Fast Precipitation Method Research Articles

Synthesis of Carnation-Like ZnO for Photocatalytic Degradation of Antibiotics, Including Tetracycline Hydrochloride

ZnO has been known to be an excellent photocatalyst and production of suitable morphology by cheap methods to increase catalytic efficiency is important in practical applications. In this study, a fast precipitation method was used to produce the carnation-like morphology to improve the performance of ZnO in the removal of tetracycline hydrochloride (TCH). The precursor of zinc nitrate, precipitation agents of sodium hydroxide, and trisodium were used to control the morphology of ZnO. The characterization of as-prepared material was confirmed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, diffuse reflectance ultraviolet-visible, and N2 adsorption/desorption isotherms. As a result, the ZnO appeared with a regular and uniform three-dimensional carnation-like morphology and consisted of numerous nanosheets with a thickness of 0.013 μm. The average size of the ZnO flowers was 5 μm. In addition, the plausible formation mechanism of nanoflower with time was proposed. The effects of reaction conditions on the catalytic performance of ZnO were thoroughly examined, and its performance was compared with those of other ZnO forms and other materials. As-prepared ZnO showed to efficiently decompose TCH with the decompose efficiency and rate constant of 89.92% and 0.038 min−1, respectively. Moreover, the •O2− and h+ were key active species in the decomposition of the TCH process.

The Effect of Copper Nano-capsules on the Control of Two Spotted Spider Mite (Tetranychusurticae)

Common bean (Phaseolus vulgaris L.) is one of the most important and widely cultivated Legume in the world. The two-spotted spider mite (TTSM), is one of the most important agricultural pests. This research provided some evidence of the applicability of CuO nano particles and nano capsule for controlling TTSM. To evaluate the effect of copper nano-capsules on the populations of TSSM from red beans, Akhtar variety was used. This bean is a susceptible variety. To evaluate the effect of copper nano-capsules on the populations of TSSM from red beans, Akhtar variety was used. This bean is a susceptible variety. Five experiments were carried out, including spraying with copper nanocapsule (Cu2O) at 5 levels of concentration (1) without nano-capsule copper (2) nanocapsules 1 g / l (3) nano capsules 2.5 g / l (4) nano capsules 4 Grams per liter 5. Nanocapsule was 5.5 grams per liter. The time of spraying was the simultaneous appearance of the first flower buds in each plant. According to the results, the use of copper nanocapsules has a significant effect on decreasing population of the pest. This can be different by change the concentration of nanocapsules. Copper oxide nanoparticles were first synthesized via a fast precipitation method. The prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy.

Rapid photo-degradation of toxic dye pollutants: green synthesis of mono-disperse Fe3O4–CeO2 nanocomposites in the presence of lemon extract

Fe3O4 nanoparticles were first synthesized via a fast precipitation method. CeO2 and Fe3O4–CeO2 nanocomposites then were prepared using hydrothermal method with a green procedure in the presence of lemon extract. The effect of time, pH and applied magnetic field on the size and shape of nanostructures were investigated. The prepared products were characterized using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Vibrating sample magnetometer was used to study the magnetic property of the products. The results illustrated super-paramagnetic behaviour of Fe3O4 nanoparticles. The photo-catalytic behaviour of Fe3O4–CeO2 nanocomposites was evaluated using the degradation of two azo dyes under ultraviolet light irradiation. The results show that the prepared nanocomposites have potential application for magnetic and photo-catalytic performance.

The FRET performance and aggregation-induced emission of two-dimensional organic-inorganic perovskite, and its application to the determination of Hg(II)

The authors describe the synthesis of a two-dimensional organic-inorganic perovskite of the type NH3(CH2)10NH3)PbBr4 by a fast precipitation method. The resulting powder under photoecitation at 270 nm exhibits yellow luminescence (peaking at 550 nm) in DMSO/water mixtures if the ratio is bigger than 4/6. On addition of Hg(II) and a rhodamine spirolactam, ring opening occurs and colorimetric and fluorescent responses can be seen. Specifically, the emission at 550 nm gradually decreases and a new emission peak appears at 585 nm (corresponding to the emission peak of RBEA-Hg(II) complex) while the color of the solution gradually turns to pink under visible light. The emission peak of the modified perovskite overlaps the 585 nm absorption of rhodamine B, and this results in a FRET effect whose Forster radius (donor-acceptor distance) is calculated from decay time data to be 10.4 A. Based on these findings, a FRET-based assay for Hg(II) was worked that has a 2.4 μM detection limit.

Preparation of vaterite CaCO3 microspheres by fast precipitation method

AbstractHere we describe a rapid approach for synthesizing pure vaterite calcium carbonate microspheres through a fast precipitation method. The precipitated CaCO3 microspheres were produced in alkaline aqueous media with the addition of sodium citrate at room temperature. The obtained microspheres were investigated with scanning electron microscopy, dynamic light scattering, fourier transform infrared spectroscopy and powder X-ray diffraction. The characterization results reveal that the obtained microspheres are pure vaterite with an average diameter of 5 μm. The possible reason for the formation of vaterite CaCO3 microspheres instead of calcite has also been discussed.

Controlled synthesis of hydroxyapatite microspheres with hierarchical structure and high cell viability

Monodispersed vaterite CaCO3 microspheres with regular morphology were synthesized by a fast precipitation method in the presence of sodium carboxyl methylcellulose, and then used as a template to induce the formation of hydroxyapatite microspheres in a hydrothermal reaction. By regulating reaction temperature and amount of surfactant sodiumdodecyl benzene sulfonate, the secondary nano building blocks of hydroxyapatite microspheres can be accurately controlled between nanoplates and nanorods. Based on XRD, FTIR and HRTEM characterizations, a possible transformation mechanism is proposed. In vitro cell experiments show that hydroxyapatite microspheres with hierarchical structure produce significantly high cell viability. Moreover, the hydroxyapatite microspheres with nanoplates promoted cell reproduction better than those with nanorods.

Facile fabrication of novel red phosphorus-CdS composite photocatalysts for H2 evolution under visible light irradiation

Novel red phosphorus-CdS (P-CdS) composite photocatalysts were successfully prepared through a facile and fast precipitation method. The samples were then characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS) and photoluminescence emission spectroscopy (PL). The photocatalytic activity was evaluated by H2 generation in the aqueous solution containing Na2S/Na2SO3 as hole scavengers under visible light irradiation (λ ≥ 400 nm). The results show the optimal P molar ratio was 10 mol% and the corresponding H2 production rate reached 923 umol h−1 g−1, which is about 2.53 times higher than that of CdS sample. Meanwhile, the composite photocatalysts show favorable photostability. The enhanced photocatalytic activity can be attributed to the highly effective charge separation on P-CdS hybrids as confirmed by PL result. Also, a possible photocatalytic mechanism of the P-CdS composites is proposed and discussed in detail.

室温快速液相沉淀法制备吡嗪四甲酸钐配合物及其光致发光性能研究

室温快速液相沉淀法制备吡嗪四甲酸钐配合物及其光致发光性能研究

Porous spherical CaO-based sorbents via PSS-assisted fast precipitation for CO2 capture.

In this paper, we report the development of synthetic CaO-based sorbents via a fast precipitation method with the assistance of sodium poly(styrenesulfonate) (PSS). The effect of PSS on physical properties of the CaO sorbents and their CO2 capture performance were investigated. The presence of PSS dispersed the CaO particles effectively as well as increased their specific surface area and pore volume remarkably. The obtained porous spherical structure facilitated CO2 to diffuse and react with inner CaO effectively, resulting in a significant improvement in initial CO2 carbonation capacity. A proper amount of Mg(2+) precursor solution was doped during a fast precipitation process to gain CaO-based sorbents with a high anti-sintering property, which maintained the porous spherical structure with the high specific surface area. CaO-based sorbents derived from a MgxCa1-xCO3 precursor existed in the form of CaO and MgO. The homogeneous distribution of MgO in the CaO-based sorbents effectively prevented the CaO crystallite from growing and sintering, further resulting in the favorable long-term durability with carbonation capacity of about 52.0% after 30 carbonation/calcination cycles.

Synthesis and electrochemical performance of nanostructured LiMnPO4/C composites as lithium-ion battery cathode by a precipitation technique

A fast precipitation method is adopted for synthesis of nano-MnPO4·H2O, with MnSO4·H2O, H3PO4, NH4NO3 and NaOH as raw materials. MnPO4·H2O precipitate is characterized by XRD (X-ray diffraction) and SEM (scanning electron microscope). Fine-sized, well-crystallized, carbon-coated LiMnPO4/C nano-composites are obtained by using mechanochemical activation assisted carbothermal reduction route from as-prepared MnPO4·H2O, Li2CO3 and PVA (polyvinyl alcohol). The effect of calcination temperature on the structure and properties of obtained materials is investigated by XRD, SEM, TEM (transmission electron microscopy) and electrochemical measurements. The in situ 6.8wt% carbon coated LiMnPO4/C displays discharge specific capacity of 124mAhg−1 at 0.05C rate and 108mAhg−1 at 1C rate. The capacity retention is nearly 100% after 20 cycles at 1C rate. This mechanochemical activation assisted precipitation technique is a facile approach for the fabrication of LiMnPO4 cathode materials.

Functionalized IRMOF-3: An Efficient Heterogeneous Catalyst for the Cycloaddition of Allyl Glycidyl Ether and CO<SUB>2</SUB>

Functionalized metal organic framework F-IRMOF-3 having quaternary ammonium group was prepared by a fast precipitation and solvothermal method. They showed good catalytic performance for the cycloaddition of allyl glycidyl ether (AGE) and carbon dioxide without any solvent. F-IRMOF-3 with a larger alkyl chain structure and more nucleophilic anion exhibited better reactivity for the cycloaddition reaction. The introduction of a defective ZnO to F-IRMOF-3 by the fast precipitation method becomes more advantageous than the conventional solvothermal method for the cycloaddition reaction due to acid-base bifunctional active sites. The F-IRMOF-3 can be easily recovered and reused without any considerable loss of initial activity.

Fast precipitation of uniform CaCO3 nanospheres and their transformation to hollow hydroxyapatite nanospheres

Shape-controlled synthesis of calcium carbonate with specific polymorphs can be achieved by the assistance of organic additives. In this study, highly uniform nanosized calcium carbonate spheres were synthesized by a fast precipitation method in the presence of a simple polymer, poly(styrene sulfonate) (PSS). The polymorph of the synthesized calcium carbonate products changes from pure calcite in PSS-free reactions to vaterite in PSS-containing (1-50 g/L) reactions. The effect of PSS on the formation of vaterite can be attributed to the two aspects: decrease of driving force by reducing the interfacial energy, and phase stabilization effect caused by the adsorbed PSS. A higher PSS concentration (50 g/L) results in highly uniform vaterite nanospheres of 400-500 nm in diameter. Furthermore, PSS is found more effective to induce the formation of vaterite in the Ca(2+)-rich reaction condition (Ca(2+):CO(3)(2-)=5:1) than in the CO(3)(2-)-rich conditions (Ca(2+):CO(3)(2-)=1:5). It has also been found that different mixing mode of the calcium and carbonate precursor solutions has a significant influence on the size distribution of the products. Finally, with a controlled anion-exchange method, the as-prepared vaterite nanospheres can be easily transformed to hollow hydroxyapatite spheres, which exhibit great potential to be used as the drug carriers due to their considerably high surface area and biocompatibility.

Mixed conducting catalyst support materials for the direct methanol fuel cell

Finely dispersed Pt- and Pt/Ru-particles have been deposited on high surface-area ruthenium dioxide (RuO 2) using the Petrow and Allen method [U.S. Patent No. 4,044,193 (23 August 1977)]. RuO 2 has been synthesized according to different preparation methods. It turned out that the product showing the highest surface area could be produced by a simple fast precipitation method. The electrocatalytic activities of catalysts on different ruthenium oxide supports have been investigated in half-cell experiments by stationary current voltage measurements. Pt/Ru-catalysts deposited on a Vulcan XC-72 carbon black have been used for comparison. X-ray analysis methods (XRD, EDX) have been used to characterize the composition and crystallinity of the materials and their geometric surface areas have been determined by the BET method. It turned out that the electric conductivity of the RuO 2 materials was comparable to that observed for Vulcan XC-72. Furthermore, RuO 2 materials having a BET surface area above 125 m 2/g could be synthesized. (Vulcan XC-71: ∼250 m 2/g). Surprisingly, no significant electrochemical activity was found when Pt/Ru was deposited on freshly precipitated hydrous RuO 2. Deposition of noble metals on calcined RuO 2 resulted in electrochemical activities comparable to the ones obtained for the Vulcan XC-72 support. Thus, no extraordinary enhancement of catalytic activity for the methanol has been observed when RuO 2 oxide was used as a mixed conducting catalyst support.

Baseline Diene Conjugation in LDL Lipids as a Direct Measure of In Vivo LDL Oxidation

To additionally test validity of the recently developed method (LDL baseline diene conjugation, LDL-BDC) for determination of circulating oxidized LDL. A detailed comparison between the ultracentrifugation and heparin precipitation methods for LDL isolation was performed to test suitability of the fast precipitation method. Validity of LDL-BDC as an indicator of circulating oxidized LDL was tested by comparing LDL-BDC to results obtained by the immunological autoantibody method. BDC values in LDL isolated by heparin precipitation did not differ from those isolated by sequential ultracentrifugation. While highest amount of diene conjugation was found in LDL (40% of that in serum), substantial amounts were also found in VLDL (31%) and HDL (25%). When analyzed in the same samples, assays for the titer of autoantibodies against oxidized LDL and LDL-BDC were found to show good correlation (r = 0.57, p = 0.001, n = 29). These results, together with thus far conducted studies on clinical applicability of the method, indicate that LDL-BDC is a promising candidate in search for a method for estimation of LDL oxidation in vivo.