Abstract: A novel integrated film of sulfonated polysulfone/graphene/potassium copper ferricyanide (KCuFC/SPSG) was used for selectively extracting rubidium ion (Rb⁺) from brine. To form KCuFC/SPSG, the precursor film of sulfonated polysulfone/graphene (SPSG) was synthesized by phase conversion process, which was alternately immersed in 0.1 mol·L^-1 CuSO₄/K₄[Fe(CN)₆] by in-situ adsorption coupled co-precipitation method. Various data such as nuclear magnetic resonance spectrometer, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy all verified that abundant KCuFC were uniformly located on the film. The resulting KCuFC/SPSG was used in film separation system. As the solution was fed into the system, the Rb⁺ could be selectively adsorption by KCuFC/SPSG. After the saturation adsorption, 0.5 mol·L^-1 NH₄Cl/HCl was fed into the film cell, Rb⁺ could be quickly desorbed by ion-exchange between Rb⁺ and NH₄⁺ in the lattice of KCuFC. The purpose of separating and recovering Rb⁺ from the brine can be achieved after the repeated operation. The effects of pH, adsorption time, and interferential ions on the adsorption capacity of Rb⁺ were investigated by batch experiments. The adsorption behavior fits the pseudo-second order kinetic process, while KCuFC has a higher adsorption capacity (Langmuir maximum sorption 165.4 mg·g^-1). In addition, KCuFC/SPSG shows excellent selectivity for Rb⁺ even in complex brine systems. KCuFC/SPSG could maintain 93.5% extraction efficiency after five adsorption/desorption cycles.

Key words: Rubidium extraction, Potassium copper ferricyanide, Sulfonated polysulfone, Graphene oxide, Adsorption

摘要： A novel integrated film of sulfonated polysulfone/graphene/potassium copper ferricyanide (KCuFC/SPSG) was used for selectively extracting rubidium ion (Rb⁺) from brine. To form KCuFC/SPSG, the precursor film of sulfonated polysulfone/graphene (SPSG) was synthesized by phase conversion process, which was alternately immersed in 0.1 mol·L^-1 CuSO₄/K₄[Fe(CN)₆] by in-situ adsorption coupled co-precipitation method. Various data such as nuclear magnetic resonance spectrometer, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy all verified that abundant KCuFC were uniformly located on the film. The resulting KCuFC/SPSG was used in film separation system. As the solution was fed into the system, the Rb⁺ could be selectively adsorption by KCuFC/SPSG. After the saturation adsorption, 0.5 mol·L^-1 NH₄Cl/HCl was fed into the film cell, Rb⁺ could be quickly desorbed by ion-exchange between Rb⁺ and NH₄⁺ in the lattice of KCuFC. The purpose of separating and recovering Rb⁺ from the brine can be achieved after the repeated operation. The effects of pH, adsorption time, and interferential ions on the adsorption capacity of Rb⁺ were investigated by batch experiments. The adsorption behavior fits the pseudo-second order kinetic process, while KCuFC has a higher adsorption capacity (Langmuir maximum sorption 165.4 mg·g^-1). In addition, KCuFC/SPSG shows excellent selectivity for Rb⁺ even in complex brine systems. KCuFC/SPSG could maintain 93.5% extraction efficiency after five adsorption/desorption cycles.

关键词: Rubidium extraction, Potassium copper ferricyanide, Sulfonated polysulfone, Graphene oxide, Adsorption