Extraction and determination of benzene from waters and wastewater samples based on functionalized carbon nanotubes by static head space gas chromatography mass spectrometry

Removal of benzene, as hazardous pollutants from waters and wastewater is a main problem of environment contamination due to high risk factor in human health. In this study, the phenyl sulfonic acid (PhSA) modified carbon nanotubes (CNTs) were used for benzene removal from waters by dispersive micro solid phase extraction method (D- μSPE). Due to adsorption mechanism, the polar–π and π–π electron donor–acceptor interactions was provided between the aromatic ring of benzene with the surface sulfonic acid groups (SO3H) and phenyl ring (-C6H5) of CNTs, respectively. Therefore, 20-100 mg of sorbent, concentration of benzene (0.1–10 mg L^-1), pH (1-12) and contact time (5–120 min) were investigated and optimized for benzene removal from water samples in static system. The concentration of benzene in water was determined by static head space gas chromatography mass spectrometry (SHS-GC-MS). The results showed, the Langmuir- Freundlich (LF) isotherm provided the best fit for benzene sorption. By using the Langmuir model, the maximum adsorption capacity of 157.34 mg g^-1 and 22.86 mg g^-1 was achieved for benzene removal from waters with CNTs@PhSA and CNTs, respectively. The method was validated by certified reference material in waters.