Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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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 Lithium Extraction From Geothermal Brine by Adsorption Method With Electrolytic Y-Mno2 Sorbent(Izmir Institute of Technology, 2022) Toprak, Seyra; Demir, Mustafa Muammer; Baba, AlperIn recent years, studies on the recovery of lithium metal have attracted great attention due to its wide application areas, especially in lithium-ion batteries. Recovery of lithium from brines is preferred considering the environmental impacts in mining. The application of manganese oxide sorbents to recover lithium from geothermal brines has been extensively studied as it is a potential source of lithium. In this thesis, adsorption was performed in Tuzla Geothermal Power Plant (TGPP) at 87 °C and 2 bar using a mini-pilot system in the reactor near the reinjection well of the plant to investigate the adsorption performance in field conditions. As a new approach, electrolytic manganese dioxide (γ-MnO2), which is widely used as cathode material in batteries, was used as the sorbent material for lithium and its adsorption/desorption performance was investigated. Batch adsorption experiments were performed in synthetic lithium solution and the optimum working conditions were determined as pH 12, adsorbent concentration of 3 g/L, and initial lithium-ion concentration of 200 mg/L. The highest adsorption capacity of the sorbent in the Langmuir model was found as 9.74 mg/g. The maximum adsorption performance was obtained at 1h adsorption in Tuzla GPP. In the continuation of the study, desorption was carried out in acidic medium with the brine-treated sorbent. Lithium concentration was enriched to around 250 ppm with repetitive desorption studies. Reusability of the sorbent was investigated and the reused sorbent showed almost 40% performance compared to virgin powder. γ-MnO2 was found as a promising sorbent for the separation of lithium from geothermal brines.