Published: Wednesday, 12 February 2020
Modified: Friday, 25 February 2022
How to measure nanobubbles?
Before evaluating how fine bubbles works, it is important to know what size distribution and which number concentration of fine bubbles you are using. When you notice it works, you should know the minimum required concentration and/or size distribution. This enables you to optimize generating fine bubbles not to waste the time of generation and minimize the system size. On the other hand, there are applications which require higher concentration than 100M/ml and you cannot tell there is no effect by using Ultrafine bubbles generating machine which makes 50M/ml concentration.
We need to be careful enough about fine bubbles concentration. Fine bubbles can be measured by the same technology of measuring small particles. You can measure MB by camera (count pixel size) or laser (count blackout time), also as a simple method to know number index, you can refer information of turbidity.
When you measure UFB, most common way is to analyze Brownian Motion. Use laser and microscope to catch scattered light from UFB, take video and analyze how fast each UFB moves. (It is called Particle Tracking Analysis =PTA). As you know, Brownian Motion Speed is not depended on the type of material but only by size, liquid temp. and viscosity of liquid. You know liquid temp and viscosity so fast Brownian motion means small Ultrafine bubbles and slow one means relatively bigger Ultrafine bubbles. By tracking the Brownian motion, you will know the size of each Ultrafine bubbles.
ALT Ultrafine bubble sensor
NanoSight with the particle tracking analysis method is probably the most widely used measurement instrument for ultrafine bubbles. But also, Shimadzu with the Sald7100HH and the Helos from Sympatec can measure ultrafine bubbles. The downside of this equipment is that it's relatively expensive and not suitable for process monitoring. Many clients are looking for a more economical solution to get an indication if their ultrafine bubble generator is working perfectly and to safe costs and energy when high levels of ultrafine bubbles are reached equipment should stop automatically. The ALT-9F17 is an ultrafine bubble sensor system based on the scattered laser principle.