Master Degree / Yüksek Lisans Tezleri

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Access type: Open accessSubject: search.filters.subject.Heavy metals

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  • Master Thesis
    Determination of Cadmium Bound To Whey Proteins by Laser-Induced Breakdown Spectroscopy at Low Pressures
    (2023) Yalçın, Şerife; Yaman, İlayda; Yalçın, Şerife Hanım; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    In this thesis study, a dried-droplet LIBS methodology at reduced pressures for determining cadmium in aqueous media and in biological samples has been developed. With the advantage of the signal enhancement effect at reduced pressures, the optimum pressure for Cd detection was determined. Results were justified with the plasma images taken at different pressures. 100 mbar pressure was found as the optimum for most emission lines of Cd. To find the most suitable substrate onto which analyte droplets will be loaded, silicon wafer-based substrates of different coating types and coating thicknesses were studied. Among them, the c-Si substrate was found to show the highest signal enhancement for Cd detection. The performance of the methodology for quantitative analysis of Cd was shown by standard solutions and certified reference water samples. Calibration curves were constructed, and performance characteristics (limit of detection, accuracy, precision) were evaluated. Detection limits in absolute amounts of 6.8 pg and 1.05 pg were obtained at atmospheric and 100 mbar pressures, respectively. The application studies involve the determination of Cd bound to whey proteins. For this purpose, standard protein (BSA) and whey protein extracted from the milk were incubated in standard Cd solutions for several hours and filtered through cut-off filters via centrifugation. The unreacted cadmium in the filtrate and Cd-bound protein in fraction were analyzed separately. It has been shown that dried-droplet LIBS at reduced pressures is a suitable methodology for identifying and determining Cd and Cd bound to proteins with a picogram amount of detection capability.
  • Master Thesis
    Remediation of Heavy Metals in Top Soils of Aliağa Region
    (2023) Demirtepe, Hale; Ökten, Hatice Eser; Demirtepe, Hale; Ökten, Hatice Eser; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Phytoremediation using energy crops provides the opportunity to achieve soil remediation and bio-based energy production simultaneously. However, there is limited information in the literature comparing the potential of different energy plants to remove multiple heavy metals. In this study, safflower (Carthamus tinctorius), canola (Brassica napus), and common reed plants (Phragmites australis), known as energy crops in the literature, were used to investigate their potential for removing multiple heavy metals in the surface soil of Izmir Aliağa region, the surface soil of Kozak Plateau and a mixture soil. The heavy metal removal efficiencies of plants, heavy metal accumulation in the roots and aboveground parts, bioconcentration factors (BCF), translocation factors (TF), biomass production, and soil properties on heavy metal uptake were investigated. As a result, plants generally produced more biomass in the soil with the highest heavy metal concentration and highest organic matter. More accumulation was observed in the roots of all three plants in the study. When BCF and TF were examined, it was revealed that plants mostly showed phytostabilizer properties for the heavy metals studied. Except for Pb, heavy metal concentrations in soil were reduced as a result of phytoremediation. Additionally, when the three plants were compared, safflower was proposed to be the most suitable plant for phytoremediation due to its high potential for multiple heavy metal remediation and high tolerance to drought. To conclude, phytoremediation using energy crops proved to be a sustainable technique by providing concurrent heavy metal removal and energy production.
  • Master Thesis
    Investigation of the Silicon Nitride Coating Thickness on Silicon Wafer Substrates for Enhanced Sensitivity in Dried Nano-Droplet Analysis by Laser Induced Breakdown Spectroscopy
    (01. Izmir Institute of Technology, 2021) Durkan Kaplan, Dilara; Yalçın, Şerife; Yalçın, Şerife Hanım; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Laser Induced Breakdown Spectroscopy (LIBS) is an atomic emission spectroscopic technique that uses laser beam to generate plasma for detection. Also, LIBS is a fast and non-destructive methodology with the advantage of no sample preparation requirement and easy usage. Surface Enhanced LIBS (SENLIBS) is recently developed version of the LIBS technique that uses some kinds of surface materials for supporting liquids and for the enhancement of LIBS signal intensity. It has been previously shown that silicon nitride coated silicon wafer substrates have some properties to enhance LIBS signal of several metal solutions by dried-droplet analysis methodology. Within the scope of this thesis study, silicon wafers coated with silicon nitride of several thicknesses were utilized for investigating the effect of coating thickness on sensitivity of the LIBS technique for liquids analysis. Heavy metals above a certain concentration have a significant negative impact on the environment and human health. In this context, the chromium, copper and lead metal liquid samples was loaded on 75 nm, 300 nm, 450 nm and 1000 nm silicon nitride coated wafers and dried, then analyzed by LIBS. As a result of this study, it was seen that the 1000 nm coating increased the LIBS signal intensity at the highest degree. The LOD value of the chromium element was improved as 0.56 pg, the lead element as 0.7 pg, and the copper element as 0.42 pg with 1000 nm Si3N4 coated wafers.
  • Master Thesis
    Development of a Fluidic Platform for Automated Analysis of Heavy Metals
    (Izmir Institute of Technology, 2019) Gülmez, Yekta; Bulmuş Zareie, Volga; Tekin, Hüseyin Cumhur; Tekin, Hüseyin Cumhur; Bulmuş, Volga; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Heavy metals are part of Earth’s crust and the significant problem is accumulation of them in the ground waters. They have harmful results to body even they are at low concentration. Arsenic is one of the heavy metals which cause serious health problems such as; cancer, diabetes etc. Most of the developing countries are lack of detecting arsenic amount into drinking water. Therefore, especially in Bangladesh 1 out of 100 people die due to arsenic related cancer. According to World Health Organization, the maximum arsenic concentration in the drinking water must be 10 μg/L but the concentration amount reaches 50 μg/L or more at the developing countries. However, existing methods cannot detect arsenic at this range or the ones that can detect arsenic at the standard have so high prices that developing countries cannot afford. Therefore, the aim of this project is to develop a device for arsenic detection. In this thesis, a microfluidic chip was developed, and gold nanoparticles was used to detect arsenic in samples using absorbance spectroscopy. The detection principle was designed based absorption of arsenic and then gold on thiol-modified surfaces. The different concentration of arsenic samples was injected into microfluidic chip and 1.3 mg/L arsenic concentration could be detected. Then, syringe pump was added to the system and flow applied. As a result, the developed microfluidic chip is able to detect arsenic at 2.2 μg/L.