Magnetic Iron Nanoparticles Research Articles

Green Synthesis of Magnetic Fe2O3 Nanoparticle with Chenopodium glaucum L. as Recyclable Heterogeneous Catalyst for One-Pot Reactions and Heavy Metal Adsorption.

The growth of the environment depends upon developing greener and ecological methods for managing pollutants and contamination from industrial wastewater, which causes significant effects on human health. The removal of these pollutants from wastewater using nanomaterials covers an ecological method that is free from expensive and secondary pollution. In this report, we developed magnetic iron nanoparticles from Chenopodium glaucum (CG), which showed excellent adsorption capacity at pH 5 for selective Hg2+ and Pb2+ metal ions among various heavy metal ions, with maximum adsorption capacities of 96.9 and 94.1%, respectively. These metals' adsorption process conforms to the Langmuir model, which suggests that monolayer adsorption transpires on CG-Fe2O3 nanoparticles. CG-Fe2O3 nanoparticles also act as an efficient and recyclable heterogeneous catalyst for one-pot synthesis of xanthene derivatives, yielding products with high yields (up to 97%) and excellent purity (crystalline form) within a short timeframe (6 min) using microwave irradiations (at 120 W).

A comprehensive study on RSM optimization of the influencing variables on loading/releasing of ciprofloxacin onto/from magnetic iron nanoparticles

Fe3O4 MNPs were synthesized by the co-precipitation method and characterized via SEM, EDX, FTIR, XRD, VSM, TGA, and x-ray map. Its pHpzc was obtained at 5.4. The loading and releasing conditions for Ciprofloxacin (CIP) on/from Fe3O4 magnetic nanoparticles (MNPs) were optimized via response surface methodology (RSM). We found that pH was the most influential factor in the loading and releasing processes. The center point conditions for the loading were pH 7, CIP concentration of 14 ppm, adsorbent dose of 11 mg, and shaking time of 9 h, while for the release process, were pH 5.1, sample dose of 11 mg, and releasing time of 5.1 h. The optimal RSM run conditions for loading were pH: 5, CCIP: 13 ppm, dose: 7 mg, time: 20 h, and for the releasing process were pH: 2.7, dose: 11 mg, time: 7 h.

Preparation and Identification of Magnetic Iron Nanoparticle based on a Natural Hydrogel and its Performance in Targeted Drug Delivery

Billions of dollars are spent annually in the world to treat and investigate problems caused by drug side effects. According to the estimates of health researchers, about 40%of people who take medicine suffer from side effects. In this way, the necessity of using a targeted system in order to deliver medicine to the desired place without damaging healthy tissues is felt more than ever. In recent years, targeted drug delivery systems based on nanoparticles have received much attention. Meanwhile, the use of natural polymers is more suitable for various purposes in drug delivery systems in terms of indicating greater biological compatibility with the body and being non-toxic.In this research, the natural hydrogel extracted from the seeds of the Plantago ovata, which is loaded on the bed of magnetic iron nanoparticles, was used to entrap the drugmefenamic acid. In order to achieve this goal, at the beginning, magnetic iron nanoparticles were prepared by co-precipitation method using iron (II) and iron (III) oxides, and then a coating of silica was created on its surface, then the hydrocolloid of Plantago ovata was extracted from its seed, in order to connect the magnetite nanoparticles and the polymer extracted from the Plantago ovata, the surface of both components was modified by vinyl-functional groups. Next, radical polymerization under heat was used to connect the particles and trap the drug, after that the release of the drug from the polymer capsule was checked by UV-Vis device. Before examining the drug release, the resulting product was identified by FT-IR, XRD, VSM, DLS, TGA, SEM analysis. Therefore, the obtained results indicated that the natural polymer was correctly loaded on the desired magnetic substrate and the drug mefenamic acid was trapped inside the hydrogel networks and polymer capsule. Therefore, the drug can be directed in a controlled and targeted manner by the magnetic field, and the release of the drug was done well and at an acceptable speed.

High-frequency magnetic response of superparamagnetic composites of spherical Fe and Fe3O4 nanoparticles

The response of arrays of magnetic nanoparticles (MNPs) of cubic anisotropy materials (magnetite or iron) to high-frequency (sub-GHz) field is investigated utilizing micromagnetic simulations. Composites of MNPs embedded in dielectric media are of interest as core materials for high-frequency power microconverters with low eddy-current losses. Going beyond the macrospin approximation for MNPs (including internal spin structure), we simulate the magnetization dynamics of arrays of spherical and periodically arranged MNPs under periodic boundary conditions and in the presence of thermal fluctuations of the magnetization within the stochastic thermal field. Analyzing the dependence of the dynamical response on the size of the MNPs, we find the size to be crucial for exciting regular magnetization oscillations at room temperature and reducing hysteresis loss. The efficiency of the dynamical response of composites of high-magnetization-metal (iron) MNPs is compared to that of magnetite nanocomposites. We find the sub-GHz susceptibility of magnetite-containing nanocomposite to be comparable to that of the iron MNPs despite the lower saturation magnetization of Fe3O4, (at the volumetric ratio of the magnetic phase of 0.13, susceptibility is χ≈1.6 for 5 nm Fe and ≈1.4 for 12 nm Fe3O4 MNPs at T=300 K and frequency of 0.1 GHz).

Targeted Drug Delivery through the Synthesis of Magnetite Nanoparticle by Co-Precipitation Method and Creating a Silica Coating on it

Billions of dollars are spent annually in the world to treat and investigate problems caused by drug side effects. According to the estimation of health researchers, a huge part of people who take medicine suffer from complications caused by it. In this way, the necessity of using a targeted system in order to deliver medicine to the targeted place without damaging healthy tissues is felt more than before. In recent years, targeted drug delivery systems based on nanoparticles have received much attention. In the same direction, in this research, co-precipitation method was used to prepare magnetic nanoparticles using iron(|) and iron(||) oxides, and further, according to the synthesis steps of magnetite nanoparticles (MNPs) and the mechanism of formation and identification of magnetite nanoparticles ( Fe3O4) by examining the infrared pattern (FT-IR) obtained from Fe3O4 nanoparticles, the results of the magnetometric test (VSM) of Fe3O4 nanoparticles, X-ray diffraction pattern (XRD) of Fe3O4 nanoparticles, Field Emission Scanning Electron Microscope (FE-SEM) images obtained from Fe3O4 nanoparticles was discussed. After this stage, silica- coated iron nanoparticles (Fe3O4@SiO2) were prepared, and the infrared (FT-IR) pattern of Fe3O4@SiO2) was also investigated. It is worth mentioning that the mechanism of formation and identification of magnetic silica-coated iron nanoparticles (Fe3O4@SiO2) has been described in detail. Therefore, the obtained results indicate that the drug can be guided in a controlled and targeted manner by the magnetic field, and the results of the FE-SEM images show that the obtained product has a spherical morphology and the particle size distribution was less than 100 nm. Therefore, spherical shape and the symmetry of these particles can be helpful for their movement in the liquid mediu.

Impact of Fe3O4-porphyrin hybrid nanoparticles on wheat: Physiological and metabolic advance

Iron-magnetic nanoparticles (Fe-NMPs) are widely used in environmental remediation, while porphyrin-based hybrid materials anchored to silica-coated Fe3O4-nanoparticles (Fe3O4-NPs) have been used for water disinfection purposes. To assess their safety on plants, especially concerning potential environmental release, it was investigated for the first time, the impact on plants of a silica-coated Fe3O4-NPs bearing a porphyrinic formulation (FORM) - FORM@NMP. Additionally, FORM alone and the magnetic nanoparticles without FORM anchored (NH2@NMP) were used for comparison. Wheat (Triticum aestivum L.) was chosen as a model species and was subjected to three environmentally relevant doses during germination and tiller development through root application. Morphological, physiological, and metabolic parameters were assessed. Despite a modest biomass decrease and alterations in membrane properties, no major impairments in germination or seedling development were observed. During tiller phase, both Fe3O4-NPs increased leaf length, and photosynthesis exhibited varied impacts: both Fe3O4-NPs and FORM alone increased pigments; only Fe3O4-NPs promoted gas exchange; all treatments improved the photochemical phase. Regarding oxidative stress, lipid peroxidation decreased in FORM and FORM@NMP, yet with increased O2-• in FORM@NMP; total flavonoids decreased in NH2@NMP and antioxidant enzymes declined across all materials. Phenolic profiling revealed a generalized trend towards a decrease in flavones. In conclusion, these nanoparticles can modulate wheat physiology/metabolism without apparently inducing phytotoxicity at low doses and during short-time exposure. Environmental implicationIron-magnetic nanoparticles are widely used in environmental remediation and fertilization, besides of new applications continuously being developed, making them emerging contaminants. Soil is a major sink for these nanoparticles and their fate and potential environmental risks in ecosystems must be addressed to achieve more sustainable environmental applications. Furthermore, as the reuse of treated wastewater for agricultural irrigation is being claimed, it is of major importance to disclose the impact on crops of the nanoparticles used for wastewater decontamination, such as those proposed in this work.

Biosynthesis Optimization of Antibacterial-Magnetic Iron Oxide Nanoparticles from Bacillus megaterium.

The occurrence of antibiotic resistance on common bacterial agents and the need to use new generations of antibiotics have led to the use of various strategies for production. Taking inspiration from nature, using bio-imitation patterns, in addition to the low cost of production, is advantageous and highly accurate. In this research, we were able to control the temperature, shake, and synthesis time of the synthesis conditions of Bacillus megaterium bacteria as a model for the synthesis of magnetic iron nanoparticles and optimize the ratio of reducing salt to bacterial regenerating agents as well as the concentration of salt to create iron oxide nanoparticles with more favorable properties and produced with more antibacterial properties. Bacterial growth was investigated by changing the incubation times of pre-culture and overnight culture in the range of the logarithmic phase. The synthesis time, salt ratio, and concentration were optimized to achieve the size, charge, colloidal stability, and magnetic and antibacterial properties of nanoparticles. The amount of the effective substance produced by the bacteria was selected by measuring the amount of the active substance synthesized using the free radical reduction (DPPH) method. With the help of DPPH, the duration of the synthesis was determined to be one week. Characterizations such as UV-vis spectroscopy, FTIR, FESEM, X-ray, and scattering optical dynamics were performed and showed that the nanoparticles synthesized with a salt concentration of 80mM and a bacterial suspension to salt ratio of 2:1 are smaller in size and have a light scattering index, a PDI index close to 0.1, and a greater amount of reducing salt used in the reaction during one week compared to other samples. Moreover, they had more antibacterial properties than the concentration of 100mM. As a result, better characteristics and more antibacterial properties than common antibiotics were created on E. coli and Bacillus cereus.

Adsorption and removal ability of magnetic pineapple peel biochar-Based for amoxicillin

In this study, pineapple peel (PAP) was successfully modified into a novel magnetic biochar (M–BCPAP) by co-precipitating it with iron magnetic nanoparticles (MNP) for amoxicillin removal from aqueous solutions. Characterization of the synthesized M-BCPAP was carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Brunauer – Emmett – Teller (BET) surface analysis. The suitability of the adsorption of Amoxicillin (AMX) on M-BCPAP with Freundlich, Langmuir, and Temkin isotherm models was investigated and it was determined that the isotherm with the best fitness with adsorption was the Langmuir isotherm (R 2=0.9998), which suggests single-layer adsorption. A maximum adsorption capacity of 18.6 mg/g was obtained with Langmuir isotherm. The pseudo-second-order kinetic model had a better fit with the best correlation to the kinetic data. Various adsorption parameters such as pH (2–6), initial AMX concentration (10–100 mg/L), amount of adsorbent (50–125 mg) and adsorption time (10–180 min) were investigated in the adsorption of AMX on M-BCPAP. As a result, the obtained data show that the synthesized magnetic biochar is a highly effective and low-cost, environmentally friendly alternative adsorbent in the removal of amoxicillin from aqueous solutions.

Biodistribution Analysis of Peptide-Coated Magnetic Iron Nanoparticles: A Simple and Quantitative Method.

Biodistribution tracks compounds or molecules of interest in vivo to understand a compound's anticipated efficacy and safety. Nanoparticles deliver nucleic acid and drug payloads and enhance tumor permeability due to multiple properties such as high surface area to volume ratio, surface functionalization, and modifications. Studying the in vivo biodistribution of nanoparticles documents the effectiveness and safety of nanoparticles and facilitates a more application-driven approach for nanoparticle development that allows for more successful translation into clinical use. In this study, we present a relatively simple method to determine the biodistribution of magnetic iron nanoparticles in mice. In vitro, cells take up branched amphiphilic peptide-coated magnetic nanobeads (BAPc-MNBs) like their counterparts, i.e., branched amphiphilic peptide capsules (BAPCs) with a hollow water-filled core. Both BAPc-MNBs and BAPCs have widespread applications as a nanodelivery system. We evaluated the BAPc-MNBs tissue distribution in wild-type mice injected intravenously (i.v.), intraperitoneally (i.p.), or orally gavaged to understand the biological interactions and to further the development of branched amphiphilic peptide-based nanoparticles. The magnetic nanoparticles allowed collection of the BAPc-MNBs from multiple organs by magnetic bead sorting, followed by a high-throughput screening for iron content. When injected i.v., nanoparticles were distributed widely to various organs before elimination from the system via the intestines in feces. The spleen accumulated the highest amount of BAPc-MNBs in mice administered NPs via i.v. and i.p. but not via oral gavage. Taken together, these data demonstrate that the magnetic sorting not only allowed quantification of the BAPc-MNBs but also identified the distribution of BAPc-MNBs after distinct administration methods.

Chlorella vulgaris extract conjugated magnetic iron nanoparticles in nile tilapia (Oreochromis niloticus): Growth promoting, immunostimulant and antioxidant role and combating against the synergistic infection with Ichthyophthirius multifiliis and Aeromonashydrophila

Nile tilapia reared under intensive conditions was more susceptible for Ichthyophthirius multifilii (I. multifiliis) infection eliciting higher mortality, lower productive rate and further bacterial coinfection with Aeromonas hydrophila (A. hydrophila). The higher potency of magnetic field of iron oxide nanoparticles (NPs) can kill pathogens through inhibiting their viability. Herein, coating of Chlorella vulgaris extract (ChVE) with magnetic iron oxide NPs (Mag iron NPs) can create an external magnetic field that facilitates their release inside the targeted tissues. Thus, the current study is focused on application of new functionalized properties of Mag iron NPs in combination with ChVE and their efficacy to alleviate I. multifiliis and subsequent infection with A. hydrophila in Nile tilapia. Four hundred fingerlings were divided into: control group (with no additives), three groups fed control diet supplemented with ChVE, Mag iron NPs and ChVE@Mag iron NPs for 90 days. At the end of feeding trial fish were challenged with I. multifiliis and at 9 days post challenge was coinfected by A. hydrophila. A remarkable higher growth rate and an improved feed conversion ratio were detected in group fed ChVE@Mag iron-NPs. The maximum expression of antioxidant enzymes in skin and gills tissues (GSH-Px, CAT, and SOD) which came in parallel with higher serum activities of these enzymes was identified in groups received ChVE@Mag iron-NPs. Furthermore, group fed a combination of ChVE and Mag iron-NPs showed a boosted immune response (higher lysozyme, IgM, ACH50, and MPO) prior to challenge with I. multifiliis. In contrast, fish fed ChVE@Mag iron-NPs supplemented diet had lower infection (decreased by 62%) and mortality rates (decreased by 84%), as well as less visible white spots (decreased by 92 % at 12 dpi) on the body surfaces and mucous score. Interestingly, post I. multifiliis the excessive inflammatory response in gill and skin tissues was subsided by feeding on ChVE@Mag iron-NPs as proved by down regulation of IL-1β, TNFα, COX-2 and iNOS and upregulation of IL-10, and IgM, IgT and Muc-2 genes. Notably, group exposed to I. multifiliis-showed higher mortality when exposed to Aeromonas hydrophilia (increased by 43 %) while group fed ChVE@Mag iron-NPs exhibited lower morality (2%). Moreover, the bacterial loads of A. hydrophilia in fish infected by I. multifiliis and fed control diet were higher than those received dietary supplement of ChVE, Mag iron-NPs and the most reduced load was obtained in group fed ChVE@Mag iron-NPs at 7 dpi. In conclusion, ChVE@Mag iron-NPs fed fish had stronger immune barrier and antioxidant functions of skin and gills, and better survival following I. multifiliis and A. hydrophilia infection.

Adsorption of Chromium, Copper, Lead, Selenium, and Zinc ions into ecofriendly synthesized magnetic iron nanoparticles.

The iron nanoparticles (Fe-NPs) have been synthesized using an environmentally friendly and simple green synthesis method. This study aims to obtain an aqueous extract from natural material wastes for synthesizing Fe-NPs. The produced Fe-NPs were evaluated as adsorbents for removing Pb, Se, Cu, Zn, and Cr from aqueous solutions. The formation of Fe-NPs was observed on exposure of the aqueous extract to the ferrous chloride and ferric chloride solutions. The characterization of the synthesized Fe-NPs was carried out using different instrumental techniques. As a function of the initial metal ion concentration, contact time, and various doses, the removal of the heavy metal ions was investigated. The UV-Vis spectrum of Fe-NPs showed a peak at 386 nm, 386 nm, 400 nm, 420 nm, 210 nm, 215 nm, and 272 nm of banana, pomegranate, opuntia, orange, potato, and onion, respectively. The FT-IR spectra confirmed the attachment of bioactive molecules from plants on the Fe-NPs surface. The effective reduction of metal ions was greatly aided by the -OH functional groups. The functional groups were examined and responsible for adsorption process by nanoparticle powder sample, these peaks are 3400 cm-1, 2900 cm-1, 1600 cm-1,1000 cm-1, and 1550 cm-1. The magnetization measurements revealed superparamagnetic behavior in the produced iron oxide nanoparticles. Heavy metal ions uptake followed a time, dose, and initial concentration-dependent profile, with maximum removal efficiency at 45 min, 0.4 g, and 3.0 mg/L of metal concentration, respectively.

Iron magnetic nanoparticles coated with different loadings of polyvinylpyrrolidone: Evaluation of magnetic properties and morphology

Polyvinylpyrrolidone-coated iron magnetic nanoparticles (PVP-Fe MNPs) have proven to be useful materials for several applications. However, the relationship between the PVP loading and the properties of these materials is not currently well understood. In this study, we examine the changes in the magnetic properties and morphology of PVP-Fe MNPs as a result of varying the PVP loading. The samples were synthesised by a co-precipitation technique in a homogeneous solution containing PVP and iron salts. Fourier transform infrared spectroscopy (FTIR) indicates the presence of PVP on the surface of the core-Fe MNPs. Meanwhile, vibrating sample magnetometer (VSM) reveals that the PVP loading had an inverse relationship with the magnetic properties (saturation magnetisation, Ms, remanence magnetisation, Mr and coercivity, Hc), which was mainly impacted by the morphology of the resultant PVP-Fe MNPs. Thermogravimetric (TGA) and carbon and nitrogen elemental analyses were used to characterise the proportion of PVP bound to Fe-MNPs. The results suggest that the properties of these PVP-Fe MNPs can be tuned by the PVP loading used in their synthesis, allowing these materials to be tailored for the targeted application.

The Influence of Thermoplastic Composite Recycling on the Additive Manufacturing Process and In-Use Phase as Candidate Materials for Wearable Devices Applications.

Fused filament fabrication (FFF) is a popular additive manufacturing (AM) method for creating thermoplastic parts with intricate geometrical designs. Pure thermoplastic materials utilized in FFF, whose polymeric matrix is reinforced with other materials, such as carbon fibers (CFs), introduce products with advanced mechanical properties. However, since not all of these materials are biodegradable, the need for recycling and reuse immediately emerges to address the significant problem of how to dispose of their waste. The proposed study evaluates the printability, surface morphology and in vitro toxicity of two thermoplastic-based composite materials commonly used in wearable device manufacturing to provide enhanced properties and functionalities, making them suitable for various applications in the field of wearable devices. Tritan Copolyester TX1501 with 7.3% chopped CFs (cCFs) and Polyamide 12 (PA12) with 8.6%cCFs and 7.5% iron Magnetic Nanoparticles (MNPs)-Fe4O3 were used in the discrete ascending cycles of recycling, focusing on the surface quality performance optimization of the printed parts. Through stereoscopy evaluation, under-extrusion, and over-extrusion defects, as well as non-uniform material flow, are assessed in order to first investigate the influence of various process parameters' application on the printing quality of each material and, second, to analyze the optimal value fluctuation of the printing parameters throughout the recycling cycles of the materials. The results indicate that after applying certain adjustments to the main printing parameter values, the examined recycled reinforced materials are still effectively 3D printed even after multiple cycles of recycling. A morphology examination using scanning electron microscope (SEM) revealed surface alterations, while a cytotoxicity assessment revealed the adverse effects of both materials in the form of cell viability and the release of proinflammatory cytokines in the cell culture medium.

Magnetically Controlled 3D Cartilage Regeneration.

The cartilage regeneration field has not yet overcome the issue of effective "shaping": growing regenerated cartilage in the desired shape, and maintaining that shape, is problematic. This study reports on a new method of cartilage regeneration in which the cartilage is shaped in three dimensions. Since cartilage is composed only of cartilage cells and an abundant extracellular matrix with no blood circulation, once it is damaged, the lack of nutrient supply means that it is difficult to repair. Scaffold-free cell sheet technology plays an important role in cartilage regeneration, avoiding inflammation and immune response caused by scaffold materials. However, cartilage regenerated from the cell sheet needs to be sculpted and shaped before it can be used for cartilage defect transplantation. In this study, we used a new ultra-strong magnetic-responsive Fe3O4 nanoparticle (MNP) to shape the cartilage in vitro. Super-magnetic Fe3O4 microspheres are manufactured by co-assembling negatively charged Cetyltrimethylammonium bromide (CTAB) and positively charged Fe3+ under solvothermal conditions. The Fe3O4 MNPs are swallowed by chondrocytes, and the MNP-labeled chondrocytes are acted upon by the magnetic field. The predetermined magnetic force makes the tissues coalesce to form a multilayer cell sheet with a predetermined shape. The shaped cartilage tissue is regenerated in the transplanted body, and the nano magnetic control particles do not affect cell viability. The nanoparticles in this study improve the efficiency of cell interaction through super-magnetic modification, and to a certain extent change the way the cells absorb magnetic iron nanoparticles. This phenomenon allows a more orderly and compact alignment of the cartilage cell extracellular matrix, promotes ECM precipitation and cartilage tissue maturation, and improves the efficiency of cartilage regeneration. The magnetic bionic structure, which contains specific magnetic particle-labeled cells, is deposited layer by layer to generate a three-dimensional structure with repair function, and further induce the production of cartilage. This study describes a new method for the regeneration of tissue engineered cartilage which has broad application prospects in regenerative medicine.

Wax appearance temperature study of model waxy oils: influence of nanofluids prepared with iron magnetic nanoparticles

Wax deposition creates many problems in the crude oil production, storage and transportation. The present work is in line with the efforts being made to address wax deposition issues. Nanofluids were prepared with different concentrations of the Fe-magnetic nanoparticles (Fe-MNPs). The same were used to monitor the wax appearance temperature (WAT) of the model waxy oil samples through pour point and differential scanning calorimetry in comparison to the control sample. The effect of increase in the amount of nanofluid and concentration of the Fe-MNPs in the nanofluid had the synergistic effect and the nanofluid prepared with 5% Fe-MNPs exhibited the most positive effect on the reduction of pour point. The results demonstrated that the nanofluid decreased the WAT and increased the flowability and could be used successfully as potential flow improver for real crude oils in industry for controlling the wax deposition issues.

Polyolefin-derived carbon nanotubes as magnetic catalysts for wet peroxide oxidation of paracetamol in aqueous solutions

This work deals with developing feasible valorization technologies to prepare carbon nanotubes (CNTs) from plastic solid waste and demonstrate their application in catalytic wet peroxide oxidation (CWPO). CNTs were synthesized by catalytic chemical vapor deposition (CCVD) at 850 ºC, considering low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) as carbon precursors representative of urban plastic solid waste. Iron oxide nanoparticles supported in alumina, previously synthesized by sol-gel, were used as catalysts in the CCVD process. TEM micrographs allow us to determine 41 nm as the average outer diameter of the CNTs and to visualize magnetic iron nanoparticles (ca. 10 nm) embedded inside the CNTs (ca. 6.4 % of content measured as ashes). These magnetic nanoparticles were kept in the CNT structure even after the purification of the CNTs with sulphuric acid, allowing to obtain magnetic CNTs. All purified and non-purified CNTs prepared from the polyolefins were assessed as catalysts in CWPO of paracetamol (PCM), used as a model pharmaceutical contaminant in water at CPCM,0 = 100 μg mL−1 (CH2O2,0 = 472 μg mL−1, CCNT = 2.5 g L−1, pH0 = 3.5 and T = 80 °C). The concentrations of PCM, H2O2, aromatic and total phenolic compounds were monitored for 24 h. All CNTs showed catalytic activity, allowing the complete degradation of PCM at 6 h of reaction time. The stability and reusability of materials are tested and proved in CWPO.

Single and Ternary Removal of Heavy Metals from Aqueous Solution Using Fe3O4 Magnetic Nano-particles

This research aims to investigate the use of magnetic iron nano-particles (FeN) for the removal of heavy metals under single and ternary scenarios. The methodology includes synthesis of FeN using chemical precipitation approach, batch experiments for single and ternary metals removal, isotherm and kinetic studies, thermos-dynamic study and assessing the effect of different parameters on the adsorption process. The results showed that the maximum removal for As and Hg was achieved at a pH of 7, while a pH of 6 provided a slightly higher removal of Cd than a pH of 7 at an optimum mixing time of 120 minutes. The optimum adsorption capacities of As, Cd and Hg at the initial concentration of 200 ppm were 260, 280 and 75.0 mg/g in the case of single metal removal against 91.5, 237.8 and 341.5 mg/g in the case of ternary combination, respectively. The removal of all metals increased with increasing the FeN dose and the mixing time, while it decreased with the increase of the initial concentration. The removal efficiency was affected strongly by the presence of multiple metals, while As removal decreased sharply and Hg removal increased significantly. Adsorption selectivity is affected negatively by the increase in atomic weight and atomic radius. In the case of single-metal removal, fitting of isotherm models can be ranked as Langmuir>Freundlich>Temkin>D-R for As and Cd and Temkin>Freundlich>D-R>Langmuir for Hg, while contradictory results were obtained in the case of ternary combination. Kinetic studies found that the adsorption follows the pseudo-second-order model with R2=0.99. For all metals, the adsorption process is highly favourable at higher temperatures and is endothermic in nature with (ΔHo) of 10.91, 23.86 and 0.163 for As, Cd and Hg, respectively. Coating of FeN with silica resulted in lower removal efficiency for all metals up to 50%. It can be concluded that FeN can be successfully used for the removal of heavy metals either through the single or ternary approach, but the single approach provides a higher performance. KEYWORDS: Nano-materials, Magnetite iron, Adsorption, Arsenic, Cadmium, Mercury, Lead.

Performance of Eversa Transform 2.0 Lipase in Ester Production Using Babassu Oil (Orbignya sp.) and Tucuman Oil (Astrocaryum vulgar): A Comparative Study between Liquid and Immobilized Forms in Fe3O4 Nanoparticles

In this study, biodiesel was produced through the enzymatic esterification of vegetable oils from two common Brazilian palm trees: babassu and tucuman. The oils were hydrolyzed by a chemical route and their free fatty acids esterified with ethanol and methanol using the lipase enzyme Eversa® Transform 2.0 in free forms and supported in iron magnetic nanoparticles (Fe3O4) (enzymatic load: 80 UpNPBg−1). These enzymatic reactions were performed at an oil–alcohol molar ratio of 1:1, reaction temperature of 37 °C, agitation at 150 rpm, and reaction times of 2, 4, 6 and 8 h for the reactions catalyzed by the soluble enzyme and 8 h for the reactions using the biocatalyst. The conversions of fatty acids in ethyl and methyl esters obtained were monitored by gas chromatography (CG). The results obtained from ester synthesis using enzyme catalysts in free form were better: babassu 52.6% (methanol) and 57.5% (ethanol), and for tucuman 96.7% (methanol) and 93.4% (ethanol). In the case of immobilized enzymes, the results obtained ranged from 68.7% to 82.2% for babassu and from 32.5% to 86.0% for tucuman, with three cycles of reuse and without significant catalyst loss. Molecular coupling studies revealed the structures of lipase and that linoleic acid bonded near the active site of the enzyme with the best free energy of −6.5 Kcal/mol.

The spike protein of SARS-CoV-2 can be detected by electrochemical impedance spectroscopy using antibody desorption from iron magnetic nanoparticles.

SARS-CoV-2 is a matter of concern. Here, biosensors were prepared using iron magnetic nanoparticles containing antibodies against the receptor binding domain (RBD) of the spike protein. Antibodies were adsorbed to nanoparticles in three configurations, including direct adsorption without functionalization (DANPs). Nanoparticles were added to a glassy carbon electrode and connected to an electrochemical cell. Electrochemical impedance spectroscopy and ELISA experiments indicated that antibodies were desorbed from the DANPs upon the addition of the RBD. DANPs-based biosensors produced linear curves with decreasing charge transfer resistance due to the removal of antibodies. Thus, a detection method can be based on antibody desorption.

Efficient photo-Fenton catalysis using magnetic iron nanoparticles decorated boron nitride quantum dots: theoretical and experimental investigations.

To achieve the efficient removal of pharmaceutical wastes, novel photo-Fenton catalysts, iron-decorated boron nitride quantum dots (Fe@BNQDs) were prepared. Fe@BNQDs were characterized using XRD, SEM-EDX, FTIR, and UV-Vis spectrophotometry. The decoration of Fe on the surface of BNQDs enhanced the catalytic efficiency due to the photo-Fenton process. Photo-Fenton catalytic degradation of folic acid was investigated under UV and visible light. The influence of H2O2, catalyst dose, and temperature on the degradation yield of folic acid was investigated using Response Surface Methodology. Moreover, the efficiency of the photocatalysts and kinetics was investigated. Radical trapping experiments revealed that holes were the main dominant species in the photo-Fenton degradation mechanism and BNQDs played active roles because of their hole extraction ability. Additionally, active species such as e- and O2 -˙ have a medium effect. The computational simulation was utilized to provide insights into this fundamental process, and for this purpose, electronic and optical properties were calculated.