Removal of wastewater phenolic compounds with triethylenetetramine functionalized polystyrene resin

A polyamine functionalized polystyrene resin (PSATA) was prepared via condensation reaction of acetylated polystyrene resin with triethylenetetramine, which, upon NaBH₄ reduction, produced PSATAR. In comparison with the PSATA, the PSATAR with more flexible amine groups shows improved structural properties, and the equilibrium adsorption capacities of phenol, 2-nitrophenol (ONP) and 2,4-dinitrophenol (DNP) in wastewater were up to 1.073, 1.832 and 1.901 mmol/g, respectively. Their adsorption isotherms fit well with the Freundlich model, indicating a multilayer, heterogeneous adsorption nature. Kinetic studies indicated that the adsorption of phenolic compounds conforms to the pseudo-second-order kinetics with the adsorption rate controlled by film diffusion for ONP and DNP, and intra-particle diffusion in the later stage for phenol.