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The defense date of the thesis is 2019-02-14
The current date is 2019-03-22
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URN etd-0214119-152020 Statistics This thesis had been viewed 55 times. Download 0 times. Author Cheng-Hsuan Ho Author's Email Address email@example.com Department Chemical Engineering Year 2018 Semester 1 Degree Master Type of Document Master's Thesis Language English Page Count 95 Title Recycling Process of Lithium from Aqueous Solution by Electrochemical Method Keyword lithium manganese oxide (LMO) capacitive deionization hydrogen manganese oxide (HMO) ion exchange electrochemical method lithium electrode electrode lithium electrochemical method ion exchange hydrogen manganese oxide (HMO) capacitive deionization lithium manganese oxide (LMO) Abstract The electrode of the experiment was prepared from commercially available spinel lithium manganese oxide (LiMn2O4, LMO). The spinel LMO powder was treated with 0.5 M hydrochloric acid. After ion exchange, the LMO is transformed to hydrogen manganese oxide (HMO).
The crystal structure of the electrode material is determined via X-ray diffraction spectroscopy (XRD). Cyclic Voltammetry (CV) was used to evaluate electrode stability and redox peaks. In addition, the adsorption and desorption capacity of the electrodes were evaluated by the lithium ion concentration measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results of the study showed that the structure of the electrode did not change much after the preparation procedure.
A novel method for increasing the desorption capacity electrochemically by adding sodium chloride is proposed. The effects of different operating conditions such as initial sodium ion concentration of desorption solution, initial pH of solution, and reaction voltage on the desorption rate of lithium ions were investigated.
It is known from experiments that the desorption capacity obtained was 26.39 mg-Li/g-LMO at initial sodium ion concentration to be of 500 ppm, reaction voltage of 3.0 v, and reaction time of 30 minutes. When the initial concentration of lithium was 500 ppm, the reaction voltage was 2.0 v, and the reaction time was 120 minutes, the obtained adsorption capacity was 6.64 mg-Li/g-HMO. The effect of adsorbing and desorbing lithium increases as the reaction voltage increases. From the experiment of combined mode, the electrode has been cyclically operated at least five times and has a high adsorption/desorption capacity of lithium. The electrochemical method does effectively recover lithium ions from aqueous solutions.
Advisor Committee Rong-Chi Wang - advisor
JIA-MING CHERN - co-chair
Meng-Shun Huang - co-chair
Files Date of Defense 2019-01-31 Date of Submission 2019-02-14