Core-shell Fe3O4@zeolite NaA as an Adsorbent for Cu2+

Here, using Fe₃O₄@SiO₂ as a precursor, a novel core-shell structure magnetic Cu²⁺ adsorbent (Fe₃O₄@zeolite NaA) was successfully prepared. Several methods, namely X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Transmission electron microscope (TEM), Brunauer Emmett Teller (BET) and vibrating sample magnetometry (VSM) were used to characterize the adsorbent. A batch experiment was conducted to study the Cu²⁺ adsorption capacity of Fe₃O₄@zeolite NaA at different pH values, contact time, initial Cu²⁺ concentration and adsorbent does. It is found that the saturated adsorption capacity of Fe₃O₄@zeolite NaA on Cu²⁺ is 86.54 mg/g. The adsorption isotherm analysis shows that the adsorption process of Fe₃O₄@zeolite NaA to Cu²⁺ is more consistent with the Langmuir model, suggesting that it is a monolayer adsorption. Adsorption kinetics study found that the adsorption process of Fe₃O₄@zeolite NaA to Cu²⁺ follows the pseudo-second kinetics model, which means that the combination of Fe₃O₄@zeolite NaA and Cu²⁺ is the chemical chelating reaction. Thermodynamic analysis shows that the adsorption process of Fe₃O₄@zeolite NaA to Cu²⁺ is endothermic, with increasing entropy and spontaneous in nature. The above results show that Fe₃O₄@zeolite NaA is a promising Cu²⁺ adsorbent.