|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|
|the 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.|
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 a 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.