Mesoporous graphene adsorbents for the removal of toluene and xylene at various concentrations and its reusability

Abstract

As novel technologies have been developed, emissions of gases of volatile organic compounds (VOCs) have increased. These affect human health and are destructive to the environment, contributing to global warming. Hence, regulations on the use of volatile organic compounds have been strengthened. Therefore, powerful adsorbents are required for volatile organic compounds gases. In this study, we used graphene powder with a mesoporous structure to adsorb aromatic compounds such as toluene and xylene at various concentrations (30, 50, 100 ppm). The configuration and chemical composition of the adsorbents were characterized using scanning electron microscopy (SEM), N 2 adsorption-desorption isotherm measurements, and X-ray photoelectron spectroscopy (XPS). The adsorption test was carried out using a polypropylene filter, which contained the adsorbents (0.25 g), with analysis performed using a gas detector. Compared to graphite oxide (GO) powder, the specific surface area of thermally expanded graphene powder (TEGP800) increased significantly, to 542 m 2 g −1 , and its chemical properties transformed from polar to non-polar. Thermally expanded graphene powder exhibits high adsorption efficiency for toluene (92.7–98.3%) and xylene (96.7–98%) and its reusability is remarkable, being at least 91%.

Regeneration of Activated Carbons Spent by Waste Water Treatment Using KOH Chemical Activation

“…The toluene adsorption capacity calculated the integrated area divided by sample weight. In the previous reports [30,31], pore size distribution is also a key parameter to control the toluene adsorption. The toluene is usually adsorbed on the mesopore of ACs, and then diffused into the micropores.…”

“…The toluene adsorption capacities on the ACs were measured using the experimental setup as shown in Figure 1. The surface area, pore size, and functional groups on the surfaces of ACs are considered as key factors to affect adsorption mechanisms, leading to the various toluene adsorption performance [30][31][32][33]. First, the toluene adsorption capacities were largest at a higher surface area: C-AC-A > C-AC-W ≈ H-AC > S-AC, and the calculated adsorption capacity was 0.154, 0.091, 0.100, and 0.033 gtoluene /g-AC , respectively ( Table 5).…”

Removal of benzene vapor from the air based on novel tantalum metal-organic framework (Ta-MOF) adsorbent by gas flow solid-phase interaction before determination by gas chromatography

“…After a specific time, 100-500 microliter air from the vial was extracted and injected into the GC-FID analyzer for determining benzene. The effect of four exposures, times (5, 10, 15, and 20 minutes), the amount of Ta-MOF adsorbent in four amounts (0.5, 1, 1.5, and 2 mg), four different concentration levels (30,50,70, and 100 mg L -1 of benzene) and, two temperatures of 25 and 45°C based on Ta-MOF adsorbent were studied (Fig. 3).…”

“…The CNT has been defined as cylindrical porous with walls made of crystalline graphite layers. Many technologies, such as bio-filter system [26], surface interaction [27], separation [28], adsorption [29,30], and nanocatalyst [31], were used for VOCs removal. In addition, the various adsorbents such as activated carbon based on cellulose acetate [32], carbon nanotube (MWCNTs) [33], Zeolite [34], the graphene-modified by IL [35] were reported for removal benzene and BTX from the air.…”

Atomically Dispersed Y or La on Birnessite-Type MnO2 for the Catalytic Decomposition of Low-Concentration Toluene at Room Temperature

“…3−5 Long-term exposure to VOCs will bring various adverse health impacts, such as tracheitis, pneumonia, high blood pressure, and cerebral hemorrhage and even threaten the life. 2,5 A variety of techniques have been investigated for indoor VOC removal, such as adsorption, 6,7 photocatalytic decomposition, 8,9 nonthermal plasma oxidation, 10,11 and thermal catalytic decomposition. 12−14 Among them, room-temperature catalytic decomposition has advantages in safety, economy, energy conservation, and durability, so it is regarded as a perfect solution for indoor VOC pollution.…”