Browsing by Author "Erdem, Arzu"

Now showing 1 - 2 of 2

Development of novel sorbents for the determination of mercury in waters by cold vaporatomic absorption spectrometry
(Izmir Institute of Technology, 2011) Erdem, Arzu; Eroğlu, Ahmet Emin
Mercury is one of the most toxic heavy metal ions to all living organisms. A novel solid support with selective functional groups was developed for mercury sorption from waters prior to its determination by cold vapor atomic absorption spectrometry. The support was prepared by immobilization of several functional groups (amino, mercapto, etc.) on silica. Among the sorbents developed, 3-MPTMS-silica has been shown to be an efficient material for the sorption of mercury species due to its selectivity. Sorption experiments were performed to optimize the necessary parameters and conclusively, sorption pH of 7.0, reaction temperature of 25 oC, sorbent amount of 10.0 mg and shaking time of 30 min were applied throughout the study. Various mineral acids, organic acids, oxidizing agents and sulfur- or nitrogen-containing ligands were tried for the elution of mercury species and 2.0 M TGA was found to offer the maximum desorption. The validity of the method was checked via spike sorption experiments with four different types of water; namely, ultra pure, bottled drinking, tap and sea water. The method worked efficiently (>95%) for all types of water. Permeable reactive barriers, such as zero-valent iron and zero-valent copper were also applied for the removal of mercury species. Similar optimization parameters with 3-MPTMS-silica were also obtained for both sorbents. The method validation was also performed and although sea water is a heavy matrix, high uptake results were achieved for both sorbents.
Use of different gold amalgamation techniques in mercury determination by cold vapor atomic absorption spectrometry
(Izmir Institute of Technology, 2005) Erdem, Arzu; Eroğlu, Ahmet Emin
A novel amalgamation/cold vapor atomic absorption spectrometric system was developed for the determination of Hg(II) concentration in water samples. In the next part, an amalgamation unit utilizing various Au-coated sorbents was constructed and tested in the determination of mercury. Among the new amalgamation materials suggested, gold-coated quartz wool was found to be the most efficient although gold sputter-coated carbon fiber gave also very promising results. Analytical performance of the CVAAS system in terms of sample volume, limit of detection, and without/with amalgamation was also investigated. It was observed that the mercury signal increased with increasing sample volume, as expected. On the other hand, provided that the absolute amount of Hg(II) was kept constant while changing the sample volume, use of amalgamation unit resulted in similar calibration sensitivities. With amalgamation, the linearity and the slope of the calibration plots were not dependant on the sample volume and this property is expected to offer an important advantage since it makes the volume adjustment unnecessary. The limit of detection was also improved with amalgamation. The highest improvement was obtained with 2.0 ml sample volume; the limit of detection was 3.5 times lower (3.5 times better) than that of without amalgamation when 5-times trapping was employed. The results demonstrated that the methodology can be applied to these types of samples directly or after amalgamation, depending on Hg(II) concentration.