ISO/NP 24218-2

Fine bubble technology — Characterization of fine bubbles — Part 2: Evaluation of size and concentration by multi-wavelength light extinction method

Scope

This document specifies requirements for multi-wavelength light extinction methods for determining the size distributions and concentrations of bubbles dispersed in transparent liquid media, mostly in water. Ultrafine bubbles, particularly from 100 nanometers to 1 micrometer are within the scope of this document. Under special conditions, the upper and lower limits of measurement can be respectively extended to 50 nanometers and 10 micrometers with extending wavelength ranges. The number concentration range spans from 1×106 to 1×1010 bubbles/mL depending on the bubble size and measurement system or optical path length, and accordingly, the volume concentration ranges from 10⁻⁸ to 10⁻⁴. In addition, the online measurement capability of multi-wavelength light extinction methods enables real-time monitoring and continuous analysis, which offers significant advantages for process control in industrial applications, reduces sampling errors, enhances efficiency, and enables immediate feedback for system optimization.