Performance of raw and regenerated multi- and single-walled carbon nanotubes in xylene removal from aqueous solutions

Aims: The ability of raw and recycled multi- and single-walled carbon nanotubes (MWCNT and SWCNT) for xylene adsorption from aqueous solutions was evaluated. Materials and Methods: Batch adsorption experiments were conducted in 110 ml glass bottles. Gas chromatography-mass spectrometry was used for xylene measurement and the carbon nanotube characteristics were evaluated with the help of a transmission electron microscope. Results: With a carbon nanotube dose of 1 g/l, xylene concentration of 10 mg/l, pH 7, and a contact time of 10 minutes, the equilibrium adsorption capacity (q e (mg/g)) of SWCNT was 9.2 mg/g, which was higher than that for MWCNT (8.9 mg/g). The SWCNT revealed a better performance for xylene sorption than the MWCNT. Results of a desorption study showed that xylene adsorbed onto the SWCNT and MWCNT can be easily desorbed at 105 ± 2°C. Conclusions: It is concluded that recycled carbon nanotubes on heating for the first time, show a better performance for xylene adsorption than when they are raw. The SWCNT are efficient as xylene adsorbents in an environmental pollution cleanup.