Selective Adsorption Behavior of Gallium Ions on Graphene‐Based Surface Ion‐Imprinted Material From Simulated Acid Leach Solution of Fly Ash

A graphene-based material for the selective adsorption of gallium ions has been prepared by combining ion-imprinting technology with adsorption. This material is capable of separating and extracting gallium ions from the acid leachate of fly ash. Morphological and structural characterization of the material was performed using scanning electron microscopy and Fourier-transform infrared spectroscopy, which confirmed that the material possesses a three-dimensional structure and that functional monomers have successfully complexed with graphene oxide substrates. The maximum adsorption capacity of the material reaches 86.29 mg/g at a solution pH of 3. In the selective adsorption tests, the selective separation factors of gallium ions relative to aluminum, magnesium, iron, and calcium ions were 16.50, 49.50, 9.90, and 99.00, respectively. Meanwhile, the material maintained excellent adsorption capacity and structural stability in cyclic regeneration experiments, with no obvious dissolution loss observed. The adsorption mechanism of the material was analyzed via X-ray photoelectron spectroscopy, and the results indicated that it primarily involves cation exchange between carboxyl groups and gallium ions. This work demonstrates that the three-dimensional ion-imprinted hydrogel adsorbent plays a significant role in the selective adsorption of gallium ions and the subsequent solid-liquid separation.