Synthesis of polymer nanocomposites and organic - inorganic hybrids with using of sol -gel technology for determination of volatile water pollutants

The sol-gel process is a wet-chemical technique, widely used recently in the fields of different sciences. In this project, we used sol gel technology to prepare the thermal and mechanical stable nano composite coating for solid phase microextraction (SPME) fibers and used it for determination of some volatile water pollutants. Three type of sol gel nano composite was used for this propose: Polydimethylsiloxane (PDMS), Polyethyleneglycol (PEG) and PEG modified with carbon nanotubes (CNTs) particles. Coating were done on the fused silica fiber as a solid support and prepared fibers were used with homemade SPME holder. In this process, Methyltrimethoxysilane (MTMOS) was selected as precursor and sol gel process was done at acidic condition for catalysis of preparing of three-network polymer. Extraction efficiency of provided fiber was evaluated by use of this fibers for headspace SPME of BTEX and MTBE in water sample. Results showed that Efficiency of extraction with PEG/CNT fiber was approximately 7 times more than PDMS and 3 times more than PEG fiber at the same condition. Result pictures from scanning electron microscope (SEM) also advocated that use of PEG in sol gel polymer provides a very porous coating and use of CNTs particles in sol gel PEG polymer significantly enhance the specific surface area of this coating. All of these three fibers shown good stability at high temperature (more than 300ºC) at injection system of Gas chromatography device due to chemical bond between solid support and coating polymer (compare to 240 ºC for conventional fibers ) and also life time of these fibers is more than 100 times (compared to 20 times for conventional fibers).

کلیدواژه ها:

Sol-gel ، MTMOS ، PDMS ، PEG ، Carbon nanotubes (CNTs) ، SPME ، BTEX ، MTBE