Ozone functionalized CNT-based filters for high removal efficiency of benzene from aqueous solutions

Abstract

This investigation handles the performance of ozone functionalized commercial multiwalled carbon nanotubes (MWNTs) based filters for benzene removal from aqueous solutions. Room temperature ozone treatment was used to modify and functionalize the surface of MWNTs and enhance its adsorption property. The enhancement of oxygen content as well as functional groups was confirmed by Fourier Transform Infrared and Dispersive Electron x-rays Spectroscopy. These functional groups in ozone treated MWNTs filters were found to play a pivotal role to remove benzene from aqueous solutions. It was found that compared to the pristine (P-MWNTs), the ozone functionalized MWNTs (O3-MWNTs) have a lower degree of entanglement and reduced nanotube diameters. Raman spectroscopy was used as a quantitative technique to make concentration measurements of benzene in aqueous solutions. The removal efficiency of benzene by O3-MWNTs could reach 99%. The adsorption capacity of benzene by O3-MWNTs could reach 193 mg/g which is high compared with other adsorbents. Langmuir isotherm model and its characteristic parameters for benzene adsorption were determined. A specific π-π electronic interaction between benzene molecules and higher specific surface area of O3-MWNTs was proposed as the adsorption mechanism. O3-MWNTs filters possess good potential applications for wastewater treatment, and could be used for cleaning up environmental pollution.