Adsorption of phosphate on UiO-66-NH2 prepared by a green synthesis method

In this study, a zirconium-based metal organic framework (UiO-66-NH2) was prepared with a green synthetic method for removal of phosphate from solution. Several characterization methods were performed and the adsorption property of UiO-66-NH2 toward phosphate was explored in batch mode. There was a good adsorption performance for phosphate with a wide range of pH (pH = 2–11) with a slight effect of salinity. The adsorption capacity was up to 43.9 mg·g–1 at 303 K from experiments. The adsorption isotherms can be better described by Langmuir, Temkin, and Koble-Corrigan model while adsorption kinetics can be well fitted by Pseudo-second-order, Double Constant and Elovich model. The process was spontaneous and exothermic and the major mechanism of phosphate adsorption was complexation. The spent adsorbent can be well regenerated using 0.01 mol·L–1 NaOH. The study shows that UiO-66-NH2 has the potential to remove phosphate from solution.