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•Novel magnetic pullulan (MP) hydrogels were designed.•These prepared MP hydrogels were for the first time used as Fenton-like catalysts.•MP hydrogels exhibited excellent degradation ...activity, reusability and stability.•Degradation mechanism for tetracycline hydrochloride in our MP3/H2O2 system was proposed.
Magnetic nanoparticles that can be employed as Fenton-like catalysts Fenton-like catalysts are attractive materials for degrading antibiotics. In this study, we facilely prepared novel magnetic pullulan (MP) hydrogels by doping modified magnetic nanoparticles into pullulan matrices, which could enhance catalytic degradation performance and strengthen the stability of resulting hydrogels. This is the first time that MP hydrogels have been fabricated successfully and used as Fenton-like catalysts for tetracycline hydrochloride (TCH) degradation. MP hydrogels were characterized and their catalytic TCH degradation abilities were also investigated. The optimized conditions (pH value, Fe3O4 content, H2O2 content and TCH concentration) for TCH degradation were investigated. The optimized system showed excellent degradation efficiency for TCH. Further, the degradation mechanism was comprehensively studied. Finally, synthesized MP hydrogels showed impressive reusability and stability in the cycle experiment. Thus, our findings would open new possibilities to develop magnetic hydrogels in eliminating antibiotic contaminants.
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•A magnetic ion-imprinted polymer was prepared for selective adsorption of Cr(VI).•Polymers have relatively fast adsorption kinetics and high adsorption capacity.•Polymers show highly ...selectivity for Cr(VI) in presence of other competitive ions.•Magnetic Cr(VI) ion-imprinted polymers show very high stability and reusability.
Fe3O4 magnetic nanoparticles were prepared by hydrothermal synthesis and their surface was modified by the sol-gel method. Polymers imprinted with magnetic Cr (VI) were prepared by using Cr2O72− as template ion, 4-vinyl pyridine (4-VP) as monomer, isopropanol as solvent and Fe3O4 as matrix. The effects of solvent type, amount of Cr (VI) addition and volume of crosslinking agent on the adsorption properties of the imprinted polymers were investigated. The polymers were characterized by Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). The adsorption equilibrium was reached within 50 min, and the maximum adsorption capacity was 201.55 mg·g−1. The adsorption process conformed to the Langmuir model, and the results of kinetic fitting showed that the pseudo-first-order kinetic model applied. In the Cr2O72−/AlF4− and Cr2O72−/CrO42− competitive systems, the imprinted polymer showed good selectivity to the template ions, with relative selectivity factors of 6.91 and 5.99, respectively. When the imprinted polymer was reused 6 times, the adsorption capacity decreased by only 8.2%, demonstrating good reusability.
Two-dimensional Ti3C2T x MXene-based hybrids-anchored magnetic metal nanoparticles show a huge potential application as effective wave absorbers due to the synergistic electromagnetic (EM) loss ...effect. In this work, uniform and size-controllable nickel, cobalt, or nickel–cobalt alloy nanoparticles were in situ grown on the surface of MXene via a facile and moderate co-solvothermal method for the first time. As an example, a nickel nanoparticles-anchored MXene (Ni@MXene) hybrid was homodispersed into dielectric polyvinylidene fluoride to develop its EM wave-absorbing capacity to a great extent. As expected, the results showed strong reflection loss (RLmin = −52.6 dB at 8.4 GHz), broad effective absorption bandwidth (EAB = 3.7 GHz including 71% of X-band), low loading (10 wt % Ni@MXene), and thin thickness (3.0 mm). By adjusting the sample thickness, EAB can cover completely the whole X-band with a maximum of 6.1 GHz, showing a huge potential of Ni@MXene hybrid applying as aircraft stealth coating. The mechanism analyses revealed that the excellent impedance matching, magnetocoupling effect, conductance, magnetic loss, and multiple scatterings contribute to the splendid EM wave-absorbing performance of the Ni@MXene hybrid. Considering the excellent overall performance, the Ni@MXene hybrid was identified as a promising candidate for EM wave absorption.
Previous attempts to review the literature on magnetic nanomaterials for hyperthermia-based therapy focused primarily on magnetic fluid hyperthermia (MFH) using mono metallic/metal oxide ...nanoparticles. The term “hyperthermia” in the literature was also confined only to include use of heat for therapeutic applications. Recently, there have been a number of publications demonstrating magnetic nanoparticle-based hyperthermia to generate local heat resulting in the release of drugs either bound to the magnetic nanoparticle or encapsulated within polymeric matrices. In this review article, we present a case for broadening the meaning of the term “hyperthermia” by including thermotherapy as well as magnetically modulated controlled drug delivery. We provide a classification for controlled drug delivery using hyperthermia: Hyperthermia-based controlled drug delivery through bond breaking (DBB) and hyperthermia-based controlled drug delivery through enhanced permeability (DEP). The review also covers, for the first time, core–shell type magnetic nanomaterials, especially nanoshells prepared using layer-by-layer self-assembly, for the application of hyperthermia-based therapy and controlled drug delivery. The highlight of the review article is to portray potential opportunities for the combination of hyperthermia-based therapy and controlled drug release paradigms -towards successful application in personalized medicine.
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Interference of organic compounds in the matrix of heavy metal solution could suppress their pre-concentration and detection processes. Therefore, this work aimed to develop simple and facile methods ...for separation of heavy metals before ICP-MS analysis. Fe3O4@SiO2@TiO2 core-double shell magnetic adsorbent was prepared and characterized by TEM, SEM, FTIR, XRD and surface area, and tested for Magnetic Solid Phase Extraction (MSPE) of Cu(II), Zn(II), Cd(II) and Pb(II). TEM micrograph of Fe3O4@SiO2@TiO2 reveals the uniform coating of TiO2 layer of about 20nm onto the Fe3O4@SiO2 nanoparticles and indicates that all nanoparticles are monodispersed and uniform. The saturation magnetization from the room-temperature hysteresis loops of Fe3O4 and Fe3O4@SiO2@TiO2 was found to be 72 and 40emug−1, respectively, suggesting good separability of the nanoparticles. The Fe3O4@SiO2@TiO2 showed maximum adsorption capacity of 125, 137, 148 and 160mgg−1 for Cu(II), Zn(II), Cd(II) and Pb(II) respectively, and the process was found to fit with the second order kinetic model and Langmuir isotherm. Fe3O4@SiO2@TiO2 showed efficient photocatalytic decomposition for tartrazine and sunset yellow (consider as Interfering organic compounds) in aqueous solution under the irradiation of UV light. The maximum recovery% was achieved at pH 5, by elution with 10mL of 2M nitric acid solution. The LODs were found to be 0.066, 0.049, 0.041 and 0.082µgL−1 for Cu(II), Zn(II), Cd(II) and Pb(II), respectively while the LOQs were found to be 0.20, 0.15, 0.12 and 0.25µgL−1 for Cu(II), Zn(II), Cd(II) and Pb(II), respectively.
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•Fe3O4@SiO2@TiO2 is used for magnetic solid phase MSPE of Cu(II), Zn(II), Cd(II) and Pb(II) prior to ICP-MS.•Fe3O4@SiO2@TiO2 acts as magnet, photocatalyst and acid resistant adsorbent nanoparticle.•The process includes enrichment of metals simultaneously with degradation of interfering organic matrix.•LOQs were 0.20, 0.15, 0.12, 0.25µgL−1 for Cu(II), Zn(II), Cd(II) and Pb(II).
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•Better fabrication and modification methods of magnetic materials were identified.•The optimized Fe3O4@Arg can achieve 95% harvesting efficiency.•The optimal method has a low cost of ...347 USD/t of algal biomass harvested.•The amino-acid content and the amino group number play roles in better harvesting.
Harvesting is a critical step in microalgae-based biodiesel production. Oleaginous microalgae harvesting by magnetic nanomaterials has gained attention because of the advantages of higher efficiency, lower cost, and convenient operation. In the present study, Fe3O4 magnetic nanoparticles (MNPs) were fabricated using two different methods (chemical coprecipitation and thermal decomposition), modified with amino acid using three different approaches (ultrasonic, long-time mixing, and “one-step” approaches), and utilized for oleaginous microalgae Chlorella sp. HQ harvesting. The results showed that the Fe3O4 MNPs synthesized by the chemical coprecipitation method achieved superior performance when considering both harvesting efficiency and fabrication cost. For the amino-acid modification, the one-step approach outcompeted the other approaches. At a dosage of 200 mg/L, the optimized Fe3O4@Arginine MNPs could achieve a harvesting efficiency of 95% with a low cost of only 347 USD/t of harvested algal biomass. Both the amino-acid content on the NPs and the number of amino groups in the amino acid molecules played a role in improving the harvesting performance.
•T-MNPs were synthesized and applied for the photocatalytic ozonation process.•Photocatalytic ozonation is a powerful oxidation process for water/wastewater treatment.•Almost 100 % of 10 mg/L CFT ...removed after 15 min treatment by process.•The mineralization rate was determined to be 75.5 % after 15 min treatment by process.•T-MNPs presented high level of photocatalytic activity and excellent recyclability.
The presence of antibiotics in the environment leads to microbial resistance in humans and pathogenic microbes. Given the resistance of antibiotics even after conventional wastewater treatments, the present study is centered on the removal of ceftazide (CFT) from aqueous solutions by the photocatalytic ozonation process using TiO2 magnetic nanoparticles (T-MNPs). The effects of a number of operational parameters such as pH, initial CFT concentration, ozone concentration, reaction time on the degradation of CFT was thoroughly studied by the photocatalytic process. Under the optimum conditions (CFT concentration of 10 mg/L, pH 11, catalyst dosage of 1.0 g/L and ozone flow of 0.22 g/h), the removal efficiency and mineralization of 100 was 75.5 % were obtained for CFT after a 15-min treatment. Following on, the reusability of the photocatalyst was evaluated indicating a 5.8 % drop in the removal performance after six consecutive cycles of use. The mechanism for the degradation of CFT was predominantly governed by the formation of OH radicals. In conclusion, the photocatalytic ozonation process can significantly remove CFT and seems to be a suitable alternative to the others methods used for removal of antibiotics from aqueous solutions.
•Synthesis of FexCo1-x good quality nanoparticles by the chemical reduction technique.•FexCo1-x nanoparticles with bcc cubic structure and no impurities.•FexCo1-x nanoparticles with good soft ...magnetic behaviour.•FexCo1-x nanoparticles with saturation magnetization up to 235 emu/g.•Good magnetorheological behaviour by using Fe47Co53 nanoparticles as fluid fillers.
We present results concerning the synthesis of FexCo1-x (0 < x < 1) alloy nanoparticles (NPs) with different compositions by the chemical reduction technique and subsequent structural (XRD patterns), morphological (TEM images) and magnetic (VSM magnetometry) characterization. We have got excellent quality NPs in the cubic bcc structure showing a room temperature magnetization as high as 235 emu/g for the Fe66Co34 composition alloy. Powder of composition Fe47Co53 was used to fabricate a magnetorheological fluid (MRF) by using mineral oil as carrier liquid and Aerosil 300 as additive to control the viscosity of the fluid. This MRF showed a strong magnetorheological response with a superior performance under applied magnetic field up to 616.7 kA/m and good reversibility after demagnetization process. At that highest applied magnetic field, we determined a yield stress value of 2729 Pa, that competes well with the best ones reported in the most recent literature.
Surfaces of iron oxide of ferrimagnetic magnetite (Fe
3
O
4
) nanoparticles (MNPs) prepared by Massart's method and their functionalized form (f-MNPs) with succinic acid, L-arginine, oxalic acid, ...citric acid, and glutamic acid were studied by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR-S), UV-vis, thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and reflection electron energy loss spectroscopy (REELS). The XPS analysis of elements and their chemical states at the surface of MNPs and f-MNPs revealed differences in chemical bonding of atoms, content of carbon–oxygen groups, iron oxide forms, iron oxide magnetic properties, adsorbed molecules, surface coverage, and overlayer thickness, whereas the Auger parameters (derived from XPS and Auger spectra) and elastic and inelastic scattering probabilities of electrons on atoms and valence band electrons (derived from REELS spectra) indicated modification of surface charge redistribution, electronic, and optical properties. These modified properties of f-MNPs influenced their biological properties. The surfaces biocompatible for L929 cells showed various cytotoxicity for HeLa cells (10.8–5.3% of cell death), the highest for MNPs functionalized with oxalic acid. The samples exhibiting the largest efficiency possessed smaller surface coverage and thickness of adsorbed molecules layers, the highest content of oxygen and carbon–oxygen functionalizing groups, the highest ratio of lattice O
2−
and OH
−
to C sp
2
hybridizations on MNP surface, the highest ratio of adsorbed O
−
and OH
−
to C sp
2
hybridizations on adsorbed molecule layers, the closest electronic and optical properties to Fe
3
O
4
, and the lowest degree of admolecule polymerization. This high cytotoxicity was attributed to interaction of cells with a surface, where increased content of oxygen groups, adsorbed O
−
, and OH
−
may play the role of additional adsorption and catalytic sites and a large content of adsorbed molecule layers of carboxylic groups facilitating Fenton reaction kinetics leading to cell damage.
Norfloxacin is widely used owing to its strong bactericidal effect on Gram-negative bacteria. However, the residual norfloxacin in the environment can be biomagnified via food chain and may damage ...the human liver and delay the bone development of minors. Present work described a reliable and sensitive smartphone colorimetric sensing system based on cobalt-doped Fe3O4 magnetic nanoparticles (Co-Fe3O4 MNPs) for the visual detection of norfloxacin. Compared with Fe3O4, Co-Fe3O4 MNPs earned more remarkably peroxidase-like activity and TMB (colorless) was rapidly oxidized to oxTMB (blue) with the presence of H2O2. Interestingly, the addition of low concentration of norfloxacin can accelerate the color reaction process of TMB, and blue deepening of the solution can be observed with the naked eye. However, after adding high concentration of norfloxacin, the activity of nanozyme was inhibited, resulting in the gradual fading of the solution. Based on this principle, a colorimetric sensor integrated with smartphone RGB mode was established. The visual sensor exhibited good linearity for norfloxacin monitoring in the range of 0.13-2.51 µmol/L and 17.5-100 µmol/L. The limit of visual detection was 0.08 µmol/L. In the actual water sample analysis, the spiked recoveries of norfloxacin were over the range of 95.7%-104.7 %. These results demonstrated that the visual sensor was a convenient and fast method for the efficient and accurate detection of norfloxacin in water, which may have broad application prospect.
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