How to detect polyaluminium chloride?

Steps for detecting polyaluminium chloride:

1. Weigh about 2.5G (about 0.0002g) of solid polyaluminium chloride sample, put it into a 250ml beaker (add an appropriate amount of water to the beaker first), completely dissolve it, completely transfer it into a 250ml volumetric flask, dilute it to the scale, shake it well and dry filter it (medium speed qualitative filter paper, conical flask and funnel used for filtration are dried). The filtered liquid is called test solution a.

2. Take 10ml of filtered liquid into a conical flask (add it with a pipette), add 10ml of nitric acid (add it with a pipette), heat it for 1 minute, remove it, flush it with distilled water, add 20ml of EDTA (add it with a pipette), add 2 drops of thymol blue, and adjust it to yellow with ammonia (the hot drop does not need to be cooled).

3. Heat for 2 minutes, cool, add 10ml sodium acetate buffer solution (added by automatic liquid adding tube), add 3 drops of xylenol orange, and drop it to red with zinc acetate standard solution. Polyaluminium chloride testing is required. It is recommended to find a formal third-party testing organization. The scientific standard testing is very good.