**Author details**

In **Figure 8**, the heavy metal ions removal capacity (mg amount of sorption Pb2+ per unit mass)

and poly(AAm-co-AAc)/pectin (a) hydrogels with 1% (2), 2% (3), 3% (4), and 4% (5) pectin and poly(AAm-co-AAc)/

unit dry mass of the gel. Adsorption of heavy metal ions occurs due to ionic and coordination

At first, complexation takes place mainly on the surface of the hydrogel, as evidenced by the high initial rate of sorption of metal ions, possible to observe inhomogeneous distribution of ionic groups, which leads to uneven swelling of the hydrogel by volume. The experimental results show that the hydrogel-filled composites filled with pectin have greater sorption ability than the unfilled hydrogel (**Figure 8a**). The increase in the sorption of lead ions by pectin-containing hydrogels is via additional complex formation due to the presence of a large number of free carboxyl groups in the pectin molecules. Thus, from a solution with a concentration of 0.1 M lead nitrate, composites with 1 and 3% pectin are adsorbed by 20% of lead ions more than the uncharged hydrogel. However, as **Figure 8b** shows, hydrogels containing bentonite absorb a larger amount of lead ions. Moreover, the sorption capacity of bentonite-containing hydrogels is 25% higher than that of polysaccharide-containing hydro-

Nowadays, there is a trend in development of multifunctional nanocomposites based on different types of hydrogels acting as a matrix for various nanomaterials. Crosslinked hydrophilic polymers are capable of absorbing large volumes of waters and salt solutions. Therefore, most of the modern work is devoted to the development of new composite materials based on

)2

poly(AAm-co-AAc) hydrogel (1)

)2

sorbed onto

of the hydrogel systems is increased with the increasing concentration Pb(NO3

interactions with charged hydrogel groups (chemisorption).

bentonite (b) hydrogels with 1% (2), 2% (3), 3% (4), and 4% (5) bentonite.

**Figure 8.** Sorption of lead ions from solutions of various concentrations of Pb(NO3

gels (as moisture absorbing properties).

hydrogels with improved sorption properties.

**4. Conclusion**

110 Recent Research in Polymerization

Mayya V. Uspenskaya, Vera E. Sitnikova, Michael A. Dovbeta, Roman O. Olekhnovich and Igor Yu. Denisyuk\*

\*Address all correspondence to: denisiuk@mail.ifmo.ru

Department of IT in Fuel and Energy Industry, ITMO University, St. Petersburg, Russia
