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1.
The chitosan-coated magnetic nanoparticles (CS MNPs) were in situ synthesized by cross-linking method. In this method; during the adsorption of cationic chitosan molecules onto the surface of anionic magnetic nanoparticles (MNPs) with electrostatic interactions, tripolyphosphate (TPP) is added for ionic cross-linking of the chitosan molecules with each other. The characterization of synthesized nanoparticles was performed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS/ESCA), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermal gravimetric analysis (TGA), and vibrating sample magnetometry (VSM) analyses. The XRD and XPS analyses proved that the synthesized iron oxide was magnetite (Fe3O4). The layer of chitosan on the magnetite surface was confirmed by FTIR. TEM results demonstrated a spherical morphology. In the synthesis, at higher NH4OH concentrations, smaller sized nanoparticles were obtained. The average diameters were generally between 2 and 8?nm for CS MNPs in TEM and between 58 and 103?nm in DLS. The average diameters of bare MNPs were found as around 18?nm both in TEM and DLS. TGA results indicated that the chitosan content of CS MNPs were between 15 and 23?% by weight. Bare and CS MNPs were superparamagnetic. These nanoparticles were found non-cytotoxic on cancer cell lines (SiHa, HeLa). The synthesized MNPs have many potential applications in biomedicine including targeted drug delivery, magnetic resonance imaging?(MRI), and magnetic hyperthermia. 相似文献
2.
《Ultrasonics sonochemistry》2014,21(1):242-252
The present study was focused on the removal of methylene blue (MB) from aqueous solution by ultrasound-assisted adsorption onto the gold nanoparticles loaded on activated carbon (Au-NP-AC). This nanomaterial was characterized using different techniques such as SEM, XRD, and BET. The effects of variables such as pH, initial dye concentration, adsorbent dosage (g), temperature and sonication time (min) on MB removal were studied and using central composite design (CCD) and the optimum experimental conditions were found with desirability function (DF) combined response surface methodology (RSM). Fitting the experimental equilibrium data to various isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich models show the suitability and applicability of the Langmuir model. Analysis of experimental adsorption data to various kinetic models such as pseudo-first and second order, Elovich and intraparticle diffusion models show the applicability of the second-order equation model. The small amount of proposed adsorbent (0.01 g) is applicable for successful removal of MB (RE > 95%) in short time (1.6 min) with high adsorption capacity (104–185 mg g−1). 相似文献
3.
Magnetic nanoparticles (MNPs) of close to invar (Fe0.635Ni0.365) composition were prepared by the electrical explosion of wire using different conditions to insure different values of overheating rates. X-ray diffraction, transmission electron microscopy, low temperature nitrogen adsorption, magnetic and microwave measurements were used for the characterization of MNPs. Increase of the energy injected into the wire led to increase of the specific surface (Ssp) of the produced MNPs from 4.6 to 13.5 m2/g. The fabricated MNPs were spherical and weakly aggregated with the average weighted diameter in the range of 54–160 nm depending on the Ssp. The phase composition of FeNi MNPs consists of two solid solutions of Ni in α-phase and γ-phase lattices. The increase of the energy injected into the wire leads to increase of the α-phase from 5 to 10 wt% as the injected energy raised from 0.8 to 2.5 times the sublimation energies of the wire material. Comparative analysis of structure magnetic and microwave properties showed that the obtained MNPs are important magnetic materials with high saturation magnetization and significant zero field microwave absorption which can be expected to lead to important technological applications. 相似文献
4.
In this report, we described the preparation of Cu2+/nitrilotriacetic acids (NTA)-derivatized branch polyglycerol magnetic nanoparticles for protein adsorption with avoidance
of nonspecific interactions at the same time. Magnetic nanoparticles (MNPs) were synthesized by the coprecipitation method.
The transmission electron microscopy results showed that the average diameter of MNPs was 15.8 ± 4.6 nm. X-ray photoelectron
spectroscopy and Fourier Transform infrared measurements indicated that branch polyglycerols were grafted on MNPs via the
ring-opening polymerization of glycidol and that Cu2+ ions had been successfully immobilized on the surface of MNPs. The protein immobilization effect was characterized by UV–Vis
spectrum. The results proved that Cu2+/NTA-derivatized branch polyglycerol magnetic nanoparticles effectively adsorbed bovine haemoglobin and rarely adsorbed lysozyme
and γ-globin. 相似文献
5.
γ-Fe2O3 nanoparticles were synthesized and loaded on activated carbon. The prepared nanomaterial was characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transforms infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The γ-Fe2O3 nanoparticle-loaded activated carbon (γ-Fe2O3-NPs-AC) was used as novel adsorbent for the ultrasonic-assisted removal of methylene blue (MB) and malachite green (MG). Response surface methodology and artificial neural network were applied to model and optimize the adsorption of the MB and MG in their individual and binary solutions followed by the investigation on adsorption isotherm and kinetics. The individual effects of parameters such as pH, mass of adsorbent, ultrasonication time as well as MB and MG concentrations in addition to the effects of their possible interactions on the adsorption process were investigated. The numerical optimization revealed that the optimum adsorption (>99.5% for each dye) is obtained at 0.02 g, 15 mg L−1, 4 min and 7.0 corresponding to the adsorbent mass, each dye concentration, sonication time and pH, respectively. The Freundlich, Langmuir, Temkin and Dubinin–Radushkevich isotherms were studied. The Langmuir was found to be most applicable isotherm which predicted maximum monolayer adsorption capacities of 195.55 and 207.04 mg g−1 for the adsorption of MB and MG, respectively. The pseudo-second order model was found to be applicable for the adsorption kinetics. Blank experiments (without any adsorbent) were run to investigate the possible degradation of the dyes studied in presence of ultrasonication. No dyes degradation was observed. 相似文献
6.
The present study was aimed to removal of Cu(II) ions from aqueous solution by ultrasound-assisted adsorption onto the granular activated carbon obtained from hazelnut shells. The attention was focused on modeling the equilibrium and kinetics of Cu(II) adsorption onto the granular activated carbon. The granular activated carbon was prepared from ground dried hazelnut shells by simultaneous carbonization and activation by water steam at 950 °C for 2 h. Adsorption isotherm data were better fitted by the Langmuir model than the Freundlich model in both the absence and the presence of ultrasound. The maximum adsorption capacity of the adsorbent for Cu(II), calculated from the Langmuir isotherms, in the presence of ultrasound (3.77 mmol/g) is greater than that in the absence of ultrasound (3.14 mmol/g). The adsorption process in the absence and the presence of ultrasound obeyed to the pseudo second-order kinetics. The removal of Cu(II) ions was higher in the presence of ultrasound than in its absence, but ultrasound reduced the rate constant. The intraparticular diffusion model indicated that adsorption of Cu(II) ions on the granular activated carbon was diffusion controlled as well as that ultrasound promoted intraparticular diffusion. 相似文献
7.
Superparamagnetic nanoparticles functionalized with carboxymethyl dextran (CM-dextran) were synthesized by a two-step method. First, the magnetic nanoparticles (MNPs) coated with dextran (Mw ≈ 20000) were prepared by co-precipitation of Fe2+ and Fe3+ ions. Then, dextran on the surface of MNPs reacted with monochloroacetic acid (MCA) in alkaline condition. The influences of temperature and reactant concentration on the amount of -COOH on the surface of nanoparticles were systematically studied. The obtained MNPs coated with CM-dextran were stable over the entire range of pH and NaCl concentration. The MRI experiment indicated that the CM-dextran MNPs could potentially be used as MRI contrast agents for magnetic resonance molecular imaging. 相似文献
8.
Magnetic γ-Fe2O3 nanoparticles modificated by bis(5-bromosalicylidene)-1,3-propandiamine (M-γ-Fe2O3-NPs-BBSPN) and characterized by field emission scanning electron microscopy (FE-SEM), Fourier transforms infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). This modified compound as novel adsorbent was applied for the ultrasound-assisted removal of Pb2+ ion in combination with flame atomic absorption spectroscopy (FAAS). The influences of the effective parameters including initial Pb2+ ion concentration, pH, adsorbent mass and ultrasound time were optimized by central composite design (CCD). Maximum removal percentage of Pb2+ ion which obtained at 25 mg L−1 of Pb2+, 25 mg of adsorbent and 4 min mixing with sonication at pH 6.0. The precision of the equation obtained by CCD was confirmed by the analysis of variance and calculation of correlation coefficient relating the predicted and the experimental values of removal percentage of Pb2+ ion. The kinetic and isotherm of ultrasound-assisted removal of Pb2+ ion was well described by second-order kinetic and Langmuir isotherm model with maximum adsorption capacity of 163.57 mg g−1. 相似文献
9.
In present study, magnetic cobalt ferrite nanoparticles modified with (E)-N-(2-nitrobenzylidene)-2-(2-(2-nitrophenyl)imidazolidine-1-yl) ethaneamine (CoFe2O4-NPs-NBNPIEA) was synthesized and applied as novel adsorbent for ultrasound energy assisted adsorption of nickel(II) ions (Ni2+) from aqueous solution. The prepared adsorbent characterized by Fourier transforms infrared spectroscopy (FT-IR), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). The dependency of adsorption percentage to variables such as pH, initial Ni2+ ions concentration, adsorbent mass and ultrasound time were studied with response surface methodology (RSM) by considering the desirable functions. The quadratic model between the dependent and independent variables was built. The proposed method showed good agreement between the experimental data and predictive value, and it has been successfully employed to adsorption of Ni2+ ions from aqueous solution. Subsequently, the experimental equilibrium data at different concentration of Ni2+ ions and 10 mg amount of adsorbent mass was fitted to conventional isotherm models like Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich and it was revealed that the Langmuir is best model for explanation of behavior of experimental data. In addition, conventional kinetic models such as pseudo-first and second-order, Elovich and intraparticle diffusion were applied and it was seen that pseudo-second-order equation is suitable to fit the experimental data. 相似文献
10.
Fe3O4 magnetic nanoparticles (MNPs) were synthesized by the co-precipitation of Fe3+ and Fe2+ with ammonium hydroxide. The sodium citrate-modified Fe3O4 MNPs were prepared under Ar protection and were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and vibrating sample magnetometer (VSM). To improve the oxidation resistance of Fe3O4 MNPs, a silica layer was coated onto the modified and unmodified MNPs by the hydrolysis of tetraethoxysilane (TEOS) at 50 °C and pH 9. Afterwards, the silica-coated Fe3O4 core/shell MNPs were modified by oleic acid (OA) and were tested by IR and VSM. IR results revealed that the OA was successfully grafted onto the silica shell. The Fe3O4/SiO2 core/shell MNPs modified by OA were used to prepare water-based ferrofluids (FFs) using PEG as the second layer of surfactants. The properties of FFs were characterized using a UV-vis spectrophotometer, a Gouy magnetic balance, a laser particle size analyzer and a Brookfield LVDV-III+ rheometer. 相似文献
11.
This paper focuses on the finding best operational conditions using response surface methodology (RSM) for Rhodamine123 (R123) and Disulfine blue (DSB) dyes removal by ultrasound assisted adsorption onto Au-Fe3O4 nanoparticles loaded on activated carbon (Au-Fe3O4 NPs-AC). The influences of variables such as initial R123 (X1) and DSB concentration (X2), pH (X3), adsorbent mass (X4) and sonication time (X5) on their removal were investigated by small central composite design (CCD) under response surface methodology. The significant variables and the possible interactions among variables were investigated and estimated accordingly. The best conditions were set as: 4 min, 4.0, 0.025 g, 13.5 and 26.5 mg L−1 for sonication time, pH, adsorbent weight, initial R123 and DSB concentration, respectively. At above conditions, the adsorption equilibrium and kinetic follow the Langmuir isotherm and pseudo-second-order kinetic model, respectively. The maximum monolayer capacity (Qmax) of 71.46 and 76.38 mg g−1 for R123 and DSB show sufficiency of model for well presentation of experimental data. 相似文献
12.
Copper oxide nanoparticles loaded on activated carbon (CuO-NPs-AC) were prepared and fully analyzed and characterized with FE-SEM, XRD and FT-IR. Subsequently, this novel material was used for simultaneous ultrasound-assisted adsorption of brilliant green (BG), auramine O (AO), methylene blue (MB) and eosin yellow (EY) dyes. Problems regard to dyes spectra overlap in quaternary solution of this dyes were omitted by derivative spectrophotometric method. The best pH in quaternary system was studied by using one at a time method to achieved maximum dyes removal percentage. Subsequently, sonication time, adsorbent dosage and initial dyes concentrations influence on dyes removal was optimized by central composite design (CCD) combined with desirability function approach (DFA). Desirability score of 0.978 show optimum conditions set at sonication time (4.2 min), adsorbent mass (0.029 g), initial dyes concentration (4.5 mg L−1). Under this optimum condition the removal percentage for MB, AO, EY and BG dyes 97.58, 94.66, 96.22 and 94.93, respectively. The adsorption rate well fitted by pseudo second-order while adsorption capacity according to the Langmuir model as best equilibrium isotherm model for BG, MB, AO and EY was 20.48, 21.26, 22.34 and 21.29 mg g−1, respectively. 相似文献
13.
In present work, a graphene oxide chemically modified with 2,2′-dipyridylamine (GO-DPA), was synthesized by simple, fast and low-cost process for the simultaneous adsorption of four toxic heavy metals, Pb(II), Cd(II), Ni(II) and Cu(II), from aqueous solutions. The synthesized adsorbent was characterized by FT-IR, XRD, XPS, SEM and AFM measurements. The effects of variables such as pH solution, initial ion concentrations, adsorbent dosage and sonicating time were investigated on adsorption efficiency by rotatable central composite design. The optimum conditions, specified as 8 mg of adsorbent, 20 mg L−1 of each ion at pH 5 and short time of 4 min led to the achievement of a high adsorption capacities. Ultrasonic power had important role in shortening the adsorption time of ions by enhancing the dispersion of adsorbent in solution. The adsorption kinetic studies and equilibrium isotherms for evaluating the mechanism of adsorption process showed a good fit to the pseudo-second order and Langmuir model, respectively. The maximum adsorption capacities (Qm) of this adsorbent were 369.749, 257.201, 180.893 and 358.824 mg g−1 for lead, cadmium, nickel and copper ions, respectively. The removal performance of adsorbent on the real wastewater samples also showed the feasibility of adsorbent for applying in industrial purposes. 相似文献
14.
This article systematically evaluated the biocompatibility of multiple mammalian cell lines to 11-nm DMSA-coated Fe3O4 magnetic nanoparticles (MNPs). Cells including RAW264.7, THP-1, Hepa1-6, HepG2, HL-7702, and HeLa were incubated with six
different concentrations (0, 20, 30, 40, 50, and 100 μg/mL) of MNPs for 48 h, and then the cell labeling, iron loading, cell
viability, apoptosis, cycle, and oxidative stress were all quantitatively evaluated. The results revealed that all the cells
were effectively labeled by the nanoparticles; however, the iron loading of RAW264.7 was significantly higher than that of
other cells at any dose. The proliferations of all the cells were not significantly suppressed by MNPs at the studied dose
except HepG2 that was exposed to 100 μg/mL MNPs. The investigation of oxidative stress demonstrated that the levels of total
superoxide dismutase and xanthine oxidase had no significant changes in all the cells treated by all the doses of MNPs, while
the levels of malonyldialdehyde activity of MNP-treated cells significantly increased. The nanoparticles did not produce any
significant effect on cell cycles at any of the doses, but resulted in significant apoptosis of THP-1 and HepG2 cells at the
highest concentration of 100 μg/mL. At a concentration of 30 μg/mL which was used in human studies with an intravascular nanoparticle
imaging agent (Combidex), the nanoparticles efficiently labeled all the cells studied, but did not produce any significant
influence on their viability, oxidative stress, and apoptosis and cycle. Therefore, the nanoparticles were concluded with
better biocompatibility, which provided some useful information for its clinical applications. 相似文献
15.
Yan-Ping ChangCui-Ling Ren Qing YangZhen-Yang Zhang Li-Jun DongXing-Guo Chen De-Sheng Xue 《Applied Surface Science》2011,257(20):8610-8616
In this paper, a new adsorbent, hexadecyl functionalized magnetic silica nanoparticles (C16/SiO2-Fe3O4 NPs), was prepared by a facile method. The final product was characterized by X-ray diffractometer, transmission electron microscope, Fourier transform infrared spectrometer and vibration sample magnetometer. The preparation and adsorption conditions of the adsorbent were optimized. The adsorbent prepared maintaining volume ratio of tetraethylorthosilicate to hexadecyltrimethoxysilane at 1:0.5 and their total volume at 1100 μL exhibited high adsorption capacity. The optimum pH value for the adsorption experiments was 11.00. The adsorption behavior of Rhodamine 6G onto C16/SiO2-Fe3O4 NPs obeyed pseudo-second-order kinetic model and Langmuir isotherm. Thermodynamic data indicated that the adsorption process was spontaneous and exothermic. The adsorption capacity of the adsorbent could reach to 35.6 mg g−1, owing to the hydrophobic attraction and the enhanced electrostatic attraction. The saturation magnetization of the magnetic adsorbent was 35 emu g−1, which ensured the magnetic separation after adsorption. 相似文献
16.
This paper describes a simple way for the coating of magnetite nanoparticles (MNPs) with amorphous silica. First, MNPs were synthesized by controlled co-precipitation technique under N2 gas and then their surface was modified with trisodium citrate in order to achieve particles with improved dispersibility. Afterward, magnetite-silica core/shell nanocomposites were prepared by a sol–gel approach, using magnetic fluid including electrostatically stabilized MNPs as seeds. The prepared samples were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, zeta potential analysis and vibrating sample magnetometer (VSM) in order to study their structural and magnetic properties. FT-IR and XRD results imply that resultant nanocomposites are consisted of two compounds; Fe3O4 and SiO2 and TEM images confirm formation of their core/shell structure. TEM images also show increase in silica shell thickness from ∼5 to ∼24 nm with increase in amount of tetraethyl orthosilicate (TEOS) used during the coating process from 0.1 to 0.3 mL. Magnetic studies indicate that Fe3O4 nanoparticles remain superparamagnetic after coating with silica although their Ms values are significantly less than pristine MNPs. These core/shell nanocomposites offer a high potential for different biomedical applications due to having superparamagnetic property of magnetite and unique properties of silica. 相似文献
17.
Chitosan magnetic microspheres for technological applications: Preparation and characterization 总被引:2,自引:0,他引:2
One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800–1100 μm.The adsorption of Cu(II) onto chitosan–magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan. 相似文献
18.
Phosphorylcholine (PC)-functionalized poly(amido amine) (PAMAM) dendrimers were prepared and used as both reducing and stabilizing
agents for synthesis of highly stable and reactive gold nanoparticles (Au NPs). Biomimetic PC-functionalized PAMAM dendrimers-stabilized
gold nanoparticles (Au DSNPs) were formed by simply mixing the PC modified amine-terminated fifth-generation PAMAM dendrimers
(G5-PC) with AuCl4
− ions by controlling the pH, no additional reducing agents or other stabilizers were needed. The obtained Au DSNPs were shown
to be spherical, with particle diameters ranging from 5 to 12 nm, the sizes and growth kinetics of Au DSNPs could be tuned
by changing the pH and the initial molar ratio of dendrimers to gold as indicated by transmission electron microscopy (TEM)
and UV–Vis data. The prepared Au DSNPs showed excellent stability including: (1) stable at wide pH (7–13) values; (2) stable
at high salt concentrations up to 2 M NaCl; (3) non-specific protein adsorption resistance. More importantly, surface functionalization
could be performed by introducing desired functional groups onto the remained reactive amine groups. This was exemplified
by the glucose conjugation. The glucose conjugated Au DSNPs showed bio-specific interaction with Concanavalin A (Con A), which
induced aggregation of the Au NPs. Colorimetric detection of Con A based on the plasmon resonance of the glucose conjugated
Au DSNPs was realized. A limit of detection (LOD) for Con A was 0.6 μM, based on a signal-to-noise ratio (S/N) of 3. These
findings demonstrated that the PC modified Au DSNPs could potentially serve as a versatile nano-platform for the biomedical
applications. 相似文献
19.
Yin-Yin XuMin Zhou Hui-Juan GengJun-Jie Hao Qian-Qian OuSheng-Da Qi Hong-Li Chen Xing-Guo Chen 《Applied Surface Science》2012,258(8):3897-3902
A simplified method for synthesis of polyacrylic acid-bound iron oxide magnetic nanoparticles (Fe3O4@PAA NPs) was reported. The as-prepared nanoparticles were characterized by TEM, FT-IR, VSM and XRD. Characterization results indicated that PAA was successfully introduced onto the surface of Fe3O4 and did not cause any changes in magnetic property. The Fe3O4@PAA NPs were used to adsorb rhodamine 6G (R6G) as a model basic dye pollutant from aqueous solution. Kinetics data and adsorption isotherms were better fitted by pseudo-second-order kinetic model and Langmuir isotherm, respectively. The adsorption equilibrium could be reached at about 20 min, showing that the as-prepared adsorbent exhibited extremely rapid adsorption rate. The aqueous solution of the Yellow River was chosen as the test sample, and the results showed that the magnetic adsorbent was efficient for the removal of the basic dye in the real sample. 相似文献
20.
以砀山梨渣为原料,经磷酸酯化改性,制备一种酯化梨渣阳离子吸附剂,用批次实验法研究了其在不同实验条件下(pH值、吸附剂量、吸附质浓度和吸附时间)对金属锌离子的吸附性能。结果表明,溶液pH=3.5时,锌离子吸附达到最大值;酯化梨渣≥5g.L-1能除去锌离子为100mg.L-1溶液中的96%锌离子。改性梨渣对锌离子的吸附符合Langmuir吸附等温线模型,最大吸附能力为28.986mg.g-1。锌离子达到吸附平衡的时间为30min;准一级反应动力学方程y=-0.0615x+2.4437(r2=0.9921)描述锌离子在改性梨渣上的吸附过程。 相似文献