Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Lithium recovery from water by granulated pvc pan-titanium type lithium Ion-sieve(01. Izmir Institute of Technology, 2024) İpek, Onur; Özşen, Aslı YükselElektrikli araçların ve enerji depolama sistemlerinin artması nedeniyle lityum tüketimi ve üretim ihtiyacı artış trendindedir. Muadili olmamasından dolayı kritik element olarak sayılan lityumun büyük kısmı su kaynakları içinde çözünmüş haldedir. Bu nedenle bu çalışma katı faz değişimi yöntemi ile sentezlenmiş toz halindeki titanyum bazlı lityum iyon eleği (HTO) immobilize etmek için PVC ve PAN polimerleri ile granüle edilmiştir ve su kütlelerinden lityum geri kazanımı için test edilmiştir. Elde edilen adsorbent, PVC/PAN-HTO, FT-IR, BET, XRD ve SEM analizlerini kullanarak karakterize edilmiştir ve performansı batch adsorpsiyon çalışmalarıyla test edilmiştir. Adsorbentin lityumu tutabilmesi için ortamın bazik olması gerektiği görülmüş ve malzeme için sıfır yük noktası olarak pH 6.03 değeri bulunmuştur. Model lityum çözeltisinde 4 g/L adsorban dozajı kullanılarak pH 12'de %98.7'lik optimum lityum geri kazanım oranı elde edilirken, jeotermal suda aynı adsorban dozajı ile %91.6'lık bir geri kazanım oranı elde edildi. Psödo-birinci ve ikinci derece reaksiyon sabitleri kinetik çalışmalar tarafından ortaya konuldu. 25 °C'deki Langmuir izotermi adsorpsiyon davranışını daha iyi açıklarken maksimum adsorpsiyon kapasitesini 5.59 mg/g olarak sonuçlandırdı. Termodinamik hesaplamalar adsorpsiyonun endotermik ve kendiliğinden olduğunu gösterdi. Üç adsorpsiyon-desorpsiyon döngüsünden sonra lityum geri kazanım oranında önemli bir azalma olmadığı görüldü. Sonuçlar, granül adsorban PVC/PAN-HTO'nun lityum seçici, umut verici ve yeniden kullanılabilir olduğunu göstermektedir.Master Thesis Recovery of Lithium From Aqueous System Using Manganese Oxide Adsorbent With Developed Electrospun Mat Substrate(01. Izmir Institute of Technology, 2023) Akgün, Berk; Ebil, Özgenç; Demir, Mustafa MuammerLithium is used in many fields due to its high energy density and unique electrochemical properties. Recently, there has been a strong increase in demand for lithium, so the extraction of lithium from natural water resources has become a remarkable research topic. One of the most effective methods of separating lithium from natural water sources is adsorption using lithium ion-sieve adsorbents. However, the powdered nature of the adsorbents makes them challenging to process and less recyclable. Recent studies have focused on developing adsorbents using different polymeric materials as substrates or binders. In the thesis, as a new approach, flexible and free-standing polyurethane electrospun mat substrates were produced and combined with λ-MnO2 to extract lithium from aqueous systems, and their lithium removal performance was investigated. After the fabricated mats and λ-MnO2 powder were characterized, the deposition process was performed, and filtration studies were carried out in synthetic lithium solution. Optimum conditions for lithium removal were found as an adsorbent amount of 200 mg, and 200 ppm initial [Li+], and pH 12. In addition, lithium removal performances have been improved by stacking mats and multi-stage filtration processes. Lithium removal reached 76.6% when a 400 ppm lithium solution and an 8-step filtration were used. Lithium removal experiments were performed with salt-lake brine containing high concentrations of various ions and showed that these ions reduced the lithium removal. In the study, PU electrospun mats for λ-MnO2 powder were found to be a promising substrate for lithium removal from aqueous systems.Master Thesis Adsorbent Synthesis for the Recovery of Lithium Water Resources(01. Izmir Institute of Technology, 2022) Kahvecioğlu, Anıl; Yüksel Özşen, Aslı; Yüksel Özşen, AslıLithium 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, AslıThis 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.