scholarly journals Continuous Flow Controlled Synthesis of Gold Nanoparticles Using Pulsed Mixing Microfluidic System

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Guojun Liu ◽  
Xuhao Yang ◽  
Yan Li ◽  
Zhigang Yang ◽  
Wen Hong ◽  
...  

To prepare the gold nanoparticles (AuNPs) with uniform sizes, fine morphology, and good monodispersity, a pulsed mixing microfluidic system based on PZT actuation was presented. The system includes PZT micropump and Y type micromixer. By adjusting voltage (entrance flow rate), pulsed frequency, phase, and other parameters, a variety of mixing modes can be achieved, so as to realize the controllable synthesis of nanoparticles in a certain range. By numerical simulation and analysis, the channel section size, entrance angle, and pulse frequency were optimized. Based on the optimized structure and working parameters, the test prototype has been manufactured in lab, and the related synthesis tests of AuNPs were carried out. The test results indicate that AuNPs with uniform morphology and good monodispersity can be synthesized using the system with the section size (0.4 mm × 0.4 mm), the entrance channel angle (60°) under condition of the pulsed frequency (300 Hz), and the entrance flow rate (4 mL/min). The average diameter and its standard deviation of AuNPs synthesized were 21.6 nm, 4.83 nm, respectively. The research work above can be applied to the fields such as the controlled synthesis of noble metal nanoparticles, biomedicine, and microchemical system.

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1995
Author(s):  
Yunjia Wang ◽  
Shunxiang Liu ◽  
Feng Zhu ◽  
Yiyu Gan ◽  
Qiao Wen

In recent years, the transition metal carbonitrides(MXenes) have been widely applied to photoelectric field, and better performance of these applications was achieved via MXene complex structures. In our work, we proposed a MXene core-shell nanosheet composed of a Ti2C (MXene) phase and gold nanoparticles, and applied it to mode-locked and single-frequency fiber laser applications. The optoelectronic results suggested that the performances of these two applications were both improved when MXene core-shell nanosheets were applied. As a result, we obtained a mode-locking operation with 670 fs pulses, and the threshold pump power reached to as low as 20 mW. Besides, a single-frequency laser with the narrowest linewidth of ~1 kHz is also demonstrated experimentally. Our research work proved that MXene core-shell nanosheets could be used as saturable absorbers (SAs) to promote versatile photonic applications.


2015 ◽  
Vol 812 ◽  
pp. 112-117
Author(s):  
K.M. Kumar ◽  
P. Venkateswaran ◽  
P. Suresh

The coolant (water) pump assumes an important role of cooling system in IC engines. With upgrading of the engine power by turbocharging and turbo inter cooling, the water pump capacity needs to be increased corresponding to the power. This capacity enhancement has to be achieved without calling for a major change in the existing water pump, envelop and related fitment details. This requires a clear understanding of centrifugal pump for its performance parameter. One such engine is upgraded by turbocharging from 195PS to 240PS @2200 rpm. Improving water pump flow by changing the impeller dimensions, impeller casing, increase the suction, delivery pipe diameter had been done. Validation of the water pump in its actual engine installation was taken up as a part of the research work. Flow rate comparison of the new pump with the existing pump was made and the results were analyzed. The new water pump gives better flow rates for the engine speeds up to1800 rpm, beyond which the flow rate is slightly lesser than the existing pump.


2019 ◽  
Vol 8 (4) ◽  
pp. 3054-3058

The rise of atmospheric carbon dioxide (CO2 )concentration as well as depletion of fossil fuel reserves calls for the development of clean and ecofriendly alternative fuel source. Recently, lipid rich microalgal biomass is being extensively studied for generation of biodiesel however, the expensesincurred on production of microalgal biomassis a significant hurdle. Almost 80 % of the production costis generated from the cultivation medium which majorly comprise of carbon, nitrogen and phosphate. If the microalgal cultivation could be linked to a CO2 capturing unit than the cost of production could be reduced to a large extent. CO2 absorption by means of aqueous amine solvents is known to be a mature technology and could be integrated with microalgal cultivation unit for efficient utilization of the captured CO2 . In this present research work, blended solution of piperazine (PZ) and2-amino2-methyl-1-propanol (AMP) (5/25 wt. %) was used to capture CO2 and then the captured CO2 was utilized as an inorganic carbon stream for growing Chlorella sorokiniana BTA 9031 for biodiesel production. The CO2rate absorption was governed by series of process variablesviz.solvent flow rate ranges (1.5 to 3) ×10⁻4 m 3 min-1 , absorption temperature (298 to 313) K,concentration of CO2 (10 to 15) kPa and gas flow rate(5 to 8) ×10⁻3 m 3 min-1 . The detected final biomass strengthofChlorella sorokiniana BTA 9031 was0.955g L-1 . The fatty acid methyl esters (FAME) determinedsubsequentlyacid transesterification was observed to contain fatty acids suitable for biodiesel production.


Author(s):  
SAUD BAWAZEER

Objective: The main objective of the current research work was synthesized of gold nanoparticles (AuNPs) of Thevetia peruviana aqueous extract,characterization, and screening for urease enzyme inhibitory activity.Methods: AuNPs were synthesized by mixing 1 mM gold salt solution with T. peruviana aqueous extract without any reducing agents. The preparedAuNPs were characterized using UV–visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques. Thesynthesized AuNPs were assessed for in vitro urease enzyme inhibitory activity at 0.2 μg in comparison with the aqueous extract.Results: In this finding, we synthesized the AuNPs of T. peruviana aqueous extract for the 1st time. The AuNPs exhibited significant stability atroom temperature. The AuNPs showed significant urease inhibitory activity with IC50 67.56±1.67 at 0.2 μg as compared to aqueous extract whichexhibited good activity with IC50 39.21±1.32 μ at 0.2 mg, against standard thiourea (IC50=21.00±1.16). The formation of AuNPs correlates due to activephytochemical present in extract which is responsible for synthesizing NPs.Conclusion: T. peruviana extract and prepared AuNPs are an outstanding urease enzyme inhibitor and are capable of making fine NPs. Application:The synthesized AuNPs of T. peruviana aqueous extract which significant urease inhibitory activity may allow us to discover NPs for potentiallyeffective and safe nanoherbal therapy.


2020 ◽  
Vol 5 (2) ◽  
pp. 356-366 ◽  
Author(s):  
Edith Chow ◽  
Burkhard Raguse ◽  
Enrico Della Gaspera ◽  
Steven J. Barrow ◽  
Jungmi Hong ◽  
...  

4-Dimethylaminopyridine-stabilised gold nanoparticles are synthesised in a biphasic flow reactor system using organic/aqueous membrane separators and gas-permeable tubing.


2019 ◽  
Vol 10 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Xudong Zhang ◽  
Su Ma ◽  
Aikun Li ◽  
Linya Chen ◽  
Jiangwei Lu ◽  
...  

2016 ◽  
Vol 186 ◽  
pp. 77-93 ◽  
Author(s):  
Yon Ju-Nam ◽  
Wanisa Abdussalam-Mohammed ◽  
Jesus J. Ojeda

In this work, we report the synthesis of novel cationic phosphonium gold nanoparticles dispersible in water and dimethyl sulfoxide (DMSO) for their potential use in biomedical applications. All the cationic-functionalising ligands currently reported in the literature are ammonium-based species. Here, the synthesis and characterisation of an alternative system, based on phosphonioalkylthiosulfate zwitterions and phosphonioalkylthioacetate were carried out. We have also demonstrated that our phosphonioalkylthiosulfate zwitterions readily disproportionate into phosphonioalkylthiolates in situ during the synthesis of gold nanoparticles produced by the borohydride reduction of gold(iii) salts. The synthesis of the cationic gold nanoparticles using these phosphonium ligands was carried out in water and DMSO. UV-visible spectroscopic and TEM studies have shown that the phosphonioalkylthiolates bind to the surface of gold nanoparticles which are typically around 10 nm in diameter. The resulting cationic-functionalised gold nanoparticles are dispersible in aqueous media and in DMSO, which is the only organic solvent approved by the U.S. Food and Drug Administration (FDA) for drug carrier tests. This indicates their potential future use in biological applications. This work shows the synthesis of a new family of phosphonium-based ligands, which behave as cationic masked thiolate ligands in the functionalisation of gold nanoparticles. These highly stable colloidal cationic phosphonium gold nanoparticles dispersed in water and DMSO can offer a great opportunity for the design of novel biorecognition and drug delivery systems.


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