Adsorption of 5-sodiosulfoisophthalic acids from aqueous solution onto poly(2-vinylpyridine) resin.

In the present study, the performance, behavior and mechanism of synthetic poly(2-vinylpyridine) resin (WH-225) adsorbing 5-sodiosulfoisophthalic acids (SIPA) from the aqueous solution were investigated, and two commercial adsorbents, namely, hypercrosslinked adsorbent NDA-100 and macroporous adsorbent XAD-4 were employed as reference. Compared to NDA-100 and XAD-4, WH-225 has the highest capacity for adsorbing SIPA from the aqueous solution, which is verified by the related adsorption experiments. The investigation indicated that electrostatic interaction is an important factor in affecting the adsorption behavior of WH-225. The Freundlich isotherm equation was successfully applied to describe the adsorption isotherms. The negative values of the adsorptive enthalpy changes indicate an exothermic process for WH-225, and the absolute values (<43 kJ mol(-1)) further manifest a physical adsorption process. The column adsorption and desorption tests further proved WH-225 is a promising adsorbent for field applications to remove and recover aromatic acids (e.g. SIPA) from aqueous solution.