Simultaneity comparative evaluation of toluene removal from the air by adsorption and UV semi-degradation-based adsorption procedure

A novel adsorbent was synthesized using a mixture of titanium oxide nanoparticles and ionic liquids (ILs) coated on graphene oxide (TiO₂@NGO/ILs@NGO). This adsorbent was used to remove toluene vapor from the air by continuous gas removal based on the UV photo-degradation-adsorption columns procedure (CGR-UV-PDAC) at 500 ml min⁻¹. In addition, the IL of 1-Benzyl-3-methylimidazolium hexafluorophosphate ([BzMIM] [PF₆]) coated on the NGO was also used for adsorption toluene by the CGR-AC procedure at 200 ml min⁻¹. In a dynamic system, the mixture of toluene in pure air was generated in the chamber and moved to two quartz tubes filled with 200 mg of TiO₂@NGO/ILs@NGO adsorbents (500 ml min⁻¹) and ILs@NGO adsorbents (200 ml min⁻¹). The toluene is semi-degraded into three forms: raw material (CO₂, H₂O), non-degraded, and radical compounds by the TiO₂@NGO at low UV irradiation. The radicals/non-degraded toluene were moved to second quartz tubes with ILs@NGO adsorbent without UV irradiation, and they were adsorbed on its surface by chemical (π–π EDA) and physical interactions. Finally, toluene concentration in the outer line was determined with gas chromatography (GC-FID). Due to the results, the high efficiencies of toluene removal with TiO₂@NGO/IL@NGO and [BzMIM][PF₆]@NGO adsorbents, were achieved at flow rate 500 mL min⁻¹ and 200 mL min⁻¹, respectively (n = 10, 98.5%).