Search

Using a simple dipping method, a novel the magnetically driven hydrophobic polyurethane sponge (MHPS) was synthesized in this work. The isodecyl alcohol with longer carbon chain is grafted onto the sponge surface through substitution reaction and condensation reaction, and Fe3O4 nanoparticles are adhered to the sponge to give it magnetism and make it easy to collect. MHPS were characterized by Fourier transformed infrared, X-ray diffraction, scanning electron microscopy and energy dispersive spectrometers. The maximum adsorption capacity for various oils/organic solvents was 24–50 times its own weight. MHPS shows excellent reusability after ten absorption–extrusion-heating cycles. Moreover, it can selectively absorb and continuously remove oil in a wide range of water due to the combination of its high porosity, hydrophobicity and lipophilicity. The magnetism of MHPS makes it easy to collect with magnets. It is believed that MHPS has potential application prospects in oil purification and oil spill removal industry wastewater.

In the optical imaging system, the dynamic modulation transfer function (DMTF) is affected by the wave aberration of optical system, the signal resolution and transfer characteristics of detector modules, and the image blur caused by the carrier motion, which has become one of the important parameters of the photoelectric imaging system. Based on the testing principle of dynamic and static modulation transfer function of photoelectric imaging system, a DMTF measuring device was developed, in which the focal length of optical collimation system was 10 000 mm, and the speed control range of moving target was 30 mm/s~5 000 mm/s, which met the DMTF test of photoelectric imaging system with long focal length. A series of experiments were carried out, and the results show that the repeatability of DMTF measurement is better than 0.01, and the uncertainty of measurement can reach to U= 0.05 (k=2).

In this paper, a 5-aminoisophthalic acid (APTA) functionalized magnetic composite nanoparticles (Fe3O4@SiO2-APTA) are reported for adsorbing methylene blue (MB) from wastewater. The nanoparticles were analyzed by high resolution transmission electron microscopy, scanning electron microscopy, fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, N2 adsorption/desorption, and vibrating sample magnetometer. The factors affecting the adsorption of methylene blue, initial concentration, adsorption time and pH of the solution were studied in detail. It was found that the adsorption capacity of magnetic composite nanoparticles depended on the pH of the solution. The results show that Fe3O4@SiO2-APTA exhibits an excellent adsorption performance with the maximum adsorption capacity (46.24 mg/g) for MB at pH 11. In addition, experimental results show that the adsorption of MB on Fe3O4@SiO2-APTA nanoparticles conforms to the pseudo-second-order kinetic model the Freundlich isotherm model, and reaches the adsorption equilibrium within 30 min. After consecutive use five times, adsorption percentages of MB were retained 70%, showing a good reusability of the adsorbent. The superior adsorption performances of Fe3O4@SiO2-APTA are attributed to electrostatic interaction, hydrogen bonding, and chemical sorption compared with recent adsorbents. Therefore, this work provides a promising approach for removal of MB with high efficiency, low cost.

In this paper, novel ferrocene functionalized sandwich-type core–shell structure magnetic nanocomposites (Fe3O4@SiO2–FC/COOH) are synthesized using the Fe3O4 as the core and the ferrocene and 5-Aminoisophthalic acid as the functional dendrimers. Taking advantage of high redox activity benefit of ferrocene, Fe3O4@SiO2–FC/COOH is fabricated to adsorb Cr(VI) and reduce it to nontoxic Cr(III) in aqueous solution. The structure and morphology of prepared magnetic adsorbent are characterized by FTIR, XRD, SEM, XPS, TEM, EDS, and TGA. Moreover, the effects of different factors (such as solution pH, adsorption time, adsorption temperature, adsorbent dosage etc.) on adsorption are evaluated. XPS analysis indicates that Cr(VI) is successfully reduced to nontoxic Cr(III) after adsorption by Fe3O4@SiO2–FC/COOH. The Fe3O4@SiO2–FC/COOH exhibits excellent removal efficiency with a maximum Cr(VI) adsorption of 228.395 mg g−1 at pH 2.0. In addition, the adsorption experimental results fit well with the Freundlich isotherm model and the pseudo-second-order kinetic model. Desorption experiment results demonstrate that the regenerated adsorption capacity can exceed more than 95% after five times adsorption–desorption cycles. Therefore, this work provides a promising approach for Cr(VI) removal from water solution.

In this paper, carboxylated ethylenediamine functionalization Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2-EDA-COOH NPs) have been developed in order to remove methylene blue (MB) from aqueous solution. The chemical structure, morphology and magnetic characteristics of the magnetic composite nanoparticles were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), High resolution transmission electron microscopy (HR-TEM), Scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). To explore the truth, some methylene blue adsorption influenced factors of initial concentration, contact time and solution pH were at length investigated. The results showed that the absorption capacity depended strongly on pH, and the maximum adsorption value for MB (43.15 mg/g) was obtained at pH 10. In addition, the equilibrium was attained within 60 min, and the adsorption kinetics and adsorption isotherms data can be well accorded with pseudo-second-order kinetic model and Freundlich isotherm model, respectively. Most importantly, remarkable enhancement in adsorption capacity for MB is achieved than other reported adsorbents. It is worth noting that adsorbents can be quickly recovered from aqueous solution by external magnet. Finally, the plausible adsorption mechanism was briefly discussed. Our results suggest that novel nanoparticle Fe3O4@SiO2-EDA-COOH is a promising adsorbent in improving adsorption performance of MB from aqueous solution.

A brand-new environmental-friendly magnetic cellulosic adsorbent MnFe2O4@Cel-g-p(AA-DMC) was synthesized by natural cellulose and easy-recovered magnetic particles MnFe2O4. Magnetic cellulose composites were characterized by SEM, TEM, XPS, XRD, BET, VSM, TGA and FTIR. The MnFe2O4NPs could activate the peroxymonosulfate (PMS) to produce various reactive oxygen species (ROS). Accordingly, magnetic cellulose composites can synergistic adsorption degradation of dyes from organic wastewater. The Congo red (CR) removal efficiency by MnFe2O4@Cel-g-p(AA-DMC) via PMS activated by MnFe2O4 reached a maximum of 96.9% and only 9% reduction after four adsorption-desorption cycles, indicating the stability and recoverability of adsorbent. It is worth noting that adsorbents can be quickly recovered from aqueous solution by external magnet owing to superior saturation magnetization (35.44 emu·g-1). A possible degradation mechanism of CR on the MnFe2O4@Cel-g-p(AA-DMC) composite was proposed. The results suggest that adsorbent display strong potential for the removal of CR dyes from organic wastewater.

In this paper, using amidoxime as a functional monomer, different generations of polyamidoxime dendrimer magnetic microspheres (Fe3O4@SiO2-g-PAMAM-AO) were fabricated to adsorb Pb2+ and Ni2+ in aqueous solution. The magnetic adsorbents were characterized by FTIR, XRD, SEM, XPS, TEM, EDS, TGA and BET. The effects of different factors (such as solution pH, adsorption time, adsorption temperature, adsorbent dosage etc.) on adsorption were evaluated. Fe3O4@SiO2-g-PAMAM-AO has a maximum Pb(II) adsorption of 157.25 mg g−1 (100 mg L−1) at pH 5.5. Furthermore, Fe3O4@SiO2-g-PAMAM-AO showed an excellent adsorption performance for the removal of Ni(II) with a maximum adsorption capacity of 191.78 mg g−1 (100 mg L−1) at pH 8.0. The sorption isotherm data fitted the Freundlich isotherm model well. Adsorption kinetics analysis showed that it was best described by the pseudo-second-order rate model. Desorption experiment results showed that the adsorbent can be reused in the adsorption–desorption cycles.

Zircon U–Pb dating, geochemistry, and Sr–Nd–Hf isotope data are reported for monzonite from the Qingshanpu pluton on the eastern margin of Longshoushan. The zircon LA-ICP-MS U–Pb age data showed that the emplacement age of the monzonite is 442.6 ± 4.8 Ma. The rocks are characterized by high SiO2 contents (73.15%–73.85%), high K2O contents (3.67%–3.99%), and low P2O5 contents (0.042%–0.049%). The aluminum saturation index was 1.03–1.05, and the molecular number of standard corundum was 0.58%–0.77%. Rocks are enriched in Rb, Sr, U, K, and Pb and depleted in Nb, Ti, Zr, P, and Eu, thereby indicating that they are weakly peraluminous I-type granites. The monzonite in the Qingshanpu pluton had lower ISr values, which ranged from 0.70850 to 0.70904, and the εNd(t) values ranged from -8.54 to -6.49. The εHf(t) values ranged from -9.75 to 0.42, and the two-stage model age TC DM ranged from 1406 to 2043 Ma. This study concluded that the North Qilian subducted beneath the Alxa Plate at the end of the Early Paleozoic, causing elastic collision and eventually leading to closure. During elastic collision, several parts of the orogenic belt collapsed and were dismantled. The remelted ancient crust mixed with a small amount of mantle material during its ascent and finally formed the Qingshanbao pluton.

Using chemical co-precipitation method to make a magnetic magnetite, dithiocarbamate-multifunctional embedded in the carboxyl group to synthesize a novel nanocomposite Fe3O4@SiO2-DTPA-DTC for adsorption the Co2+ from aqueous solution. The Fe3O4@SiO2-DTPA-DTC composites were characterized by XRD, SEM, TEM, FT-IR, XPS, TGA and VSM in this study. From the adsorption study, removal efficiency of Co2+ on Fe3O4@SiO2-DTPA-DTC is up to 98%. The adsorption reached equilibrium within 5 min. The optimum pH was recorded to be 6.0. The adsorption process fitted with Freundlich isotherm model and adsorption mechanism is chemical adsorption. After five-cycle adsorption test, the nanocomposites maintain high removal efficiency. The results showed that the Fe3O4@SiO2-DTPA-DTC can be considered as a promising adsorbent to adsorption the Co2+ from aqueous solution.