What Ultrasonic Sonochemical Equipment Can Be Used For?
When a liquid is treated with high-intensity ultrasound, the sound waves propagating into the liquid medium create alternating cycles of high pressure (compression) and low pressure (sparse), the rate of which depends on the frequency. During low-pressure cycling, high-intensity ultrasonic waves create small vacuum bubbles or voids in the liquid. When the bubbles reach a volume where they can no longer absorb energy, they collapse violently during high-pressure cycling, a phenomenon known as "cavitation." During the explosion, very high temperatures (about 5,000K) and pressures (about 2,000 atm) will be reached locally. The collapse of the cavitation bubbles also results in a liquid jet with a velocity of up to 280 m/s, and the resulting shear force mechanically stirs the liquid to thoroughly mix the reactants.
Therefore, with the cavitation effect of ultrasonic waves in liquids, ultrasonic sonochemical equipment can be applied to extraction, crushing, mixing, emulsification, dispersion, stirring, defoaming and degassing, and accelerating reactions.
Ultrasonic dispersion is based on liquid as the medium, and high-frequency ultrasonic vibration is added to the liquid. Since ultrasound is a mechanical wave, it is not absorbed by molecules and causes vibrational motion of molecules during propagation. Under the cavitation effect, that is, under the additional effects of high temperature, high pressure, micro-jet, and strong vibration, the distance between molecules increases their average distance due to vibration, which eventually leads to molecular fragmentation. The instantaneous pressure released by the ultrasound breaks the van der Waals forces between the particles, making it less likely that the particles will agglomerate together. Compared with conventional dispersion methods, ultrasonic dispersion technology has high efficiency and short time. There are applications in the manufacture of graphene, nanomaterials, oils and paints.
Under the action of ultrasonic energy, two or more immiscible liquids are mixed together, and one liquid is uniformly dispersed in the other liquid to form an emulsion-like liquid. This process is called ultrasonic emulsification. The biggest feature of ultrasonic emulsification is that no emulsifier is required. In addition, ultrasonic emulsification can control the type of emulsion, the formed emulsion is more stable, and some are stable for several months to more than half a year; the prepared emulsion has a high concentration, the concentration of pure emulsion can exceed 30%, and the added emulsifier can reach 70%; Phacoemulsification can also prepare emulsions that cannot be prepared by conventional methods. For example, the common mixing method can only produce a 5% paraffin emulsion in water, while it is incredible that a 20% paraffin emulsion can be produced under the action of a powered ultrasonic field. The emulsification ability of ultrasonic emulsification equipment in the laboratory has been well known and used for a long time, and it is used in the industry for high-efficiency emulsification of mass production in production plants, such as cosmetics and skin care products, pharmaceutical ointments, paints, lubricants and fuel etc.
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