Influence of the porous structure and functionality of the MIL type metal-organic frameworks and carbon matrices on the adsorption of 2,4-dichlorophenoxyacetic acid

The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solutions on different porous materials was studied. The materials included micro- and mesoporous carbon matrices of different genesis and metal-organic frameworks (MOFs) of the MIL type such as microporous matrices MIL-53(Al) (AlOHbdc, bdc = benzene-1,4-dicarboxylate) and NH2-MIL-53(Al) (AlOHbdc, abdc = 2-aminobenzene-1,4-dicarboxylate), as well as mesoporous matrix NH2-MIL-101(Al) (Al3O(abdc)3). It is found that the efficiency of liquid phase adsorption is affected by the texture and functionality of the studied materials, whereas in the case of MOFs, the adsorption efficiency is also under the influence the framework flexibility. The MOF materials and mesoporous carbon matrices show a higher adsorption rate than microporous carbon matrices. The flexible microporous MIL-53(Al) framework and microporous coconut shell activated carbon (CSAC) exhibit the highest adsorption capacity with respect to 2,4-D.