The specific recognition and binding ability of Cr(VI)-IIP and NIP for Cr(VI) were investigated in binary mixed solutions of Cr(VI)/Cr(III), Cr(VI)/Cu(II), Cr(VI)/Cd(II) and Cr(VI)/Ni(II), respectively. These four metal ions were selected as competing ions for Cr(VI) based on the principle of the same element or the same charge. The experimental results were given in Table 2. The K_d value of Cr(VI) (K_d = 4,351 mL/g) was much larger than that of Cr(III) (K_d = 290 mL/g), illustrating that the prepared Cr(VI)-IIP could realize the separation of different valence states of Cr element. Meanwhile, the K_d of NIP for competing ions was close, leading to the k_NIP around 1. In contrast, the k_IIP for competing ions was far greater than 1. These data proved that Cr(VI)-IIP had a strong selective adsorption ability for Cr(VI) under the interference of other metal ions. Moreover, according to the values of k′, Cr(VI)-IIP had a higher selective adsorption capacity for Cr(VI) than NIP. These were because during the imprinted process, functional monomers 4-VP and MAA were coordinated to Cr(VI) to form abundant Cr(VI) imprinted sites, which had a strong specific recognition ability for Cr(VI) (Fei et al. 2021). However, functional monomers in NIP were polymerized randomly, resulting in a random arrangement of functional groups on the polymer surface (Guo et al. 2013). These functional groups do not have specific recognition ability for Cr(VI), so the NIP had no selective adsorption ability for Cr(VI).