Defective UiO-67 for enhanced adsorption of dimethyl phthalate and phthalic acid

It is imperative to remove endocrine disrupting compounds (EDCs) from water because of their damage to human health via drinking, eating and skin contacting. Herein, a variety of UiO-67 samples, with different numbers of defects were screened for the adsorption elimination of dimethyl phthalate (DMP) and phthalic acid (PA) in aqueous solution. UiO-67-30BA (benzoic acid regulator with 30 times molar number of ligands) which had the greatest number of missing-links and the highest specific surface area, was determined by thermogravimetric analysis (TGA), nuclear magnetic resonance (1H‐NMR), and energy-dispersive X-ray spectroscopy (EDS) and N2 adsorption-desorption. The adsorption kinetics of PA and DMP on UiO-67-30BA well obeyed pseudo-first-order kinetic model and the adsorption isotherms well followed Langmuir model. Adsorption thermodynamics indicated that the adsorption process was an exothermic and spontaneous process. Remarkably, UiO-67-30BA with the most defects showed the third highest PA and highest DMP adsorption capacity compared with reported MOFs materials, which were 434.0 and 228.1 mg/g, respectively. Furthermore, the dominant interactions between PA and UiO-67 samples were electrostatic interaction and π-π interaction, while the adsorption of DMP depended on π-π interaction. The introduction of missing-links not only provided an outstanding adsorbent UiO-67-30BA for DMP and PA, but also revealed the different adsorption mechanisms of the adsorbents.