Types Of Activated Carbon Fibers Research Articles

Enhanced Adsorption of Gaseous Naphthalene by Activated Carbon Fibers at Elevated Temperatures.

This study utilized activated carbon fibers (ACFs) as adsorbents to investigate the removal efficiency of naphthalene and toluene at elevated temperatures and their competitive adsorption behavior. Three types of ACFs, inlet concentrations of naphthalene (343, 457, and 572 mg·Nm-3), and toluene (2055, 2877, and 4110 mg·Nm-3) were investigated to determine the adsorption capacities of naphthalene and toluene. To study the reaction mechanisms of naphthalene and toluene on the ACFs, the BET, SEM, FTIR, and TGA methods were used to examine the physical and chemical characteristics of ACFs. Results showed ACF-A's superior adsorption capacity for naphthalene that was attributed to its mesoporous structure and hydrophobicity. Adsorption equilibrium studies indicated multilayer adsorption behavior. Competitive adsorption experiments demonstrated the displacement of toluene by naphthalene on ACF-A, highlighting its higher selectivity for naphthalene. Functional group analysis revealed changes in ACF surfaces after naphthalene adsorption, suggesting π-π dispersion and electron donor-acceptor interactions. Overall, this study underscores the importance of pore structure and surface properties in designing ACFs for the efficient adsorption of high-boiling-point organic pollutants.

Activated carbon fibers for efficient VOC removal from diluted streams: the role of surface morphology

The effect of the micropore structure of activated carbon fibers (ACFs) on the adsorption of toluene at low concentration (10–80 ppmv) was studied over two types of ACFs. Both adsorbents presented similar surface chemistry but different porous structure: one ACF was ultramicroporous (d pore < 1 nm) and the other supermicroporous (d pore ~1 to 2 nm). Toluene adsorption isotherms were determined for both ACFs and were found to be consistent with Dubinin–Radushkevich (D–R) model. The toluene adsorption enthalpies calculated from temperature-programmed desorption profiles at temperatures below 330 K were close to the values obtained from D–R equations. Larger adsorption strength was found in the ultramicroporous adsorbent as compared to the supermicroporous one suggesting that the pore shape strongly influences the adsorption mechanism. The adsorbent with a lower specific surface area but narrower micropores could be more efficient at high temperatures than an adsorbent with large pore volume and wider micropores. The findings reported have a big importance for correct choice of material when designing efficient structured adsorbing bed.

Activated carbon fibers for efficient VOC removal from diluted streams: the role of surface functionalities

The effect of surface functionalities, specific surface area and pore size of activated carbon fibers (ACFs) on the adsorption of toluene and acetaldehyde, two volatile organic compounds (VOC), at low concentrations (~80 ppmv) and short contact time (20 ms) has been studied. Two different types of ACFs characterized by low temperature N2 adsorption: ultramicroporous (d pore < 1 nm) and supermicroporous (d pore ~ 1–2 nm) were tested. Both ACFs were effective for the removal of toluene attaining the adsorption capacity as large as 51 wt%. The surface chemistry of ACFs (O-containing functional groups) was characterized by temperature-programmed desorption monitoring the CO/CO2 evolved. Oxidative treatment of ACFs by nitric acid increased the surface concentration of O-groups. This resulted in lower adsorption capacity towards toluene but higher one towards acetaldehyde. This result was rationalized based on different type of VOC interactions with the carbon surface.

Adsorption of SO2 and NO from incineration flue gas onto activated carbon fibers

Activated carbon fibers (ACFs) were used to remove SO2 and NO from incineration flue gas. Three types of ACFs in their origin state and after pretreatment with HNO3, NaOH, and KOH were investigated. The removal efficiencies of SO2 and NO were determined experimentally at defined SO2 and NO concentrations and at temperatures of 150, 200 and 260 degrees C. Experimental results indicated that the removal efficiencies of SO2 and NO using the original ACFs were < 56% and < 27%, respectively. All ACFs modified with HNO3, NaOH, and KOH solution could increase the removal efficiencies of SO(2) and NO. The mesopore volumes and functional groups of ACFs are important in determining the removal of SO2 and NO. When the mesopore volumes of the ACFs are insufficient for removing SO2 and NO, the functional groups on the ACFs are not important in determining the removal of SO2 and NO. On the contrary, the effects of the functional groups on the removal of SO2 and NO are more important than the mesopore volumes as the amount of mesopores on the ACFs is sufficient to remove SO2 and NO. Moreover, the removal efficiencies of SO2 and NO were greatest at 200 degrees C. When the inlet concentration of SO2 increased to 600 ppm, the removal efficiency of SO2 increased slightly and the removal efficiency of NO decreased.