Ultrasonic homogenization is a technique that utilizes the physical effects generated by high-frequency ultrasonic vibration to treat liquid or semi fluid materials. Its core function is to break down particles, droplets or aggregates in materials through the effects of "cavitation effect", "mechanical shear", "turbulent disturbance" induced by ultrasound, achieving material refinement, dispersion, mixing, emulsification or cell breakage, and ultimately obtaining a system with uniform composition and high stability.
It is widely used in various fields such as food industry, biomedicine, materials science, cosmetics, etc., and is a key technology for achieving micro homogenization of materials.
1、 Core working principle: How can ultrasound achieve "homogenization"?
The core driving force of ultrasonic homogenization is cavitation effect, which, together with mechanical shear and turbulence, completes the refinement and homogenization of materials. The specific process can be divided into three steps:
Formation of cavitation bubbles: The ultrasonic generator generates high-frequency sound waves ranging from 15kHz to 1MHz, which are transmitted into the material through a probe (ultrasonic amplitude rod). The alternating compression and stretching of sound waves will form a large number of tiny "cavitation bubbles" (tiny bubbles filled with gas or steam) in liquids.
Growth and collapse of cavitation bubbles: With the vibration of sound waves, cavitation bubbles continuously expand during the stretching stage and rapidly collapse during the compression stage (with a lifespan of only a few microseconds). The moment of collapse will generate extreme physical conditions locally:
Localized high temperature (up to 5000K), high pressure (up to 100MPa);
Intense micro jets (with speeds up to 100m/s) and shock waves;
Intense turbulence and shear forces.
Material homogenization: These extreme conditions will directly affect particles, droplets, or cells in the material:
Break the agglomeration of solid particles (such as the dispersion of nano powder in liquid);
Tearing droplets in liquid (such as emulsification of oil phase in water phase);
Penetrating the cell wall of cells (such as the breakdown of bacteria and plant cells), ultimately forming a uniformly dispersed system of materials.
2、 Main application scenarios: What can ultrasonic homogenization do?
The application of ultrasonic homogenization covers multiple industries, with the core being to solve problems such as "uneven material distribution", "oversized particles", and "difficult dispersion". The specific scenarios are as follows:
1. Biomedical field: Cell lysis and component extraction
This is one of the classic applications of ultrasonic homogenization, mainly used for extracting active ingredients from cells.
Cell fragmentation: The impact and shear forces generated by cavitation effect penetrate the cell walls of bacteria, yeast, and plant cells (such as algae and traditional Chinese medicine cells), releasing active substances such as proteins, enzymes, nucleic acids, polysaccharides, etc. inside the cells.
Example: Extracting recombinant proteins from Escherichia coli in the laboratory, extracting Ganoderma polysaccharides from Ganoderma spores, and extracting chlorophyll from algae.
Homogenization of formulations: Used for preparing nano drug carriers (such as liposomes and nanoparticles), refining droplets to make drug dispersion more uniform, enhancing drug solubility and bioavailability.
Example: Preparation of nano formulations of anticancer drugs, reducing drug particle size and enhancing tumor tissue penetration.
2. Food and beverage industry: emulsification, dispersion, and quality optimization
Used to improve the taste, stability, and nutritional value of food, avoiding problems such as layering and sedimentation.
Emulsification treatment: Mixing immiscible liquids (such as oil and water) into a stable emulsion.
Example: Making salad dressing (emulsified in oil and water phases), plant-based protein drinks (such as soy milk to avoid protein particle precipitation), ice cream (refining fat globules to enhance delicate taste).
Dispersion processing: Breaking the agglomeration of powder materials in liquid to achieve uniform dispersion.
Example: Chocolate sauce (refine cocoa powder particles to avoid clumping), fruit juice (disperse fruit pulp particles to improve taste uniformity), nutritional supplements (such as protein powder, liquid dispersion of probiotics).
Sterilization assistance: The high temperature and high pressure generated by cavitation effect can assist in killing some microorganisms (such as bacteria and mold), and improve food safety with traditional sterilization processes (not the main sterilization method, mostly auxiliary).
3. Materials science field: Preparation and dispersion of nanomaterials
It is used to prepare or treat nanometer materials to solve the problem of easy agglomeration of nanometer powders.
Dispersion of nano powders: disperse carbon nanotubes, graphene, nano titanium dioxide and other nano powders into water or organic solvents to form a stable dispersion (to avoid performance degradation caused by agglomeration).
Example: Preparation of graphene conductive paste (uniform dispersion is necessary to ensure conductivity), nano coating (refining pigment particles to improve coating flatness and corrosion resistance).
Nanomaterial synthesis: Through extreme conditions of cavitation effect, chemical reactions are induced to generate nanoparticles (such as nano metal particles, quantum dots), with more uniform particle size and controllable particle size.
4. Cosmetics and daily chemicals: lotion preparation and texture optimization
The lotion and face cream in cosmetics are mostly emulsion systems. Ultrasonic homogenization can improve the stability and sense of use of products.
Lotion preparation: oil phase (such as mineral oil, vegetable oil) and water phase (such as glycerin, water) are emulsified to form a stable lotion, avoiding stratification.
Example: face cream (refine oil particles to make the texture more delicate and easy to absorb), sunscreen (disperse sunscreen particles to improve sunscreen effect and skin feel).
Active ingredient dispersion: Evenly disperse active ingredients such as vitamin C and niacinamide into the base material to ensure consistency in product efficacy.
5. Environmental engineering field: wastewater treatment and degradation
Utilize the cavitation effect of ultrasound to degrade pollutants or pretreat sludge.
Organic pollutant degradation: The hydroxyl radicals (· OH) generated by the collapse of cavitation bubbles have strong oxidizing properties and can degrade difficult to degrade organic compounds in wastewater, such as pesticides, dyes, and petroleum pollutants.
Sludge pretreatment: Crushing microbial cells in sludge, releasing intracellular water, reducing sludge moisture content, and facilitating subsequent dewatering treatment.