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

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-SO3H). More than 90% of cationic methylene blue dye solution was adsorbed by the UiO-66-SO3H while rejecting 100% anionic acid blue dye. The cation adsorption selectivity of UiO-66-SO3H 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.