Today, I saw someone dissolve yellow powder and pour it into the river, saying it was clean river water. What powder is it?
It should be polyaluminum chloride, which is a commonly used water purifying agent.
Polyaluminum chloride is hydrolyzed in water to produce * * * polymers such as Al(OH)3 and Al(OH)2Cl. * * * Polymer has a large surface area and can adsorb, coagulate and precipitate pollutants.