Under the appearance of white feathers, sodium polyacrylate & potassium polyacrylate are both called "superabsorbent polymer". Both of them have powerful water-absorbent abilities.
| chemical name | sodium polyacrylate | potassium polyacrylate |
| usages | the absorbent material of diapers, sanitary napkins, etc. | water-retaining agent for plants |
| appearance of absorbing | white powder => white water gel => transparent water gel | white powder => transparent water gel |
| water-retaining ability of water gel | strong than roots of plants | weaker than roots of plants, strong than soil |
| decomposition time | in one week | more than two weeks |
| decomposition product | Na+, carbon dioxide, water, etc. | K+, carbon dioxide, water, etc. |
| price | low | high |
Sodium polyacrylate is widely used in every aspect of our life. And we can easily get sodium polyacrylate from paper diapers, sanitary napkins, etc.
Can we use sodium polyacrylate as a water-retaining agent for plants instead of potassium polyacrylate?
The answer is obviously no.
As sodium polyacrylate is much cheaper than potassium polyacrylate, some profiteers sell sodium polyacrylate as the water-retaining agent.
So we need to devise them before purchasing.
The simplest method is the sunlight test:
Expose the water gel to the sun, sodium polyacrylate (or low-quality potassium polyacrylate) water gel will melt in 7 days.