ELECTROSPUN CARBON NANOTUBE-NYLON6 COMPOSITE FIBERS AS SOLID PHASE EXTRACTION SORBENT FOR DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS

Abstract

In this work, electrospun carbon nanotubes-Nylon6 (CNTs-Nylon6) composite fibers were prepared in order to apply as an adsorbent for solid phase extraction (SPE). Adding of CNTs is expected to improve the extraction efficiency of electrospun Nylon6 fibers for determination of polycyclic aromatic hydrocarbons (PAHs). The electrospun CNTs-Nylon6 composite fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and N2 physisorption measurement. The average diameters of obtained fibers ranged from 59 to 117 nm and the BET specific surface area of the electrospun CNTs-Nylon6 composite nanofibers and Nylon6 was 149 and 139 m2/g, respectively. The increase of Nylon6 concentration led to larger fiber diameters. However, increasing the distance of the needle to the collector resulted in smaller fiber diameters. The CNTs aligned along the long axis of Nylon6 nanofibers. The maximum amount of added CNTs was 0.83 %w/w because non-uniform fibers were formed when the amount of CNTs was more than 0.83 %w/w. The obtained electrospun CNTs-Nylon6 composite fibers were examined as SPE disk for determination of PAHs in water. The optimum conditions for extraction of PAHs were using 4.0 mg of electrospun CNTs-Nylon6 composite fibers prepared from 30 %w/v of Nylon6 and 0.83 %w/w of CNTs and eluted with 1 mL of 1:1 (v/v) mixture of acetone and acetonitrile. The percentage recoveries of the extraction of PAHs from 8 µg/L spiked water at optimum conditions were in the range of 56.7-100.8% with the %RSD less than 5. The MOD and MOQ were 0.2-3.0 µg/L and 0.5-6.0 µg/L, respectively. Finally, the membrane was applied for the analysis of PAHs in real water samples. The percentage recoveries of PAHs at 10 µg/L spiked in the samples ranged from 54.2-101.6% which comparable to other methods.