Adsorption Capacity Of Activated Carbon Fiber Research Articles

Adsorption characteristics of nitrate ion by sodium carbonate activated PAN-based activated carbon fiber

In this study, polyacrylonitrile (PAN)-based carbon fiber with high nitrogen content was activated at 800 °C with sodium carbonate and heat-treated at 950 °C to prepare activated carbon fiber (ACF), and the results of nitrate ion adsorption on the prepared ACF are presented. CHN elemental analysis, XPS measurement, and Boehm titration were used to determine the nitrogen content and surface functional groups of ACF. It is discussed that the total amount of nitrogen decreases, whereas quaternary nitrogen (N-Q) increases upon heat treatment. The decrease in adsorption capacity of the prepared activated carbon under different storage conditions is shown. It is observed that the adsorption capacity of nitrate ion at equilibrium pH (pHe) 5 is halved after 5 weeks, and the decrease in adsorption capacity at pHe 3 is suppressed. The adsorption isotherms of the prepared ACF are shown using the Langmuir equation. The effect of pH on the adsorption capacity of the prepared ACF is compared with that of ACF before heat treatment and zinc chloride-activated powdered activated carbon. The adsorption capacity of ACF without heat treatment at 950 °C decreases as the pHe of the solution increases, and the pH of the nitrate solution including ACF after heat treatment is stable at pHe 4–5.

Ozonation of p-Nitrophenol Adsorbed on Activated Carbon Fiber (ACF) and the Change of Textural and Chemical Characteristics of ACF

Ozonation of p-nitrophenol adsorbed on activated carbon fiber (ACF) was conducted in a semiwet atmosphere, and its effect on the textural and chemical characteristics of ACF was examined. The decomposition kinetics of p-nitrophenol followed a pseudo–first-order reaction, and an increase in O3 input enhanced the removal of p-nitrophenol. Ozone slightly etched ACF and resulted in a decrease in the pore volume of ACF, but slightly different changes in pore diameter also occurred on virgin and spent ACF. An increase in the surface oxygen-containing groups (C=O, COOH, etc.) after ozonation might have influence on the adsorption capacity of ACF.

Preparation and Characterization of Activated Carbon Fiber from Paper

Activated carbon fibers (ACFS) with surface area of 1388 m2/g prepared from paper by chemical activation with KOH has been utilized as the adsorbent for the removal of methylene blue from aqueous solution. The experimental data were analyzed by Langmuir and Freundlich models of adsorption. The effects of pH value on the adsorption capacity of ACFS were also investigated. The rates of adsorption were found to conform to the kinetic model of Pseudo-second-order equation with high values of the correlation coefficients (R>0.998). The Langmuir isotherm was found to fit the experimental data better than the Feundlich isotherm over the whole concentration range. Maximum adsorption capacity of 520 mg/g at equilibrium was achieved. It was found that pH played a major role in the adsorption process, higher pH value favored the adsorption of MB.

Influence of Complex Fibrous Media Composition on their Performances for VOC and Particle Removal

Amongst atmospheric pollutants, two major types can be distinguished: airborne particles such as dust, and gaseous compounds such as Volatile Organic Compounds (VOCs). Fibrous filters are commonly used to remove particles while activated carbon beds trap VOCs. In order to obtain a single-stage device as efficient at collecting particles with a size less than 10 μm (PM10) as removing VOCs, prototype fibrous media containing activated carbon fibers (ACF) associated with cellulose fibers (CF), which are non-adsorptive, have been developed. The influence of ACF ratio and the degree of beating of CF on porous structure, mechanical strength and treatment performances of the medium was studied. Experimental results show that an increase in ACF mass ratio increases the inter-fiber porosity and overall adsorption capacity (the intrinsic adsorption capacity of ACF remains constant whatever the composition), but decreases the mechanical strength and particle collection efficiency of the medium. Moreover, an increase in the beating of CF enhances the mechanical strength of the medium and its particle collection efficiency, but decreases its porosity and has no effect on adsorption capacity. Consequently, a medium containing 50 % ACF associated with CF with a low degree of beating (16 °SR) presents the best performance for combined filtration.

ADSORPTION AND DESORPTION OF PHENOL ON ACTIVATED CARBON FIBERS IN A FIXED BED

The application of activated carbon fibers (ACFs) to remove phenol from water is studied. The adsorption capacity of ACFs is favorable and the adsorption isothermal data can be represented by Langmuir-type equation for phenol concentrations changed from 0 to 0.8 kg/m3. The regeneration of ACF adsorbent saturated with phenol in a fixed bed can be achieved by using ethanol or sodium hydroxide solution, respectively, many times with 90% efficiency of regeneration. A mathematical model is applied to evaluate the effects of intraparticle and external mass transfer resistances as well as the axial dispersion on the breakthrough curves. The axial dispersion is confirmed to be the main parameter that controls the adsorption kinetics.

Dominant Properties of Activated Carbon Fiber for the Adsorptive Removal of Trichloroethylene in Liquid Phase.

Contamination of groundwater by volatile chlorinated hydrocarbons is a serious problem today all over our country. In this paper, the adsorptive removal of trichloroethylene (TCE), one of the major contaminants, onto activated carbon fibers (ACFs) in liquid phase was investigated focusing on adsorption isotherms. The adsorption capacity of ACF was larger than that of granular activated carbon (GAC). The adsorption isotherms of TCE onto ACFs and GAC were of Freundlich-type. The amount of TCE adsorbed was inversely proportional to the pore volume, the specific surface area of ACFs, as well as the amount of water adsorbed onto ACFs in gaseous phase. It is considered that the more hydrophobic is the surface of ACF, the larger is the amount of TCE adsorbed onto ACFs in liquid phase.