Application of hydrogel for the removal of pollutant phenol in water

We prepared hybrid hydrogel of N-isopropyl acrylamide (NIPAM) and tributyl phosphate (TBP) for removing phenol by adsorption. The hybrid hydrogel was reinforced by thin layer coating of calcium alginate gel which was cross-linked by bivalent calcium ions. The prepared hybrid hydrogel was shown to effectively adsorb phenol from aqueous solution. The adsorption kinetic measurement showed that the thin layer coating of calcium alginate gel hardly hindered the mass transfer process of phenol. This is because of the superior hydrophilicity of calcium alginate gel which allows phenol molecules to diffuse in the hybrid hydrogel. The reinforced hybrid gel could be stripped of the adsorbed phenol with ammonia aqueous solution for multiple times. The thin layer coating of calcium alginate provided the hybrid hydrogel sufficient durability to carry out repeated cycles of adsorption and desorption.