Rubidium ion Capture with a phosphotungstic acid-functionalized finger-citron-residue-based carbon

To solve the contradiction of diffusion and selectivity, we reported a novel finger-citron-residue-based mesoporous carbon (FMC) as a support to prepare a novel adsorbent PTA@FMC (PTA represents phosphotungstic acid) for rubidium ion capture. This new adsorbent was characterized by X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and N(2) adsorption, and the results showed that the PTA was immobilized in the FMC structure. Based on the results of batch tests, we demonstrated that PTA@FMC is the most distinctive adsorbent with a superior uptake capacity compared with some of those previously reported in the literatures. The adsorption tests in the presence of interfering ions (Na(+), K(+) and Cs(+)) showed that the more the added amount of the different types of interfering ions, the more severe is the degree by which the adsorption of Rb(+) is weakened. In addition, the Rb(+) sorption selectivity was moderately influenced by the co-ion effect in the presence of any ions (K(+), Na(+) and Cs(+)) due to PTA doping. In a word, due to its relatively facile preparation process and good uptake capacity, PTA@FMC might be a promising adsorption material for Rb(+).