Synthesis and characterisation of zinc oxide modified biorenewable polysaccharides based sustainable hydrogel nanocomposite for Hg2+ ion removal: Towards a circular bioeconomy

Industrial metal ion pollution has been considered the chief source of water contaminants all over the world. In the present research, we have prepared gum tragacanth cross-linked 2-hydroxyethyl methacrylate-co-acrylamide (GT-cl-(HEMA-co-AAm)) hydrogel and gum tragacanth cross-linked 2-hydroxyethyl methacrylate-co-acrylamide/zinc oxide (GT-cl-(HEMA-co-AAm)/ZnO) hydrogel composite with better Hg2+ adsorption capability. GT-cl-(HEMA-co-AAm)/ZnO hydrogel composite (154.8 mg g-1) exhibited higher Hg2+ adsorption than GT-cl-(HEMA-co-AAm) hydrogel. To address the performance of GT-cl-(HEMA-co-AAm) hydrogel and GT-cl-(HEMA-co-AAm)/ZnO hydrogel composite, batch adsorption experiments were successfully conducted under different optimised conditions. At last, in-vitro antibacterial activities of Hg2+ loaded GT-cl-(HEMA-co-AAm) and GT-cl-(HEMA-co-AAm)/ZnO were performed in two different well Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative) bacteria. As a positive control, ampicillin was employed against both types of bacteria. This methodology for the reusability of material has a great ecofriendly impression for minimising secondary waste derived from adsorption and can help design upgraded antibacterial agents.