New double network hydrogel adsorbent: Highly efficient removal of Cd(II) and Mn(II) ions in aqueous solution

Abstract

A poly(sodium acrylate)–graphene oxide (PSA–GO) double network hydrogel adsorbent was facilely prepared in mild conditions. The chemical composition of the hydrogel adsorbent was characterized by FITR, Raman spectra and XPS analysis. The uniaxial compression tests proved extraordinary mechanical strength of PSA–GO gel, benefiting to practical application. The PSA–GO hydrogel was used as an adsorbent for heavy metal ions such as Cd(II) and Mn(II). The adsorption behaviors in different conditions (e.g., pH, contact time, ionic concentration and existence of fulvic acid) as well as the adsorption mechanism were studied. The maximum sorption capacities were found up to 238.3mg/g and 165.5mg/g at pH=6 and T=303K, for Cd(II) and Mn(II), respectively, estimating from the Langmuir model. After experiencing four cycles, this adsorbent kept high removal efficiencies of Cd(II) and Mn(II), indicating a good reusability. Cost analysis reveals that the adsorbent is relatively low-cost. Meanwhile, its satisfactory performance in practical industrial effluent test demonstrates that PSA–GO gel can be a potential candidate for practical application.