Polymer Bulletin 44, 501–508 (2000) * Corresponding author Polymer Bulletin Springer-Verlag 2000 Binding of some dyes onto crosslinked poly (N-vinylpyrrolidone) Dursun Saraydin 1,* , Erdener Karadag 2 1 Chemistry Department, Cumhuriyet University, 58140 Sivas, Turkey 2 Chemistry Department, Adnan Menderes University, 09010 Aydin, Turkey Received: 10 April 2000/Revised version: 26 May 2000/Accepted: 6 June 2000 Summary Bindings of some anionic dyes containing sulfonyl group(s), namely, Acid Blue 74 (AB-74), Acid Orange 7 (AO-7), Acid Green 1 (AG-1), Direct Blue 53 (DB-53), and Calconcarboxylic acid (CCA) onto crosslinked poly(N-vinylpyrrolidone) (CPVP) have been investigated using adsorption isotherm parameter. The dyes were linked positively charged on the tertiary nitrogen atom on the pyrrolidone ring in polymer chain resulting keto-enol tautomerism from sulfonyl group on the benzene ring in the dyes molecules. In the experiments of adsorption, L (Langmuir) type adsorption in the Giles classification system was found. Monolayer coverages (n) of polymer/dye system were founds by "B point" methods. Adsorption studies indicated that monolayer coverages of CPVP by the anionic dyes containing sulfonyl group(s) were increased with following order; CCA > AG-1 >> DB-53 > AO-7 > AB-74. Key words: crosslinked poly(N-vinylpyrrolidone), anionic dye, binding, adsorption. Introduction Poly(N-vinylpyrrolidone) (PVP) is a polymeric compound that is widely used for textiles, cosmetics and toiletries, pharmaceuticals, etc. It has the property of forming complexes with a variety of substances. The interaction of PVP have been discussed with certain inorganic and organic compounds. The interactions between PVP and anionic dyes have been studied only to a limited extend, and sufficient information is not available on the effect of polymer chain or the composition of the anionic dyes containing sulfonyl group in the interaction. Crosslinked poly(N- vinyl pyrrolidone) (CPVP) has similar behaviour as PVP. CPVP is also the adsorbent for the chromatographic separation of aromatic acids, aldehydes, and phenols (1-5). * To whom correspondence addresses. e-mail: saraydin@cumhuriyet.edu.tr (D. SARAYDIN)