Adsorptive removal of artificial sweeteners from water using porous carbons derived from metal azolate framework-6

Elimination of artificial sweeteners (ASWs) from water is receiving much attention these days because of their detrimental effects. In this study, metal organic framework (here, metal azolate framework-6 (MAF-6))-derived porous carbons (MDCs) prepared for different pyrolysis times were used to remove ASWs such as saccharin, acesulfame, and cyclamate from water. The MDC prepared for 6 h (MDC-6h) showed a remarkably high adsorption capacity compared to that of commercial activated carbon (AC) and other adsorbents. For example, MDC-6h adsorbed 93 mg/g of saccharin from water after 12 h of adsorption whereas AC adsorbed only 4.7 mg/g under the same condition. Moreover, H-bonding between the surface functional groups of MDC and ASWs was suggested as the main mechanism of ASW adsorption, where MDC-6h (especially the phenolic group) and the ASW act as the H-donor and H-acceptor, respectively. Additionally, MDC-6h can be easily regenerated by simply washing with acetone. Therefore, MDC-6h Is recommended as an outstanding adsorbent for ASW removal from water.