Adsorption of Ni2+ and Cu2+ from Aqueous Solution by Polyethylenimine Impregnation of Metal–Organic Frameworks

A series of UiO-66-PEI materials were obtained by impregnating UiO-66 with different amounts of polyethylenimine (PEI) with UiO-66 as the basic skeleton material. The materials were used as adsorbents to remove Ni 2 + ${}^{2+}$ and Cu 2 + ${}^{2+}$ from water. The prepared UiO-66-PEI-30 had good adsorption capacity on Ni 2 + ${}^{2+}$ and Cu 2 + ${}^{2+}$ at 30% PEI. The adsorption of Ni 2 + ${}^{2+}$ and Cu 2 + ${}^{2+}$ with UiO-66-PEI-30 was further studied. The role of eluent types, elution time, concentration and volume on the effect of Cu 2 + ${}^{2+}$ elution was investigated. The adsorption of Ni 2 + ${}^{2+}$ and Cu 2 + ${}^{2+}$ by UiO-66-PEI-30 followed the pseudo-second-order kinetic model and Langmuir adsorption model. The maximum adsorption capacities obtained by Langmuir fitting for Ni 2 + ${}^{2+}$ and Cu 2 + ${}^{2+}$ were 11.54 $$ mg $$ g − 1 ${}^{-1}$ and 24.87 $$ mg $$ g − 1 ${}^{-1}$ , respectively. After four desorption/adsorption experiments, UiO-66-PEI-30 still showed good adsorption performance. UiO-66 impregnated with PEI was an adsorbent with adsorption potential.