Base-functionalized metal−organic frameworks for highly efficient removal of organic acid pollutants from water

Abstract

Organic acid contaminated wastewater has been of great concerns for water recovery. Base-functionalized metal−organic framework DETA-UiO-66 by grafting diethylenetriamine onto UiO-66 achieved remarkable H2-FA capacity with large adsorption rate compared with parent UiO-66 and sulfonate-functionalized SO3H-UiO-66. According to the adsorption behavior at various pHs, an adsorption mechanism was proposed involving the acid–base interaction and weak electrostatic interaction. Further investigation including adsorption kinetics, isotherms, thermodynamics, demonstrated that the H2-FA adsorption process on DETA-UiO-66 was a spontaneous exothermic process with a theoretical adsorption capacity reaching up to 561.8 mg g−1 at 10 °C. In addition, DETA-UiO-66 can be recovered through simple ethanol washing and reused for at least three times, remaining high adsorption capacity and adsorption rate. Meanwhile, DETA-UiO-66 showed high adsorption capacities for citric acid and sorbic acid, indicating DETA-UiO-66's wide potentials in capturing various organic acid pollutants.