Adsorption of Aromatic Compounds from Aqueous Solution by a Hypercrosslinked Polymeric Adsorbent with Sulphonic Groups

Abstract

A hypercrosslinked polymeric adsorbent with sulphonic groups, NG-5, was employed to remove p -toluidine, p -aminophenol and phenol from aqueous solutions and its performance and thermodynamic behaviour compared to that of the hypercrosslinked polymeric adsorbent CHA-111 containing no functional groups. It was found that the equilibrium adsorption data for the three aromatic compounds could be well fitted by the Langmuir and Freundlich isotherms. The results showed that the equilibrium adsorption capacities for p -toluidine and p -aminophenol on NG-5 were all greater than on CHA-111. This may be attributed to the strong hydrogen-bonding interaction between the adsorbent and the adsorbate, electrostatic interaction and π–π interaction. However, the adsorption capacity for phenol on NG-5 was lower than that on CHA-111 because of the larger surface area and micropore volume of the latter adsorbent. The sorption enthalpy changes were used to interpret the adsorption mechanism. In addition, the sorption of p -toluidine and p -aminophenol onto NG-5 was studied kinetically. The results showed that the adsorption process was mainly controlled by intraparticle diffusion.