Adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from water with a metal-organic framework

Adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) using a MOF (metal-organic framework), Cr-benzenedicarboxylate (MIL-53), has been studied for the first time to understand the applicability of MOFs in the removal of hazardous herbicides from contaminated water. MIL-53 has a very fast adsorption in one hour and the adsorption capacity of MIL-53 is much higher than that of activated carbon or zeolite (USY). Importantly, the adsorption of 2,4-D over MIL-53 is very favorable especially at low concentrations of 2,4-D. Moreover, the adsorbent can be used several times in adsorptive removal by washing the used adsorbent with a simple solvent. Therefore, MOFs such as MIL-53 can be one of adsorbents that could be used in the adsorptive removal of 2,4-D from contaminated water. Additionally, zeta potential of the adsorbent and the effect of pH and temperature on the adsorption were also investigated, and a plausible adsorption mechanism could be suggested. (C) 2013 Elsevier B.V. All rights reserved.