The new methods mainly contain the adsorption of natural materials, modification materials, humic acids, biosorption, quod of silicon micro encapsulization and nanotechnology.
Humic acid is a kind of organic matter with high molecular quantity and satisfactory biological activity, and there are abundant humic acid in airslake-coal.
Humic acid (HA ) was abstracted from leonardite,and a composite superabsorbent (HA PSA ) was prepared by compounding poly (acrylic acid ) and lignitic humic acid.