| 초록 |
In order to compensate for increasing demand for lithium, lithium extraction from aqueous lithium sources has been investigated with adsorption technique using adsorbents, such as manganese oxide adsorbent having high capacity and selectivity for lithium ion. The manganese oxide adsorbent can be prepared by extracting lithium from spinel lithium manganese oxide with acid treatment. In order to enhance industrial applicability, easy liquid-adsorbent separation process is required. Therefore, several research groups reported various polymeric supports combined with lithium adsorbents to improve the separation process, but not much study are reported for the adsorbent separable from liquid with external magnetic field. In our study, we suggest new-type lithium adsorbent responsive to external magnetic field, which can be attained with realizing magnetite-lithium manganese oxide composite. Magnetite-lithium manganese oxide composite was fabricated with using redox reaction of Fe2+ on the surface of lithium manganese oxide in basic environment. And this composite was examined via X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), vibrating sample magnetometer (VSM), high resolution-transmittance electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Through the results of these analyses, it was found that magnetite is stably built onto lithium manganese oxide while destroying some portion of lithium manganese oxide crystal. The efforts to reduce the destruction were made with changing the reparation conditions, Li/Mn ratio of lithium manganese oxide, precursor amount, concentration of the solution and etc. in this study. In addition, Li ion adsorption properties were examined on the optimized composite after treating the composite with acid solution. |
