scholarly journals Facile Preparation of CNT/Ag2S Nanocomposites with Improved Visible and NIR Light Photocatalytic Degradation Activity and Their Catalytic Mechanism

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 503 ◽  
Author(s):  
Lijing Di ◽  
Tao Xian ◽  
Xiaofeng Sun ◽  
Hongqin Li ◽  
Yongjie Zhou ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Dye Degradation ◽  
Average Particle Size ◽  
Hybrid Nanocomposites ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Average Particle ◽  
Nir Light ◽  
Photocatalytic Activities ◽  
Ag2s Nanoparticles

In this work, a series of carbon nanotubes (CNT)/Ag2S hybrid nanocomposites were successfully prepared by a facile precipitation method. Transmission electron microscope (TEM) observation indicates that Ag2S nanoparticles with an average particle size of ~25 nm are uniformly anchored on the surface of CNT. The photocatalytic activities of the CNT/Ag2S nanocomposites were investigated toward the degradation of rhodamine B (RhB) under visible and near-infrared (NIR) light irradiation. It is shown that the nanocomposites exhibit obviously enhanced visible and NIR light photocatalytic activities compared with bare Ag2S nanoparticles. Moreover, the recycling photocatalytic experiment demonstrates that the CNT/Ag2S nanocomposites possess excellent photocatalytic stability. The photoelectrochemical and photoluminescence measurements reveal the efficient separation of photogenerated charges in the CNT/Ag2S nanocomposites. This is the dominant reason behind the improvement of the photocatalytic activity. Based on active species trapping experiments, the possible photocatalytic mechanism of CNT/Ag2S nanocomposites for dye degradation under visible and NIR light irradiation was proposed.

scholarly journals Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag2S/BiFeO3 Heterojunction Composites under Visible-Light Irradiation

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 399 ◽  
Author(s):  
Lijing Di ◽  
Hua Yang ◽  
Tao Xian ◽  
Xueqin Liu ◽  
Xiujuan Chen
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Dye Degradation ◽  
Synergistic Effects ◽  
Active Species ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Photoexcited Electron ◽  
Catalytic Mechanisms ◽  
Ag2s Nanoparticles

Z-scheme Ag2S/BiFeO3 heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag2S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO3 particles (500–800 nm) to form Ag2S/BiFeO3 heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag2S/BiFeO3 heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag2S/BiFeO3 composites exhibit much improved photocatalytic activities when compared with bare Ag2S and BiFeO3. The optimum composite sample was observed to be 15% Ag2S/BiFeO3 with an Ag2S mass fraction of 15%. Furthermore, the addition of H2O2 can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag2S/BiFeO3 composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag2S/BiFeO3 composites were proposed and discussed.

Fabrication of monoclinic BiVO4 photocatalyst film and its photocatalytic activity for organic pollutant removal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saranyoo Chaiwichian ◽  
Buagun Samran
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Average Particle Size ◽  
Pollutant Removal ◽  
Light Irradiation ◽  
Average Particle ◽  
Film Sample ◽  
Acid Orange 7 ◽  
Acid Orange ◽  
X Ray

Abstract Monoclinic BiVO4 photocatalyst films decorated on glass substrates were successfully fabricated via a dip-coating technique with different annealing temperatures of 400 °C, 450 °C, 500°C, and 550 °C. All of the physical and chemical properties of as-prepared BiVO4 photocatalyst film samples were investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectra techniques. The results revealed that the as-prepared BiVO4 photocatalyst film samples retained a monoclinic phase with an average particle size of about 50 – 100 nm. Moreover, the BiVO4 photocatalyst film samples showed a strong photoabsorption edge in the range of visible light with the band gap energy of 2.46 eV. The photocatalytic activities of all the film samples were tested by the degradation of model acid orange 7 under visible light irradiation. The BiVO4 photocatalyst film sample annealed at a temperature of 500 °C showed the highest photoactivity efficiency compared with other film samples, reaching up to 51%within 180 min. In addition, the stability and reusability of BiVO4 photocatalyst film sample made with an annealing temperature of 500 °C did not show loss of photodegradation efficiency of acid orange 7 after ten recycles. A likely mechanism of the photocatalytic process was established by trapping experiments, indicating that the hydroxyl radical scavenger species can be considered to play a key role for acid orange 7 degradation under visible light irradiation.

Enhanced oral bioavailability of nisoldipine-piperine-loaded poly-lactic-co-glycolic acid nanoparticles

2017 ◽  
Vol 6 (6) ◽  
pp. 517-526 ◽  
Author(s):  
Permender Rathee ◽  
Anjoo Kamboj ◽  
Shabir Sidhu
Keyword(s):  
Oral Bioavailability ◽  
Drug Loading ◽  
Average Particle Size ◽  
Entrapment Efficiency ◽  
Pharmacokinetic Interaction ◽  
Precipitation Method ◽  
Pharmacokinetic Studies ◽  
Average Particle

AbstractBackground:Piperine helps in the improvement of bioavailability through pharmacokinetic interaction by modulating metabolism when administered with other drugs. Nisoldipine is a substrate for cytochrome P4503A4 enzymes. The study was undertaken to assess the influence of piperine on the pharmacokinetics and pharmacodynamics of nisoldipine nanoparticles in rats.Methods:Optimization studies of nanoparticles were performed using Taguchi L9 orthogonal array, and the nanoparticles were formulated by the precipitation method. The influence of piperine and nanoparticles was evaluated by means of in vivo kinetic and dynamic studies by oral administration in rats.Results:The entrapment efficiency, drug loading, ζ potential, and average particle size of optimized nisoldipine-piperine nanoparticles was 89.77±1.06%, 13.6±0.56%, −26.5 mV, and 132±7.21 nm, respectively. The in vitro release in 0.1 n HCl and 6.8 pH phosphate buffer was 96.9±0.48% and 98.3±0.26%, respectively. Pharmacokinetic studies showed a 4.9-fold increase in oral bioavailability and a >28.376±1.32% reduction in systemic blood pressure by using nanoparticles as compared to control (nisoldipine suspension) in Wistar rats.Conclusion:The results revealed that piperine being an inhibitor of cytochrome P4503A4 enzymes enhanced the bioavailability of nisoldipine by 4.9-fold in nanoparticles.

scholarly journals Preparation and characterization of domperidone nanoparticles for dissolution improvement

2018 ◽  
Vol 27 (1) ◽  
pp. 39-52
Author(s):  
Mohammed Sabar Al-lami ◽  
Malath H. Oudah ◽  
Firas A. Rahi
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Methyl Cellulose ◽  
Precipitation Method ◽  
Average Particle ◽  
Antisolvent Precipitation ◽  
Stirring Time

This study was carried out to prepare and characterize domperidone nanoparticles to enhance solubility and the release rate. Domperidone is practically insoluble in water and has low and an erratic bioavailability range from 13%-17%. The domperidone nanoparticles were prepared by solvent/antisolvent precipitation method at different polymer:drug ratios of 1:1 and 2:1 using different polymers and grades of poly vinyl pyrolidone, hydroxy propyl methyl cellulose and sodium carboxymethyl cellulose as stabilizers. The effect of polymer type, ratio of polymer:drug, solvent:antisolvent ratio, stirring rate and stirring time on the particle size, were investigated and found to have a significant (p? 0.05) effect on particle size. The best formula was obtained with lowest average particle size of 84.05. This formula was studied for compatibility by FTIR and DSC, surface morphology by FESEM and crystalline state by XRPD. Then domperidone nanoparticles were formulated into a simple capsule dosage form in order to study of the in vitro release of drug from nanoparticles in comparison raw drug and mixture of polymer:drug ratios of 2:1. The release of domperidone from best formula was highly improved with a significant (p? 0.05) increase.

Study on Mechanical Properties of AA6061/SiC/B4C Hybrid Nano Metal Matrix Composites

2021 ◽  
Vol 1034 ◽  
pp. 35-42
Author(s):  
Shubhajit Das ◽  
M. Chandrasekaran ◽  
Sutanu Samanta
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Matrix Material ◽  
Average Particle Size ◽  
Volume Ratio ◽  
Casting Process ◽  
Hybrid Nanocomposites ◽  
Average Particle ◽  
Matrix Composites ◽  
Structural Applications

The present work investigates the mechanical characterization of aluminium alloy (AA) 6061 based hybrid nanometal matrix composites (MMCs) fabricated using conventional stir casting process. Two compositions viz., AA6061+1.5 wt.% B4C+0.5 wt.% SiC (Hybrid A) and AA6061+1.5 wt.% B4C+1.5 wt.% SiC (Hybrid B) was prepared and its mechanical properties such as microhardness, tensile, compressive, flexural and impact strength were investigated to compare with unreinforced AA6061. SiC and B4C ceramic particles (purity 99.89%) of average particle size of 50 nm were used as reinforcements. Significant enhancement in microhardness of 30.2% and 31.02% for hybrid A and B are observed respectively. The ultimate tensile strength (UTS) increased by 10.72% and 16.55% for hybrid A and B respectively. Improved interaction because of the enhanced surface to volume ratio at the interface resulted in improvement of mechanical properties. Field emission scanning electron microscopy (FESEM) of the fractured surface shows brittle fracture because of the incorporation of the ceramic reinforcements in the matrix material. The developed AA6061/SiC/B­4C hybrid nanocomposites show improved mechanical properties for high-performance structural applications.

Morphology-Controlled CaCO3 Nanostructures by Modified Co-Precipitation in Pulsed Mode

2015 ◽  
Vol 752-753 ◽  
pp. 148-153
Author(s):  
M.M. Nassar ◽  
Taha Ebrahiem Farrag ◽  
M.S. Mahmoud ◽  
Sayed Abdelmonem
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Rotation Speed ◽  
Average Particle Size ◽  
Calcium Nitrate ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray ◽  
Co Precipitation ◽  
Pulsed Mixing

Calcium carbonate nanoparticles and nanorods were synthesized by precipitation from saturated sodium carbonate and calcium nitrate aqueous solutions through co precipitation method. A new rout of synthesis was done by both using pulsed mixing method and controlling the addition of calcium nitrate. The effect of the agitation speed, and the temperature on particle size and morphology were investigated. Particles were characterized using X-ray Microanalysis, X-ray analysis (XRD) and scanning electron microscopy (SEM). The results indicated that increasing the mixer rotation speed from 3425 to 15900 (rpm) decreases the average particle size to 64±7 nm. A rapid nucleation then aggregation induced by excessive shear force phenomena could explain this observation. Moreover, by increasing the reaction temperature, the products were converted from nanoparticle to nanorods. The maximum attainable aspect ratio was 6.23 at temperature of 75°C and rotation speed of 3425. Generally, temperature raise promoted a significant homoepitaxial growth in one direction toward the formation of calcite nanorods. Overall, this study can open new avenues to control the morphology of the calcium carbonate nanostructures.

Evaluation of the Antimicrobial Activity of Citric Acid Functionalized Magnetite Nanoparticles

2020 ◽  
Vol EJMM29 (4) ◽  
pp. 143-149
Author(s):  
Ahmed M. El-Khawaga ◽  
Ayman A. Farrag ◽  
Ahmed I. El-Batal ◽  
Mohamed A. Elsayed
Keyword(s):  
Antimicrobial Activity ◽  
Citric Acid ◽  
Magnetite Nanoparticles ◽  
Pathogenic Bacteria ◽  
Average Particle Size ◽  
Maximum Activity ◽  
Precipitation Method ◽  
Average Particle ◽  
Effective Prevention ◽  
Fe3o4 Nps

Background: Antimicrobial resistance (AMR) has emerged as one of the principal public health problems of the 21st century that threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria no longer susceptible to the common medicines used to treat them. Objectives: To development of Fe3O4 NPs with specific sizes and shapes Potential as a new antibacterial agent. Methodology: In this study magnetite nanoparticles (Fe3O4 NPs) were synthesized through an aqueous co-precipitation method and functionalized with citric acid for outstanding their antimicrobial potential. Fe3O4 NPs were characterized by XRD, TEM, SEM, EDX and FTIR to analyze crystallinity, average particle size, morphology and functional groups, respectively. Antimicrobial activity was investigated against pathogenic bacteria as zone of inhibition (ZOI) and minimum inhibitory concentration (MIC). Results: Antimicrobial results showed that CA- Fe3O4 NPs owns maximum activity against Staphylococcus aureus and E. coli by 18.0 and 15.0mm ZOI, respectively. Conclusion: It should be noted that (CA-Fe3O4) NPs are also active upon Gram-positive than Gram- negative bacteria. The synthesized (CA-Fe3O4) NPs are promising for potential applications as antimicrobial agent and in drug delivery fields.

Synthesis and Characterization of Lysine Modified Chitosan Magnetic Microspheres: A Novel Gene Delivery System

2007 ◽  
Author(s):  
Shuangyan Li ◽  
Lijuan Hao ◽  
Yong Yang ◽  
Lei Han ◽  
Peng Yao ◽  
...  
Keyword(s):  
Single Photon ◽  
Average Particle Size ◽  
Photon Emission ◽  
Magnetic Microspheres ◽  
Gene Carrier ◽  
Precipitation Method ◽  
Emission Computed Tomography ◽  
Average Particle ◽  
Modified Chitosan ◽  
New Formulation

This paper describes a new formulation of magnetic nanoparticles coated by a novel polymer lysine modified chitosan (CS-lys) as gene carrier. Lysine modified chitosan was synthesized by performing carboxyl of lysine and amido of chitosan in the presence of 1-Ethyl-3-(3-dimethyllaminopropyl) carbodiimide hydrochloride (EDC). The absolute chemistry of the Lysine modified chitosan obtained were characterized using IR and 1H NMR, respectively. The results indicated that many amines of chitosan were modificatied with lysine, and optimized the correlation conditions. The lysine modified chitosan magnetic microspheres were preprated by co-precipitation method. The characterizations of microspheres were measured by TEM, XPS, Dynamic Laser Light Scattering, Vibrating Samples Magnetometer, and X-ray diffraction. The resultes indicated the average particle size was about 100nm and have good superparamagnetic property. The cytotoxicity of CS-lys MNPs was investigated with U293 cells. The results showed that the CS-lys MNPs retained of low toxicity; additionally, combination of DNA and CS-lys MNPs was observed from agarose gel electrophoresis, suggesting that the CS-lys MNPs could be a novel magnetic targeting gene carrier. We also studied the ability of complexes of CS-lys MNPs and DNA crossing BBB in rats by single photon emission computed tomography (SPECT).

Preparation of Nanosized Barium Titanate Powder by a Direct Reactive Precipitation Method

2013 ◽  
Vol 690-693 ◽  
pp. 454-457
Author(s):  
Hong Bo Li ◽  
Shu Yan Wu ◽  
Jing Wang ◽  
Chun Jie Li
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Surface Active Agent ◽  
Average Particle Size ◽  
Active Agent ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Average Particle ◽  
Powder Particle Size ◽  
Powder Morphology

Columnar crystaldendriteequiaxial dendritescolumnar crystalNanosized powder was synthesized by direct-reactive precipitation process using a stoichiometrical mixture of TiCl4, BaCl2 as the reactants while NaOH as precipitant. Under the ratio of Ba to Ti is 1.02, PH=13, three reaction temperature of 70°C, 80°C and 90°C were conducted respectively. Morphology and phase structure of powder were investigated, and the influence of reaction temperature on powder morphology was discussed. The result indicates that synthesized powder is single cubic BaTiO3 and contains no impurities. BaTiO3 powders generally show spherical, and average particle size decreases with increasing reaction temperature. When reaction temperature is 80°C, BaTiO3 powder has best uniformity and dispersivity with the diameter of 80-100nm. The influence of reaction temperature on powder particle size can be attributed to the corporate contribution of nucleation and growth rate. Polyglycol as surface active agent has a significant effect in restraining agglomeration.

Effect of Surfactant on the Preparation of Nano-powder for Yb Doping Laser Transparent YAG Ceramic

2013 ◽  
Vol 32 (5) ◽  
pp. 511-515 ◽  
Author(s):  
Xiao Guo Cao ◽  
Jia Wang ◽  
Qi Bai Wu ◽  
Hai Yan Zhang
Keyword(s):  
Particle Size ◽  
Polyethylene Glycol ◽  
Average Particle Size ◽  
Ammonium Bicarbonate ◽  
Spherical Particles ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Powder ◽  
Co Precipitation

AbstractYb:YAG transparent ceramic nano-powder was prepared by chemical co-precipitation method, with ammonium bicarbonate as the precipitant and polyethylene glycol as surfactant. The addition of polyethylene glycol can reduce the agglomeration and particle size of the prepared Yb:YAG powder. The morphology, thermal stability and phase structure of Yb:YAG nano-powder were charactered by scanning electron microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. The results show that well-crystallized nano-powder was obtained by calcining the precursors at 900 °C for 3 h. The average particle size of Yb:YAG powder is about 100–200 nm. When the volume amount of polyethylene glycol is 2.0%, well-dispersed Yb:YAG powder with spherical particles of 100 nm diameter was obtained.

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