Imparting UiO-66 with fast cation exchange property via sulfonating organic linkers for selective adsorption.

UiO-66(Zr) is functionalized with sulfonic acid groups to deliver high cation exchange property, due to the electrostatic force contributed from the introduced SO 3 − groups to attract ions of opposite charge. • UiO-66(Zr) can be imparted with fast cation exchange kinetics via the sulfonation of organic linkers. • The role of sulfonation of a MOF in adsorption separation of ionic dyes is reported. • The sulfonated UiO-66 can effectively absorb cationic dyes and reject anionic dyes due to electrostatic attraction between SO 3 - groups and dye cations. • The synthesis is simple and scalable, this opens new avenues for the industrial applications of MOFs in aqueous system. Adsorption is the simplest in operation and most cost-effective approach to remove pollutants in an aqueous environment. Advanced adsorbents providing selective ion adsorption of target dyes in an aqueous environment are desirable to ensure good water quality before discharged as wastewater. Metal organic frameworks (MOFs), despite high surface area and high porosity, generally exhibit poor ion-selectivity, thus, hindering their applications in dye removal from industrial wastewater. We report, for the first time, the high cation exchange performance of UiO-66 functionalized via sulfonation of its organic linkers (UiO-66-SO 3 H). More than 90% of cationic methylene blue dye solution was adsorbed by the UiO-66-SO 3 H while rejecting 100% anionic acid blue dye. The cation adsorption selectivity of UiO-66-SO 3 H is superior to the performance of the commercially available cation exchange Amberlite IR-120 resin. The synthesis of the sulfonated UiO-66 is simple and scalable. This material is promising for the industrial-based applications in aqueous-based separations of ions, and dye removal from wastewater. [ABSTRACT FROM AUTHOR]