Synthesis of novel MOF for adsorption of germanium: Kinetics, isotherm and thermodynamics

As a semiconductor material, effective recycle and utilization of germanium is an important research direction. In this paper, an efficient adsorbent for recovery of germanium is prepared by grafting D-anhydrous glucose onto UiO-66-NH2 (DG-UiO-66). The successful preparation of adsorbent is demonstrated through a series of characterizations. Under the optimum experimental conditions (298 K, pH = 10), the maximum adsorption capacity of germanium by DG-UiO-66 is 216.86 mg/g. The adsorption behavior of Ge(IV) on the adsorbent is analyzed, and the adsorption of Ge(IV) conform to the pseudo-secondary kinetic model and Langmuir isotherm model, and the adsorption mechanism of germanium is further analyzed by intraparticle diffusion model. The thermodynamic results show that the higher the temperature, the stronger the adsorption capacity of Ge(IV), and the reaction is spontaneous. The adsorbent has good anionic anti-interference ability, and the adsorption efficiency can still reach more than 80% after repeated adsorption for five times. DG-UiO-66 is an excellent Ge(IV) ion adsorbent with higher germanium adsorption effect than previous adsorbents.