Amidation modified waste polystyrene foam as an efficient recyclable adsorbent for organic dyes removal

Modifying the environmentally harmful waste polystyrene foam as an efficient recyclable adsorbent for organic dyes is important. Amidation modified polystyrene (PS-SD) was prepared by the Friedel-Crafts reaction and N,N'-dicyclohexylcarbodiimide (DCC) dehydration condensation reaction of waste polystyrene foam. PS-SD had highly efficient removing performance for organic dyes in large volume of water sample solutions, and the equilibrium was achieved in 0.5 h. The maximum adsorption capacity for Methylene blue (MB) and Congo red (CR) were 881.62 and 1,880.91 mg/g, respectively, at room temperature according to the Langmuir adsorption isotherm (R-2 > 0.99). The kinetic data of the two dyes followed the pseudo-second-order kinetics. The removal percentage remained high (>85%) after eight filtration-regeneration cycles. Experimental results showed that PS-SD was an excellent adsorbent for water treatment with high recyclability and long life.