Purification of benzene-laden air by static adsorption of benzene onto activated carbon prepared from Diplotaxis acris biomass

Activated carbon (AC) was prepared from Diplotaxis acris biomass. The change in the surface functional groups between the biomass raw material and the produced AC was detected using Fourier-transform infrared (FTIR) and Raman spectroscopy. The thermal stability of the prepared AC was determined by using thermogravimetric analysis (TGA). It has a surface area of 40.21 m2/g which gave evidence for its external porous surface. The surface porosity and the graphite properties of the prepared AC were detected by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis, respectively. The amount of adsorbed benzene on the AC surface was determined using a gas chromatograph supported with a flame ionization detector (GC-FID) after extraction in methanol. The adsorption capacity of benzene was 5.4 mg/g at room temperature (25°C), and its removal efficiency reached 95.58% for low benzene concentration (1000 mg/m3). The obtained results were well fitted by the Langmuir isotherm model. The adsorption kinetics of benzene followed the pseudo-second-order kinetic model accompanied by the intra-particle diffusion model. The reuse of the AC samples for three consecutive cycles retained the removal efficiency by more than 75% of its original efficiency. Overall, the study revealed that the prepared AC from Diplotaxis acris biomass has a great potential in the removal of benzene from polluted air.