Synergistic Improvement of Mechanical and Adsorption Properties by Constructing Physical Multiple-Network Hydrogel for Removing Uranium

Biomass hydrogels, a kind of favorable adsorbents, have been applied extensively in uranium removal due to its three-dimensional network structure. However, it usually can not maintain good mechanical properties and adsorption properties simultaneously. Furthermore, chemical hydrogels, due to the usage of hazardous chemical crosslinkers and initiators, would inevitably result in secondary environmental pollution during its preparation. To improve the poor mechanical property of biomass polymer gellen gum (GG) as an adsorbent, while maintaining its good adsorption capacity, a multiple -network hydrogel (GG-CS-Ca) was physicallly constructed by self -assembly using GG and another cationic polyelectrolyte chitosan (CS) together with Ca2+ in this work. The structure, morphology and stability were disclosed by FTIR, SEM, EDS, XPS and TG analysis. Furthermore, its adsorption properties were systematically investigated by static and dynamic adsorption testing. The results indicated that the mechanical strength of GG-CS-Ca was improved compared with as -prepared adsorbent GG-Ca while its adsorption capacity maintained at a higher level which was twice of the mechanically reinforcing GGbased adsorbent GG-CMKGM. It indeed achieved the synergistic improvement of mechanical strength and adsorption capacity. Moreover, it showed favorable acid -resistant stability because of the electrostatic crosslinking of negative GG and positive CS under high acidic condition. The dynamic adsorption analysis certified that it could be applied in actual uranium removing as an adsorbent and the application parameter could be predicted by Thomas and Yoon-Nelson model.