ISO/TC 281/WG 2 - Fine bubble characterization and measurement

This document specifies the evaluation of fine bubbles size and concentration indices applied to the combined use of number-based size analysis and volume-based size analysis by the laser diffraction method. The methodology described is appropriate to both bimodal and multimodal samples over a broad size range (from tens of nanometers to tens of micrometers) and applies to ultrafine bubble and microbubble dispersions (MBD) and mixtures thereof.

This document specifies the elimination techniques for removing fine bubbles from fine bubble dispersion in water and how to optimize the elimination procedures to obtain better efficiency. This document is applicable to fine uncoated bubbles (without shells). It does not apply to fine coated bubbles (with shells). NOTE Fine bubbles dispersed in liquid are classified into “fine bubble with shells” and “fine bubble without shells”. Fine bubble with shells means the fine bubble whose surface/interface is covered almost completely by an object or a collection of objects.

This document specifies the evaluation procedure of fine bubble elimination for fine bubble dispersion in water. This document is applicable only to fine bubbles without shell.

This document focuses on listing most commonly used preparation and characterization techniques for fine bubbles and their interpretation. The merits and limitations of each of the techniques are outlined.

This document specifies the evaluation method for the size index of microbubbles in microbubble dispersion. It is only applicable to microbubbles with or without shell in water within the range from 1 μm to 100 μm. It describes the sampling methods from the point generating or dispersing microbubbles in the retention container to the detecting point of the measuring instruments.

This document specifies procedures and requirements for sampling and sample preparation of ultrafine bubble dispersions in water. This document is applicable to relatively stable dispersions where the size and number of bubbles are relatively constant for the duration of the sampling, sample preparation and measurement. This document is not applicable to less stable fine bubble dispersions or microbubble dispersions.

This document describes the procedures and equipment for storage and transportation of ultrafine bubble dispersions in water and specifies the related requirements in order to maintain such bubble characteristics as size and number concentration.