DOI: https://doi.org/10.55373/mjchem.v24i4.215

Keywords: Interpenetrating polymer networks, adsorbents; adsorption, organic dyes, methylene blue, methyl orange

Abstract

Superabsorbent interpenetrating polymer networks (IPN) consisting of PVA/PAA-HA (two-component) and PVA/PAA-HA/P(AAm-co-VIm) (three-component) were synthesized through free-radical polymerization and assembled via polymer blending in aqueous solutions followed by cyclic freeze-thaw. The polymers and polymer network assemblies were systematically characterized by FTIR, NMR and FESEM and were investigated for organic dyes adsorption. The IPN hydrogels were strong and stable adsorbents based on their mechanical rigidity and dimension. Excellent swelling percentages (>3000 %) in DI water indicated their superabsorbent properties owing to the hydrophilic polymers, leading to the pore opening within the swollen IPN adsorbents, which facilitates the cationic methylene blue (MB) adsorption onto the adsorbents. In contrast to the low removal of anionic methyl orange (MO) dye, high removal percentages (>90%) and adsorption capacities (~230 mg g-1) observed for MB dye by both PVA/PAA-HA and PVA/PAA-HA/P(AAm-co-VIm) adsorbents suggested selective chemisorption towards cationic species, which corresponded to the pseudo-second order kinetic model. The fitting of the experimental adsorption data indicates different adsorption isotherms of MB for the IPN adsorbents. Whilst the PVA/PAA-HA adsorbent obeyed the Langmuir model, the PVA/PAA-HA/P(AAm-co-VIm) adsorbent followed the Freundlich model for the MB adsorption in aqueous solutions.