Highly effective adsorption of copper ions by poly(vinyl imidazole) cryogels.

Recently, 3D cryogels with the interconnected macropore structure have gained great attention owing to their immense application potential in wastewater cleanup. Here, we fabricated a pure poly(vinyl imidazole) cryogel through improved cryogelation method, adding the pre-freezing–thawing step, which reduced the temperature difference between the different positions of the precursor solution during reaction. Compression experiments showed that the prepared 3D cryogel featured a robust underwater elastic performance. The adsorption capacity of Cu(II), Ni(II), Zn(II), Co(II), Pb(II), and Cd(II) ions from aqueous solutions by the poly(vinyl imidazole) cryogel was explored. The results showed the specific adsorption of Cu(II), in which the adsorption capacity and removal efficiency reached 148 mg/g and 99.99%, respectively. The adsorption capacity was 58 times higher than that of the reported poly(vinyl imidazole) cryogel which was prepared using hydroxyethyl methacrylate as the comonomer frameworks. In the reusability studies, the cryogel exhibited accumulating Cu(II) ions performance and excellent regeneration capability, making it a promising adsorbent for Cu(II) removal. [ABSTRACT FROM AUTHOR]