Selective adsorption of Copper (Ⅱ) ions in mixed solution by Fe_3O_4-MnO_2- EDTA magnetic nanoparticles

摘要

To combine the properties of Cu2+ selective adsorption and magnetic separation of adsorbents from mixture, Fe3O4-MnO2 was modified with TMS-EDTA (N-(trimethoxysilylpropyl) ethylenediamine triacetic acid) to obtain Fe3O4-MnO2-EDTA. The as-synthesized materials were characterized and selective adsorption properties of Cu2+ were investigated under different conditions. Experimental results showed that Fe3O4-MnO2-EDTA exhibited high Cu2+ selective adsorption performance in both binary and ternary metal species systems. The selective adsorption mechanism was illuminated through the analysis of FTIR, XPS and Cu2+/Cd2+ binary kinetics experiments, in which a complexation replacement procedure could be found. Moreover, the Cu2+-adsorbed TMS-EDTA segments would generate steric hindrance to restrain Cd2+ from approaching Fe3O4-MnO2-EDTA particles. Cd2+, initially adsorbed by Fe3O4-MnO2-EDTA, finally would be replaced by other free Cu2+ and released back to the solution. CoImpared with Fe3O4-MnO2, the Fe3O4-MnO2-EDTA magnetic nanoparticles successfully combined the advantages of fast magnetic separation with high Cu2+ selectivity.