Effects of multiple weak interactions on the binding of phenolic compounds by polymeric adsorbents

To investigate the effects of multiple weak interactions on the binding of phenolic compounds by polymeric adsorbents, macroporous polystyrene (PS) resin and PS-based adsorbents with different hydrogen-bond acceptor atoms (PS-CH2(-OCH2CH2) -OCH3, n = 0, 1, 2, and 3, denoted as PS-EG(0), PS-EG(1), PS-EG(2), and PS-EG(3)) were prepared. The phenol adsorption strength order on these adsorbents was PS/PS-EG(0) < PS-EG(1) < PS-EG2 < PS-EG3, indicating that the adsorption on PS and PS-EGO was driven by hydrophobic and pi-pi interactions, and the adsorption on PS-EG(1), PS-EG(2), and PS-EG(3) was driven by a hydrogen bond in addition to hydrophobic and pi-pi interactions. PS-EG(2) may adsorb a second phenol molecule on each binding site and PS-EG(3) may adsorb second and third ones. The adsorption strength of resorcinol increased in the order of PS, PS-EG(1), and PS-EG(2), indicating that the adsorption was driven by 0, 1, and 2 hydrogen bonds in addition to hydrophobic and pi-pi interactions. Similarly, the adsorption of phloroglucinol on PS, PS-EG(1), PS-EG(2), and PS-EG(3) was driven by 0, 1, 2, and 3 hydrogen bonds in addition to hydrophobic and pi-pi interactions because the adsorption strength increased in this order. (c) 2006 Wiley Periodicals, Inc.