Magnetic porous polymer composite for high performance adsorption of acid red 18 based on melamine resin and chitosan

摘要

Magnetic porous Fe3O4/MRCS polymer composite was prepared by reacting melamine-formaldehyde resin with chitosan in the present of amino modified Fe3O4 nanoparticles and used as adsorbent for acid red 18 azo dye removal. The Fe3O4/MRCS was characterized by TEM, SEM, XRD, TGA and BET analysis. The Fe3O4/MRCS possessed high BET surface area (226.6 m(2)/g), characteristic pore properties and facile magnetic separation function. The average pore width is 6.5 nm and the pore volume was 0.68 cm(3)/g. The Fe3O4/MRCS presented enhanced high adsorption performance toward acid red 18. It removed 99. 65% of acid red 18 (100 mg/L) when the adsorbent amount was over 0.8 g/L. It was found the absorption was depended on pH and the removal efficiency decreased with pH increased. The maximum adsorption capacity of acid red 18 reached as high as 301.0 mg/g. The adsorption kinetic followed the pseudo-second-order kinetics model and the activation energy of the adsorption process was 38.40 kJ/mol. The adsorption isotherms were best fitted to the Redlich-Peterson isotherm equation. Thermodynamic studies indicated the adsorption process was spontaneous and endothermic in nature. The adsorption mechanism study showed the adsorption was a heterogeneous chemisorption process with multiple interactions, involving pore filling, electrostatic attraction, affinity interaction, intra-particle diffusion, pi-pi interaction and polymer chain inclusion and polymer net trapping. In comparison with other reported adsorbents, the magnetic porous Fe3O4/MRCS showed superior adsorption performance for acid red 18 removal. (C) 2019 Elsevier B.V. All rights reserved.