Electrostatic Spray Dispersion Method for Metal Nanoparticles
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Solution Overview
Problem
Current methods for producing metal nanoparticles struggle with precise control of particle diameters, distribution, and shape, leading to inefficiencies in synthesis and low recovery rates due to clogged microreactors and inefficient droplet collisions in electrostatic sprays.
Innovation Solution
A method and apparatus utilizing electrostatic spraying with a low dielectric liquid and a second liquid, where the first substance is sprayed from a nozzle with an electrode, allowing for precise control of droplet sizes and reaction product distribution, enhancing mixing efficiency and reducing self-assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a microreactor is used to mix chloroauric acid solution and reducing agent, then mixing speed increases and volume of reaction solution to be mixed decreases, but the inner diameter of tubular flow paths becomes too small causing reaction product to adhere to walls and clog the microreactor
Solution Approach 1:
The invention divides the reaction system into two separate phases: a low dielectric liquid phase containing the metal salt solution and an aqueous phase containing the reducing agent. The spray nozzle is positioned in the low dielectric liquid phase, spraying droplets into the aqueous phase. This segmentation allows the reaction to occur in the aqueous phase while the low dielectric liquid phase acts as a reservoir, preventing clogging of the spray port and tubular flow paths.
Solution Approach 2:
The low dielectric liquid serves as an intermediary medium between the spray nozzle and the reaction zone. It allows the metal salt solution to be stored and transported without direct contact with the spray port, while still enabling the droplets to be sprayed into the aqueous phase where the actual reduction reaction occurs. This intermediary phase prevents adhesion of reaction products to the spray port and microreactor walls.
2Manufacturing precision
If electrostatic spraying is used to mix metal salt solution and reducing agent, then droplet sizes can be controlled and mixing efficiency increases, but self-assembly of metal nanoparticles occurs and recovery rate decreases
Solution Approach 1:
The invention creates different local environments for the metal salt solution and reducing agent. The metal salt solution is dissolved in a low dielectric liquid with specific properties (dielectric constant of 2.2 or less), while the reducing agent is in the aqueous phase. This local differentiation prevents premature self-assembly by controlling the chemical environment, allowing precise control of droplet sizes during spraying while maintaining nanoparticle stability and improving recovery rates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-speed and highly efficient production of metal nanoparticles with desired properties by controlling droplet sizes and reaction conditions, improving synthesis efficiency and recovery rates.
Implementation Method 1
droplets of the first liquid in which the first substance is dissolved or dispersed, are electrostatically sprayed from the spray port of the nozzle, the droplets being charged by generating a potential difference between the nozzle and the electrode
Implementation Method 2
A phase of the second liquid and a phase of the low dielectric liquid are arranged one on top the other in such a manner that the two phases are separated from each other
Data Source
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AI summary
A method and an apparatus for producing a dispersion, which enable high-speed and highly-efficient production of a dispersion of a reaction product having desired properties, are provided. The present invention relates to such a method and an apparatus for producing a dispersion. In the method and the apparatus, a first substance is dissolved or dispersed in a first liquid, a second substance is dissolved or dispersed in a second liquid or a low dielectric liquid, a phase of the second liquid and a phase of the low dielectric liquid are one on top of the other in such a manner that the two phases are separated from each other, a spray port of a nozzle is disposed in the low dielectric liquid phase, or is disposed at a position apart from the two phases but close to the low dielectric liquid phase in such a manner that the spray port is oriented to a liquid surface of the low dielectric liquid phase, and an electrode is disposed in the second liquid phase. In these states, droplets of the first liquid in which the first substance is dissolved or dispersed, are charged by generating a potential difference between the nozzle and the electrode, and are electrostatically sprayed from the spray port of the nozzle. In the method and the apparatus, the first liquid which was electrostatically sprayed, passes through the phase of the low dielectric liquid and reaches the phase of the second liquid so that the reaction product is dispersed in the second liquid phase or in the low dielectric liquid phase.