Functional group-rich hyperbranched magnetic material for simultaneous efficient removal of heavy metal ions from...

In order to achieve the purpose of simultaneous removal of coexisting heavy metal ions, in this work, functionalized magnetic mesoprous nanomaterials (Fe₃O₄-HBPA-ASA) with high density and multiple adsorption sites were designed and prepared. The obtained Fe₃O₄-HBPA-ASA was characterized by SEM, FTIR, VSM, TGA and zeta potential. Cu(II), Pb(II) and Cd(II) were chosen as the model heavy metal ions, the adsorption experiments showed that Fe₃O₄-HBPA-ASA showed hightheoretical adsorption capacitiesin individual system, and the maximum adsorption capacity was 136.66 mg/g, 88.36 mg/g and 165.46 mg/g, respectively. In the binary and ternary systems, the competitive adsorption leads to a decrease in the adsorption capacity of Cu(II), Pb(II) and Cd(II). However, in the ternary system with a concentration lower than 15 mg/L, the simultaneous removal rate was still higher than 90%. The adsorption isotherms and kineticswere well fitted by Langmuir and pseudo-second-order models, respectively. The XPS and density functional theory (DFT) analysis have confirmed that the adsorption of metal ions was related to various types of functional groups on the surface of Fe₃O₄-HBPA-ASA, while the adsorption mechanisms of Cu(II), Cd(II) and Pb(II) were different.