Removal of Cr(VI) from solution using UiO-66-NH2 prepared in a green way

A zirconium-based metal organic framework (UiO-66-NH2) was prepared using a greener approach for the removal of hexavalent chromium (Cr(VI)) from solution. The characterization of UiO-66-NH2 was performed using several methods, and the influence of the solution pH, adsorbent dosage, salt, adsorption time, Cr(VI) concentration and adsorption temperature on adsorption quantity was performed in batch mode. UiO-66-NH2 can efficiently remove Cr(VI) through the synergistic effect of adsorption and reduction. At pH solution of 1.1 and solid-to-liquid ratio of 2 g·L−1, the removal rate of 100 mg·L−1 Cr(VI) increased to 95.2%. The maximum adsorption capacity of UiO-66-NH2 from Langmuir model was 252 mg·g−1. The adsorption equilibrium process can be well described by Langmuir, Koble-Corrigan and Temkin models, while the kinetic process can be predicted by pseudo-second-order and Elovich model. UiO-66-NH2 showed a good adsorption capacity in a wide range of pH (pH=1.1–10) and also had better regeneration performance after five cycles using 0.01 mol·L−1 NaOH; consequently, it can be a promising adsorbent for the removal of Cr(VI) from solution.