| Summary: | 碩士 === 大同大學 === 化學工程學系(所) === 104 === Spinel lithium manganese oxide (LMO) material used as a cobalt adsorbent was prepared with solid-state method using lithium carbonate and manganese carbonate as the reactants. Extraction of the Li+ from spinel LMO powder was carried out with 0.3N hydrochloric acid. After Li+ extraction, LMO converts to hydrogen manganese oxide (HMO). Materials were characterized by spectroscopy X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray microanalysis (SEM), Brunauer-Emmett-Teller sorptometer (BET) and thermogravimetric analysis-differential thermal analysis (TGA-DTA).
XRD spectra show that the spinel LMO powder prepared at a calcination temperature of 800oC has higher pure-phase than those prepared at lower calcination temperatures. The HMO powder was characterized by XRD after adsorption reaction, of which peaks slightly shift. Finally, the adsorption performance of spinel sorbent was evaluated by ICP-OES to detect the concentration of Co2+.
The operating conditions such as sorbent dosages, initial concentrations of cobalt ion, temperatures and stirring speeds were investigated in batch system. The adsorption processes followed the Langmuir isotherm and pseudo-second-order equations. In the desorption process, magnet was used to separate Co2+ powder from the mixing powder that should be further investigated.
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