Gellan gum-alginate/PVA-co-PAM crosslinked hydrogel for phenol adsorption: Fabrication, characterization, and
Gaurav Sharma1, Yaksha Verma2, Pooja Dhiman2
1International Research Centre of Nanotechnology for Himalayan Sustainability (IRCNHS), Shoolini University, Solan, 173229, India; Institute for Interdisciplinary and Innovation Research, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China.
Abstract:
This study explores the synthesis, characterization, and application of a Gellan Gum/Sodium Alginate-based Poly (vinyl alcohol)-co-Polyacrylamide Cross-Linked (GG/SA-PVA-co-PAM-CL) hydrogel for phenol removal. The hydrogel was synthesised through free radical graft copolymerization with N, N'-methylene-bis-acrylamide as the crosslinker. It exhibited excellent swelling ability and structural stability. FTIR analysis confirmed the presence of functional groups, including carboxyl (1601.92 cm-1), hydroxyl (3218.10 cm-1), and amide (613.40 cm-1), supporting successful polymer integration, while XRD revealed a combination of crystalline and amorphous regions. FESEM and EDX confirmed a porous morphology with uniform elemental distribution, and TGA demonstrated good thermal stability. Adsorption studies indicated an optimal phenol uptake capacity of 78.0 mg/g at pH 6 with phenol concentration of 50 ppm at 25 °C, following the Sips isotherm and pseudo-second-order kinetics, with thermodynamic analysis suggesting an exothermic process. The hydrogel retained more than 75% adsorption efficiency after five regeneration cycles. These findings demonstrate that the GG/SA-PVA-co-PAM-CL hydrogel is a promising and reusable material for efficient phenol removal from wastewater.
