pH-Dependent interaction of sulfamethoxazole with crosslinked poly(N-vinyl-2-pyrrolidone)

Summary The sorption of sulfamethoxazole (SM) to crosslinked poly(N-vinyl-2-pyrrolidone) (CPVP) was studied by batch adsorption technique at pH's 1.0, 5.0 and 7.0 and at temperatures 10 and 30°C. Analysis by Scatchard method and Giles adsorption isotherm indicated that (i) the sorption increased in the order of pH, 7.0<1.0<5.0 and (ii) SM sorbed vertically through a monofunctional group. The peculiar sorption at pH 5.0 was explained in terms of CPVP — H₂O interaction. The water-uptake by CPVP was minimum at pH 5.0 and increased at pH's 1.0 and 7.0.