Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Speciation and Atomic Absorption Spectrometric Determination of Cr(III)/Cr(VI) with Resin Derivatized with 7-Dodecenyl-8 Quinolinol (Kelex-100)

Chromium exists in aqueous systems in two different oxidation states, namely Cr(III) and Cr(VI). Wastes discharged from industrial activities may contain various toxic metals including chromium. Chromium metal and related products find wide usage in surface coating anodizing processes, preparation of alloys, chromium plating, leather tanning, battery manufacture, production of heat-resistant materials, dyes, welding operations, catalysis, corrosion control, oxidation, preservation of wooden goods, and various other industrial applications. Cr(III) is accepted to be an essential element for living organisms. It has an important role in the regulation of glucose tolerance factor. As opposed to Cr(III), Cr(VI) may show toxic effects, especially in regard to hepatic, lung, and nephrotoxicity.

Styrene-divinylbenzene (SDB) resin was first derivatized with Kelex-100 (7-dodecenyl-8 quinolinol) known as liquid ion exchanger to obtain the SDB- Kelex 100 chelating resin. Another type of SDB- Kelex 100 resin was obtained by simple impregnation of the ligand onto SDB resin. These two resins were used in the separation, preconcentration, and selective determination of Cr(III) and Cr(VI) species. Reproducible results could not be obtained with the use the former chelating SDB- Kelex 100 resin. On the other hand, using the sorbent prepared by impregnation, Cr(VI) was quantitatively retained in the range of pH 1-3, and Cr(III) at pH 6. All Cr determinations were subsequently made using atomic absorption spectrometry (AAS). For the working pH of specific retention of a given chromium species, the other oxidation state was shown not to quantitatively adsorb. The batch sorption capacities were 12.01 mg g-1 resin for Cr(III) and 121.95 mg g-1 resin for Cr(VI). Since Kelex-100 was a very strong ligand for chelation of all oxidation states of chromium, eluent mixtures of varying concentration of acid, base, and alkaline oxidant were tested in desorption without appreciable success (recovery < 30 %). Due to the irreversible binding of chromium species to the resin, analytical chromium determinations were based on the equilibrium amounts of chromium remaining in the aqueous phase rather than on the amounts retained by the resin. These analytical data were used for the investigation of chromium speciation and preconcentration as a function of various parameters.

YAVAŞÇA Tuğba

Danışman : Yrd. Doç. Dr. Kubilay GÜÇLÜ

Anabilim Dalı : Kimya

Programı : Analitik Kimya

Mezuniyet Yılı : 2009

Tez Savunma Jürisi : Prof. Dr. Reşat APAK

Prof. Dr. Hayati FİLİK

Prof. Dr. Esma TÜTEM

Prof. Dr. İnci SÖZMEZOĞLU

Yrd. Doç. Dr. Kubilay GÜÇLÜ