Synthesis of CNT/UiO-66-NH2 adsorbent and the selective adsorption of gallium in solution

To alleviate the supply–demand contradiction of gallium metal (Ga), this study reports a method of preparing 2-CNT/UiO-66-NH2 composite materials by combining carbon nanotubes (CNTs) with UiO-66 series metal–organic frameworks (MOFs) to improve the recovery and utilization efficiency of Ga in solution. The adsorbent material is used for selective adsorption and recovery of Ga in aqueous solutions. The physical properties of the composite adsorbent, such as morphology, structure, and elemental composition, were explored by analyzing the surface characteristics of the samples. The impacts of variables like the amount of adsorbent used, time, solution concentration, pH value, and coexisting ions on adsorption efficiency were explored during the experiment. The results indicate that ion exchange and chelation play a major role in the adsorption of Ga by 2-CNT/UiO-66-NH2, and Ga ions can be separated and recovered from the mixed solution through selective adsorption. At 313 K and pH = 8, the greatest amount of adsorption is 925.44 mg/g, and the rate at which it is absorbed can reach 99% when the adsorption time is only 1 h. The hybrid absorbent generally has a high adsorption efficiency and good selective adsorption performance for Ga, providing more efficient and economical technical assistance for the future recovery and exploitation of Ga supplies.