Adsorption of lead ions by a kind of MAL modified hydrogel beads

Hydrogel-I was fabricated via sodium alginate in situ-embedding with MAL powders and then applied to decontaminating Pb(II) from water. Conditions for preparing Hydrogel-I and the adsorption of Pb(II) over Hydrogel-I were optimized through response surface methodology coupled with central composite design. XPS revealed that the groups of —OH, —COO—, —NH, —NH2 and —CSS— carried by Hydrogel-I were responsible for the uptake of Pb(II). Ions exchange, surface complexation, electrostatic attraction and pore-filling effect contributed to the adsorption process. Adsorption performances of Pb(II) by Hydrogel-I and MAL powders were compared. Although they exhibited similar adsorption rate and maximum adsorption capacity (qm), the reusing ability of Hydrogel-I was better and it was easier to be separated from aqueous solution after treatment. Even compared with organic hydrogel materials, Hydrogel-I presented relatively quick adsorption speed and high adsorption capacity. It can be concluded that Hydrogel-I could be an alternative scavenger for the treatment of Pb(II) from aqueous solution.