Preparation of highly-hydrophobic novel N-coordinated UiO-66(Zr) with dopamine via fast mechano-chemical method for (CHO-/Cl-)-VOCs competitive adsorption in humid environment

A novel mechano-chemical strategy using dopamine to modify UiO-66(Zr) by N-coordination was proposed to enhance its competitive adsorption for acetaldehyde, chlorobenzene/H2O, both thermodynamically and kinetically. The newly synthesized material was characterized by SEM, EDX, XPS, PXRD, FT-IR, TGA/DTG and BET techniques. Results showed that N was successfully grafted into UiO-66(Zr) frameworks through coordination interaction with Zr-O clusters resulting in M-UiO-66(Zr-N-3.0). The obtained M-UiO-66(Zr-N-3.0) exhibited a significant increase in adsorption of chlorobenzene (4.94 mmol/g) and acetaldehyde (9.42 mmol/g) compared to parent UiO-66(Zr) and UiO-66(Zr)-NH2. The H2O adsorption uptake of M-UiO-66(Zr-N-3.0) decreased by 20% that of UiO-66(Zr) and 47% of UiO-66(Zr)-NH2 indicating higher hydrophobicity of the modified material. Kinetic performance indicated that diffusivity of chlorobenzene on M-UiO-66(Zr-N-3.0) was about 7.8 and 40 times higher than that of the parent UiO-66(Zr) and UiO-66(Zr)-NH2 respectively and 15.4 times higher than that of H2O on itself. Based on the results, the current N-modification strategy can be deemed as an efficient way to improve MOFs competitive adsorption towards VOCs under humid conditions and it might play active role in industries involving adsorbent applications.