The water-insoluble content of polyaluminum chloride (PAC) can be determined by the following steps:
Take a certain amount of polyaluminum chloride solution (generally 100 mL), and filter it with a filter paper funnel.
The filtered residue was repeatedly washed with deionized water until no chloride ions were detected in the washing solution.
Dry the filter paper and residue at 105°C to constant weight, and weigh the filter paper and residue.
Water-insoluble content (%) = (weight of filter paper and residue - weight of filter paper) / sampling amount (g) × 100%.
It is worth noting that in order to reduce errors, the filtration operation should be carried out under the same conditions, such as the type, thickness and filtration speed of filter paper should be consistent.