Functionalized galactoglucomannan-based hydrogels for the removal of metal cations from aqueous solutions

New types of hydrogels derived from O-acetyl galactoglucomannan (AcGGM) hemicellulose have been synthesized and characterized. The objective of this work was to analyze the sorption capacity (S) of three types of hydrogels containing AcGGM derivatives incorporated into the carboxylic groups of the polymer chain in the AA hydrogel, sulfonic groups in the APA hydrogel, and amide groups in the acrylamide (Aam) hydrogel. These hydrogels are capable of interacting and removing ions such as cadmium [Cd(II)], copper [Cu(II)], lead [Pb(II)], nickel [Ni(II)], and zinc [Zn(II)]. The results show that AA and Aam hydrogels had a lower sorption capacity of ions compared to the APA hydrogel, which had a high sorption capacity. The maximal sorption capacity was determined by the successive enrichment method, obtaining Pb(II) amount of 48.3 mg/g of AA hydrogel, 65.8 mg/g of APA hydrogel, and 40.8 mg/g of Aam hydrogel. Hence, Pb(II) ions are greatly retained by the three hydrogels. These results are promising for the development of new materials with potential applications in metal ion removal.