Further studies on the adsorption of plant phenols by synthetic polymers

Abstract

Pyrocatechol, catechol, caffeic acid, chlorogenic acid, safflor yellow A, safflor yellow B, precarthamin and carthamin were effectively adsorbed by insoluble polyvinyl-N-pyr­rolidone (PVP) in a neutral buffer solution. These eight phenols also bound with Amberlite XAD resins, however, the rate was found to be far less efficient than that of PVP. The average rate of the phenol binding was calculated as following order (%): PVP (42.7), Amberlite XAD-2 (16.6), Amberlite XAD-4 (10.1), Amberlite XAD-7 (13.0), Amberlite XAD-8 (17.7). No 3,4-dihydroxyphenylalanine was adsorbed by PVP, while the O-dihydroxylic acid could be removed by Amberlite XAD-4, XAD-7 and XAD-8. Data from using different weights of the test polymers showed that the rate of the phenol adsorption rose in proportion to each increasing amount of the adsorbents. PVP also admittedly maintained its predominent capacity for phenol binding over that of each member of the Amberlite resins.

Keywords

• plant phenols
• polyvinyl-N-pyrrolidone
• Amberlite XAD resin
• adsorption