted at dark. Reusability, yield and easy separation of the catalyst are its main advantages for the industrial application of this processThis research was supported by two projects granted by Spanish Ministry of Science, Innovation and Universities: HP-NANOBIO Project, grant number PID2019-111163RB-I00; CLUSTERCAT Project, grant number MAT2015-67458-P; and Fundación Ramón Areces (Spain), grant number CIVP18A3940.S

Novel synthetic routes of large-pore magnetic mesoporous nanocomposites (SBA-15/Fe3O4) as potential multifunctional theranostic nanodevices

In this paper, novel magnetic silica nanocomposites were prepared by anchoring magnetite nanoparticles onto the outer surface of mesoporous SBA-15 silica; the magnetic nanoparticles were prepared by microemulsion and solvothermal methods, varying the synthesis conditions in order to control the final physicochemical, textural and magnetic properties. The morphology and mesostructure of the materials were characterized by X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), N2 adsorption–desorption, and Transmission and Scanning Electron Microscopy (TEM and SEM). Magnetic silica nanocomposites feature a two-dimensional hexagonal arrangement constituted by a homogeneous pore channel system with diameters between 13 and 18 nm and a Brunauer–Emmett–Teller (BET) surface area higher than 260 m2 g−1. The different morphologies of the samples are given by the presence of diverse magnetic nanoparticle arrangements covalently linked onto the outer surface of the mesoporous silica rods. This confers on them a superparamagnetic behaviour with a magnetic response between 50–80 emu g−1, even though the weight percent of magnetite present in the samples does not exceed 21.7%. In addition, the magnetic nanocomposites exhibit magnetic hyperthermia with moderate Specific Absorption Rate (SAR) valuesThis work was supported in part by MINECO (Spain) and FEDER Funds (projects MAT 2015-67458-P and CTQ2016-79461-R); and the European Commission (PANA project, Call H2020-NMP-2015-two-stage, Grant 686009; and the MADIA project, Call H2020-ICT-2016-1, Grant 732678)S

LED-driven photo-Fenton process for micropollutant removal by nanostructured magnetite anchored in mesoporous silica

The presence of organic micropollutants in water bodies represents a threat to living organisms and ecosystems due to their toxicological effects and recalcitrance in conventional wastewater treatments. In this context, the application of heterogeneous photo-Fenton based on magnetite nanoparticles supported on mesoporous silica (SBA15) is proposed to carry out the non-specific degradation of the model compounds ibuprofen, carbamazepine, hormones, bisphenol A and the dye ProcionRed®. The operating conditions (i.e., pH, catalyst load and hydrogen peroxide concentration) were optimized by Response Surface Methodology (RSM). The paramagnetic properties of the nanocatalysts allowed their repeated use in sequential batch operations with catalyst losses below 1%. The feasibility of the process was demonstrated as removal rates above 90% after twelve accomplished after twelve consecutive cycles. In addition, the contributions of different reactive oxygen species, mainly •OH, were analyzed together with the formation of by-products, achieving total mineralization values of 15% on averageThis research was supported by HP-NANOBIO [PID2019-111163RB-I00] and MAGDEMON [PID2020-112626RB] projects, funded by MCIN/AEI/10.13039/501100011033 and SPOTLIGHT [PDC2021-121540-I00] project, funded by MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR. J.G.-R. thanks MCIN/AEI/10.13039/501100011033 for their FPU predoctoral fellowship [FPU19/00461] and J.J.C. thanks Xunta de Galicia for his postdoctoral fellowship [ED481B-2021/015]. The authors belong to the Galician Competitive Research Groups (GRC) ED431C-2021/16 and ED432C-2021/37, co-funded by FEDER (EU)S

Exploiting the potential of supported magnetic nanomaterials as Fenton-Like catalysts for environmental applications

In recent years, the application of magnetic nanoparticles as alternative catalysts to conventional Fenton processes has been investigated for the removal of emerging pollutants in wastewater. While this type of catalyst reduces the release of iron hydroxides with the treated effluent, it also presents certain disadvantages, such as slower reaction kinetics associated with the availability of iron and mass transfer limitations. To overcome these drawbacks, the functionalization of the nanocatalyst surface through the addition of coatings such as polyacrylic acid (PAA) and their immobilization on a mesoporous silica matrix (SBA15) can be factors that improve the dispersion and stability of the nanoparticles. Under these premises, the performance of the nanoparticle coating and nanoparticle-mesoporous matrix binomials in the degradation of dyes as examples of recalcitrant compounds were evaluated. Based on the outcomes of dye degradation by the different functionalized nanocatalysts and nanocomposites, the nanoparticles embedded in a mesoporous matrix were applied for the removal of estrogens (E1, E2, EE2), accomplishing high removal percentages (above 90%) after the optimization of the operational variables. With the feasibility of their recovery in mind, the nanostructured materials represented a significant advantage as their magnetic character allows their separation for reuse in different successive sequential batch cyclesThis research was funded by HP-NANOBIO Project (PID2019-111163RB-I00) and MAGDEMON Project (PID2020-112626RB) granted by Spanish Ministry of Science and InnovationS

Novel synthetic routes of large-pore magnetic mesoporous nanocomposites (SBA-15/Fe3O4) as potential multifunctional theranostic nanodevices

In this paper, novel magnetic silica nanocomposites were prepared by anchoring magnetite nanoparticles onto the outer surface of mesoporous SBA-15 silica; the magnetic nanoparticles were prepared by microemulsion and solvothermal methods, varying the synthesis conditions in order to control the final physicochemical, textural and magnetic properties. The morphology and mesostructure of the materials were characterized by X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), N2 adsorption-desorption, and Transmission and Scanning Electron Microscopy (TEM and SEM). Magnetic silica nanocomposites feature a two-dimensional hexagonal arrangement constituted by a homogeneous pore channel system with diameters between 13 and 18 nm and a Brunauer-Emmett-Teller (BET) surface area higher than 260 m2 g-1. The different morphologies of the samples are given by the presence of diverse magnetic nanoparticle arrangements covalently linked onto the outer surface of the mesoporous silica rods. This confers on them a superparamagnetic behaviour with a magnetic response between 50-80 emu g-1, even though the weight percent of magnetite present in the samples does not exceed 21.7%. In addition, the magnetic nanocomposites exhibit magnetic hyperthermia with moderate Specific Absorption Rate (SAR) values. © 2017 The Royal Society of Chemistry.This work was supported in part by MINECO (Spain) and FEDER Funds (projects MAT 2015-67458-P and CTQ2016-79461-R); and the European Commission (PANA project, Call H2020-NMP-2015-two-stage, Grant 686009; and the MADIA project, Call H2020-ICT-2016-1, Grant 732678).Peer reviewe

Three-Dimensional Hybrid Mesoporous Scaffolds for Simvastatin Sustained Delivery with in Vitro Cell Compatibility

The development of scaffolds with suitable physicochemical and mechanical properties allowing for the structural regeneration of injured bone and recovery of the natural biological functionality is still a challenge in the tissue engineering field. Nanostructured materials with added theranostic abilities, together with an interconnected hierarchy of pores, offer the possibility to provide a new generation of bone implants. In this work, scaffolds with highly porous and resistant threedimensional structures have been successfully developed by homogeneously embedding mesoporous silica nanostructures in a bioactive matrix of chitosan/κ-carrageenan. Moreover, magnetite (Fe3O4) nanoparticles were also added to the mesoporous scaffold to include additional magnetic functionalities for diagnostic or therapeutic actions. The complete physicochemical characterization shows mesoporous materials with a wide range of interconnected pores, remarkable surface roughness, and large effective surface area, suitable for cell adhesion. In accordance to these properties, a simvastatin loading and release assay showed high loading capacities and sustained release over a long period of time. Together with a suitable resistance against degradation and biocompatible performance assessed by cell viability assays, these scaffolds show interesting features for delivering drugs with activity in bone regeneration processes.This work was supported by the European Commission (PANA project, Call H2020-NMP-2015-two-stage, grant 686009); and the Xunta de Galicia (GPC2017/015), and partially supported by the Consellería de Educacion Program ́ for the Development of Strategic Grouping in Materials AEMAT at the University of Santiago de Compostela under grant no. ED431E2018/08, Xunta de Galicia and Program for the Consolidation of Research Units of Competitive Reference GRC2017, grant no. ED431C 2017/22S

Multifunctional Superparamagnetic Stiff Nanoreservoirs for Blood Brain Barrier Applications

Neurological diseases (Alzheimer’s disease, Parkinson’s disease, and stroke) are becoming a major concern for health systems in developed countries due to the increment of ageing in the population, and many resources are devoted to the development of new therapies and contrast agents for selective imaging. However, the strong isolation of the brain by the brain blood barrier (BBB) prevents not only the crossing of pathogens, but also a large set of beneficial drugs. Therefore, an alternative strategy is arising based on the anchoring to vascular endothelial cells of nanoplatforms working as delivery reservoirs. In this work, novel injectable mesoporous nanorods, wrapped by a fluorescent magnetic nanoparticles envelope, are proposed as biocompatible reservoirs with an extremely high loading capacity, surface versatility, and optimal morphology for enhanced grafting to vessels during their diffusive flow. Wet chemistry techniques allow for the development of mesoporous silica nanostructures with tailored properties, such as a fluorescent response suitable for optical studies, superparamagnetic behavior for magnetic resonance imaging MRI contrast, and large range ordered porosity for controlled delivery. In this work, fluorescent magnetic mesoporous nanorods were physicochemical characterized and tested in preliminary biological in vitro and in vivo experiments, showing a transversal relaxivitiy of 324.68 mM−1 s−1, intense fluorescence, large specific surface area (300 m2 g−1), and biocompatibility for endothelial cells’ uptake up to 100 µg (in a 80% confluent 1.9 cm2 culture well), with no liver and kidney disability. These magnetic fluorescent nanostructures allow for multimodal MRI/optical imaging, the allocation of therapeutic moieties, and targeting of tissues with specific damage