Equilibrium study of benzene, toluene, ethylbenzene, and xylene (BTEX) from gas streams by black pine cones-derived activated carbon

Abstract

Considering environmental emissions, benzene, toluene, ethylbenzene, and xylene (BTEX) are widely used as raw materials in industrial processes. They also affect humans via inhalation, which must be reduced due to their toxicity before further operation. Notably, the leading technologies have tried to remove BTEX emissions with several methods. Continuous innovation of adsorbents is constantly developing in the adsorption mechanism, which has been developed based on waste biomass. Pinus nigra cones is a lignocellulosic raw material that is fast-growing on various soils and found abundant in nature as a precursor. It may be cheaply found available from some natural product vendors. It was used to prepare activated carbon by chemical activation with phosphoric acid (H3PO4), potassium hydroxide (KOH), sulfuric acid (H2SO4), lithium hydroxide (LiOH), zinc chloride (ZnCl2), sodium hydroxide (NaOH) as the activating agents between at 550–850 °C for 2 h. Fourier transforms infrared spectrometer (FT-IR), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), and N2 gas adsorption–desorption analyzer were used for KAS-ACs characterization. The high BTEX adsorption capacities by ZnCl2 activated carbons were slightly higher than (SBET: 1849 m2/g for KAS-AC91, and Vtotal: 0.44 cm3/g) others. ANOVA results show a high correlation for the KAS-ACs production with ZnCl2, and there was a statistically significant difference between the mean of Vmicro (cm3/g) with activation temperatures p-values<0.05. The removal capacities at 5 μg/L have been done to evaluate using Tenax TA tubes were 92, 96, 88, and 94.08% for benzene, toluene, ethylbenzene, and xylene, respectively. The maximum adsorption capacity for benzene, toluene, ethylbenzene, and xylene onto the KAS-AC91 in the following order: Xylenes (181 μg/g)>Toluene (206 μg/g)>Benzene (171 μg/g)>Ethylbenzene(201 μg/g). This suggests that the KAS-AC91 is an efficient BTEX adsorbent and represents a promising attempt to enhance BTEX adsorption in indoor air quality.