Adsorption of Sulfur Dioxide on Poly(vinylpyridine) Resins with Porous Structure

Abstract

Various macroreticular type resins were prepared by suspension copolymerization of many Vinyl pyridine derivatives with divinyl benzene in the presence of iso-octane as diluent. The adsorption capacities of these resins were greatly varied with the nature of vinyl pyridine ut monomer species and the ability decreased in the following order: poly(4-vinylpyridine)>poly-(2-methyl-5-vinylpyridine)>poly(2-vinylpyridine)upoly(5-ethyl-2-vinylpyridine). However, the variation in the pore structure of resin had little effect on adsorption capacity. The adsorption on porous resins was generally represented by BET type adsorption isotherm and the heats of adsorption were calculated as lo to 14.5 kcal/mol by use of Clausius-Clapeyron equa tion, larger than one of styrene-divinyl benzene copolymer, Amberlite XAD-2. The adsorption characteristic on the gel type resin was expressed as Henry s type adsorption isotherm. This fact indicates that sulfur dioxide is absorbed into the resin matrix and subsequently reacts with functional groups. lnfrared spectrum of poly(4-vinylpyridine) film exposed to sulfur dioxide gas had characteristic bands caused by SO₂-pyridine molecular complex formation at 1280, 1125, 534 cm^-1 and also indicated a band for SO₃^2- group (S-O stretching) at 940 cm.