Papers by Keyword: Activated Carbon Fiber (ACF)

Abstract: Various jute-based activated carbon fibers were prepared by using jute fibers as raw materials, phosphoric acid as activating agent and activated by microwave heating. The effects of phosphoric acid concentration, microwave radiation power and microwave radiation time on the adsorption properties of activated carbon fibers were investigated to obtain optimum preparation conditions. The pore structure analysis of the activated carbon were carried out on a ASAP 2010 Surface Area and Porosimetry Analyzer. Results showed that optimum preparation conditions were phosphoric acid concentration of 4 mol/L, microwave radiation power of 385 W and microwave radiation time of 10 min. The iodine adsorption value of jute-based activated carbon fiber prepared under optimum conditions is 938.54 mg/g, the specific surface area was 1154.91 m2/g, the pore volume was 0.5997 cm3/g and the adsorption average pore diameter was 2.0772 nm. Majority of large holes in JACF prepared under optimum conditions were distributed in the diameter range of 2-4 nm, demonstrating a mesoporous structure.

Abstract: Various jute-based activated carbon fibers were prepared by using jute fibers as raw materials and phosphoric acid as activating agent. The effects of three main factors such as concentration of activating agent, activation temperature and activation time on the yield and adsorptive properties of active carbon fibers were investigated via orthogonal experiments. The surface physical morphology of jute-based activated carbon fiber was also observed by using Scanning Electron Microscope. Results showed that the optimum conditions were phosphoric acid concentration of 4 mol/L, activation temperature of 600 °C and activation time of 1h. The yield, iodine number and amount of methylene blue adsorption of the active carbon fiber prepared under optimum conditions were 37.99 %, 1208.87 mg/g and 374.65 mg/g, respectively.

Abstract: The activated carbon fiber (ACF) was treated by different concentration nitric acid (HNO₃) and hydrogen peroxide (H₂O₂) oxidization to enhance its adsorption capacity to hexavalent chromium (Cr⁶⁺) ion. The adsorption amount and adsorption kinetics of Cr⁶⁺ ion on ACFs, and the surface chemical groups were investigated. The results showed that the modified ACFs with 1% HNO₃ and 10% H²O² had a better adsorption capacity, respectively. The adsorption amount of ACFs was affected strongly solution pH value, and decreased significantly with increasing of the pH value. The adsorption kinetics indicated that the adsorption rates of Cr6+ ion on different modified ACFs were well fitted with the pseudo-second-order kinetic model. After 1% HNO₃ and 10% H₂O₂ modification, respectively, the total acidic oxygen-containing groups on ACFs surface had an increase obviously, which might be enhance the adsorption amount of Cr⁶⁺ ion on ACFs.

Abstract: Activated carbon fibers (ACFs) supported La-S/TiO₂ nanocomposite photocatalyst was successfully prepared by coating-calcining method. The surface morphology, microstructure and optic properties of the sample were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area and UV–Vis diffuse reflectance spectroscopy (UV–Vis). The characteristic results confirmed that La-S/TiO₂ powders were deposited on activated carbon fiber homogeneously, and the micrographic structure and surface properties of ACFs had not been damaged by the deposition process and calcination at high temperatures. Furthermore, anatase-form TiO₂ was uniquely developed even as calcination temperatures reached 700°C. Experiments indicated that the ACFs supported La-S/TiO₂ nanocomposite photocatalyst calcined at 450°C for 2h showed higher photocatalytic activity in photodegradation of phenol aqueous solution than La-S/TiO₂ powder catalyst. The improvement may be explained in terms of synergetic effect on the stronger adsorption ability of ACFs and efficient photocatalytic performance of La-S/TiO₂.

Abstract: High specific surface materials were widely applied in water pollution control, air pollution control and recycling of organic solvents due to their excellent physical and chemical properties such as large specific surface area, redox characteristic, high adsorption and desorption speed and large adsorptive capacity. The characteristics of activated carbon fiber, nanometer titanium dioxide and their applications in environmental protection such as air purification, the treatment of drinking water and industrial wastewater and the recycling of organic solvent were investigated in present work.

Abstract: Nano-TiO2 powders were synthesized by a sol-gel method using tetrabutyl titanate as the precursor, and then the composites of ACF(activated carbon fiber) supported nano-TiO2 was prepared by impregnating method. Tests of the amount of loaded TiO2 showed that three impregnating times was adequate. The Nano-TiO2 powders and composites were characterized by XRD, SEM, and BET surface area method. XRD tests showed that nano-TiO2 powders prepared by this way are anatase phase, and the mean size of the particles is about 11.5nm, when the calcination temperature is 673K. BET results showed that compared with original ACF, the surface area of the composites decreased slightly, indicating the impregnating process did not change the porous structure of original ACF. SEM result indicated that most of the nano-TiO2 particles as the size of 10-20nm were homogeneously dispersed on the surface of ACF.

Abstract: Activated carbon fibers supported TiO₂ nanoparticle photocatalyst was prepared by immersing activated carbon fibers in water suspended with TiO₂ nanoparticles under sonication. X-ray diffraction and scanning electron microscopy were applied to characterize the crystallinity and morphology of the photocatalyst. The photocatalytic activity of the prepared photocatalyst was evaluated by the photodegradation of formaldehyde for indoor air purification. The result showed that the low-concentration formaldehyde in the polluted indoor air could be photocatalytically degraded over the prepared photocatalyst, with the formaldehyde concentration in the product air falling into the standard range that is specified by the Chinese Indoor Quality Standard.

Abstract: PtRu hollow nanospheres catalysts supported on activated carbon fiber (ACF) and carbon nanotubes (CNTs) were simply prepared at room temperature in a homogeneous solution with Co nanoparticles as sacrificial templates. TEM measurements showed that the coreless PtRu nanospheres supported on ACF and CNTs were both from composed 20 to 30 nm with an average diameter of 24 nm. The shells of the nanospheres on ACF composed of PtRu nanocrystals with a size of 5 nm, while those on CNTs were 3 nm. Electrochemical measurements demonstrated that hollow-PtRu/ACF showed a lower oxidation current density towards methanol electroxidation but a better tolerance to poisoning effect than hollow-PtRu/CNTs. The poorer performance of hollow-PtRu/CNTs may be caused by the phase separation.

Abstract: The adsorption of phenol onto activated carbon fiber (ACF) from aqueous solutions were studied. The adsorption isotherms of phenol onto ACF at 298.15 K,303.15 K and 308.15K follow the Freundlich and Langmuir isotherm equation. The Freundlich model was verified to be the best to describe the adsorption data.Values of ∆G⁰ for phenol adsorption onto ACF are-8.549、-7.899 and -7.516 kJ•mol-1 at 298.15,303.15and 308.15K , respectively. The values of ∆H⁰ and ∆S⁰ are -39.30 kJ•mol-1 and -103.3 J.mol-1.k-1, respectively. The adsorption process is spontaneous and exothermic. Negative △S⁰ values suggested the randomness of phenol molecules at solid-liquid interface and an decrease in the degree of freedom of the adsorbed species.

Abstract: The Mn loaded ACF (ACF-Mn), prepared by impregnation method combined with activation method under high temperature, can be second modified. The best second modifiers, modifier concentration and activation time condition for ACF-Mn was determine by orthogonal experiments. The modified ACF was characterized by XRD、SEM、EDS and other ways. The results show that the optimal conditions for the second modification was that at 700°C under the protection of N2 activation for 50 min when the modifier concentration of CuSO4 was 10%. The iodine adsorption value of the second modified ACF is 1605.36 mgg-1, and the content of basic functional groups is 119.86 mmolg-1. The granular Cu, Mn attached to the surface of ACF and significantly increased its crystallinity. This is helpful to increase the surface area and enhance its adsorption properties.