Adsorption removal of pharmaceutical and personal care products with functionalized metal-organic framework: adsorptive selectivity and mechanism

Pharmaceutical and personal care products (PPCPs) had been detected worldwide as an emerging contaminant in the aquatic system. Herein, we reported a kind of NH2-functionalized UiO-66 which exhibited effective removal toward diflunisal and salicylic acid. The capacity of UiO-66-NH2 was much higher than commercial activated carbon (AC) for the adsorption of PPCPs and it was because UiO-66-NH2 had a smaller pore size than AC. The UiO-66-NH2 also indicated some interactions, like pi-pi stacking and electrostatic interaction. The removal efficiency of diflunisal and salicylic acid from wastewater with the UiO-66-NH2 groups was higher than the original UiO-66. It could be explained with the acid-base attraction between the NH2 group of UiO-66-NH2 and the COOH group of diflunisal and salicylic acid. However, the performance of UiO-66-NH2 in the adsorption of carbamazepine was not very desirable. The base-base repulsion between the NH2 group of UiO-66-NH2 and the NH2 group of carbamazepine led to a decrease in the adsorption capacity of UiO-66-NH2. The UiO-66-NH2 could be regenerated with ethanol and reused for the adsorption removal of the adsorbates.