2011 YÜksek lisans tez özetleri

Adsorptıon Of Dye Onto Clinoptılolıte Of Natural And Modified Wıth Gemını Surfactants

Adsorption process is one of the effective separation techniques to remove of organic dyes from industrial waste waters. In the adsorption studies, clays, in their natural and modified forms, are the most widely used adsorbents due to their many desirable properties as high sorption capacity and low cost. The modification of clay surfaces with surfactant increase the adsorption capacity for adsorption of organic pollutants.

Gemini surfactants (GYAMs) are composed of two monomeric surfactant molecules chemically bonded together by a spacer. These materials, show higher surface activity and lower critical micelle concentration (CMC) in comparison to their corresponding monomeric counterparts.

In this study, natural - and GYAM - modified clinoptilolite samples were used as adsorbents. Properties of four GYAMs prepared with tetradecyltrimethyl ammonium bromid (C₁₄H₂₉(CH₃)₃NBr) and spacers having C₄ – C₁₂ chain lengths were characterized using NMR spectroscopy. Adsorbent characteristics were elucidated with XRD and FT-IR techniques. Adsorption of Lanaset Green B which is an acid dye was investigated depending on spacer length of GYAM, solution/adsorbent ratio, contact time, initial dye concentration and temperature using UV – Vis. spectroscopy.

Equilibrium data obtained from different initial concentrations were applied to Freundlich, Langmuir and Dubinin – Radushkevich adsorption isotherm equations. Adsorption results for GYAM modified klinoptilolit well described by Langmuir isotherm in the concentration range of 2x10^-4-1x10^-3 M dye solutions. Thermodynamic parameters evaluated using Langmuir equilibrium constants showed that adsorption processes are exothermic and spontaneous.

Four – region Freundlich isotherms were observed in whole studied concentration range of 2x10^-4-8x10^-3 M at 25^oC whereas they converted into two or one step at higher temperatures. The first and the second regions may be arising from electrostatic interactions of anionic dye with cationic GYAMs whereas the third and the four regions may be attributed to hydrophobic interactions which are reduced with temperature.

Both adsorption capacities and mean energy values estimated from D-R isotherm equation also confirm that adsorption process on GYAM modified surfaces is dominated by strong electrostatic interactions whilst dye loosely bound natural clinoptilolite surface.
  

CAN Ziya

Danışman : Doç. Dr. Erol Erçağ

Anabilim Dalı : Kimya

Programı : Analitik Kimya

Mezuniyet Yılı : 2011

Tez Savunma Jürisi : Doç. Dr. Erol Erçağ

Prof. Dr. Reşat Apak

Prof. Dr. Gülten Atun

Prof. Dr. Adnan Aydın

Doç. Dr. Kevser Sözgen Başkan