Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Adsorbent Synthesis for the Recovery of Lithium Water Resources(01. Izmir Institute of Technology, 2022) Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyLithium is a crucial mineral for the 21st century due to its utilization in a wide range of industries. Lithium demand will increase because of car battery developments and the necessity for power storage. Investigating alternative strategies for resource recovery is the only way to fulfill this unexpected rise properly and sustainably in demand. Adsorption has been discovered to have some technological advantages over other methods. It is considerably less expensive, lacks the chemical resistance present in membranes, lacks the significant electrical demand of electrochemical approaches, as well as the restricted selectivity and challenges in integration into commercial processes. Lithium manganese oxides, also known as lithium ion-sieves, are adsorbents for lithium extraction that have remarkably high selectivity, high adsorption capacity, minimal toxicity, good chemical stability and cheap cost. They are one of the most promising inorganic adsorbents. This research emphasized on the recovery of lithium from water resources through the use of lithium manganese oxide, which were synthesized in laboratory. They were transformed into spherical beads by adding chitosan, followed by crosslinking these beads with epichlorohydrin to increase their adsorption yield, stability, and reusability. Characterization techniques such as SEM, XRD and BET were applied on the adsorbents. Results shows that the adsorbents distributed uniformly, the adsorbent powder was mesoporous, and from the adsorption studies it was found that the adsorbent worked much better in alkaline conditions such as pH 12, optimum adsorbent dosage estimated as 4 g/L and the equilibrium time measured as 10 hours. From the desorption study approximately 95% of Li desorbed for the first cycle, after the second cycle the adsorbent efficiency started to decrease.Master Thesis Functionalized Cellulose-Based Adsorbent for Lithium Recoveryfrom Aqueous Solutions(01. Izmir Institute of Technology, 2021) Nampeera, Jackline; Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; 01. Izmir Institute of Technology; 03.02. Department of Chemical Engineering; 03. Faculty of EngineeringThis study focused on generation of low-cost yet highly effective lithium selective bio-sorbent from olive pruning waste mainly olive branches. Olive branches were treated with NaOH that eliminated non-cellulosic materials and activated hydroxyl groups that inhibit the formation of active sites. Olive branches were then functionalized through homogeneous phosphorylation at 150 ⁰C. POB, NOB, and FOB samples were subjected to SEM, XRD, FTIR, BET, XPS, and TGA to observe the changes in their structure and properties. Factors affecting lithium adsorption were investigated on the synthesized FOB in a batch system and analyzed by ICP-OES. Adsorption isotherms are well fitted to the Freundlich isotherm model than the Langmuir isotherm model which exhibited a maximum adsorption capacity of 6.7 mg/g at 30 ⁰C. Kinetic studies exhibited fast kinetics and equilibrium was attained in 6 minutes while thermodynamic studies showed an exothermic, spontaneous reaction and increased randomness at the interaction interface. Regeneration studies proved the sustainability of FOB with Li+ desorption efficiency of 99.6% in 1.0 M HCl. The synthesized FOB displayed a better degree of column utilization and elution efficiency; 56.8% and 95.8% than Lewatit TP 260; 16.0% and 50.4% respectively in the adsorption column studies performed at room temperature. However, it exhibited a poor breakthrough capacity of 2.1 mg Li/ml sorbent than Lewatit TP 260 with 1.33 mg Li/ml sorbent. Based on all experimental results, the novel functionalized olive branches (FOB) proved a potential lithium selective bio-sorbent and can be applied in the recovery of lithium from its aqueous sources.