Potassium hydroxide activated carbons were prepared from Egyptian petroleum cokes with different KOH/coke ratios and
at different activation temperatures and times. The textural properties were determined by adsorption of nitrogen at −196oC.
The adsorption of iodine and methylene blue was also investigated at 30oC. The surface area and the non-micropore volume
increased whereas the micropore volume decreased with the increase of the ratio KOH/coke. Also the surface area and
porosity increased with the rise of activation temperature from 500 to 800oC. Textural parameter considerably increased with
the increase of activation time from 1 to 3 h. Further increasing of activation time from 3 to 4 h was associated with a less
pronounced increase in textural parameters. The adsorption of iodine shows the same trend of surface area and porosity
change exhibited by nitrogen adsorption, with KOH/coke ratio and temperature of activation. Adsorption of methylene blue
follows pseudo-first-order kinetics and its equilibrium adsorption follows Langmuir and D-R models.
Thermal emissivity of nuclear graphite was measured with its oxidation degree. Commercial nuclear graphites (IG-110, PECA, IG-430, and NBG-18) have been used as samples. Concave on graphites surface increased as its oxidation degree increased, and R value (Id/Ig) of the graphites decreased as the oxidation degree increased. The thermal emissivity increased depending on the decrease of the R (Id/Ig) value through Raman spectroscopy analysis. It was determined that the thermal emissivity was influenced by the crystallinity of the nuclear graphite.
In this study, the adsorption of toxic pollutants onto cetyltrimethylammonium kaolin (CTAB-Kaolin) is investigated. The
organo-kaolin is synthesized by exchanging cetyltrimethylammonium cations (CTAB) with inorganic ions on the surface of
kaolin. The chemical analysis, the structural and textural properties of kaolin and CTAB-kaolin were investigated using
elemental analysis, FTIR, SEM and adsorption of nitrogen at −196oC. The kinetic adsorption and adsorption capacity of the
organo-kaolin towards o-xylene, phenol and Cu(II) ion from aqueous solution was investigated. The kinetic adsorption data of
o-xylene, phenol and Cu(II) are in agreement with a second order model. The equilibrium adsorption data were found to fit
Langmuir equation. The uptake of o-xylene and phenol from their aqueous solution by kaolin, CTAB-kaolin and activated
carbon proceed via physisorption. The removal of Cu(II) ion from water depends on the surface properties of the adsorbent.
Onto kaolin, the Cu(II) ions are adsorbed through cation exchange with Na+. For CTAB-kaolin, Cu(II) ions are mainly
adsorbed via electrostatic attraction with the counter ions in the electric double layer (Br−), via ion pairing, Cu(II) ions
removal by the activated carbon is probably related to the carbon-oxygen groups particularly those of acid type. The
adsorption capacities of CTAB-kaolin for the investigated adsorbates are considerably higher compared with those of unmodified
kaolin. However, the adsorption capacities of the activated carbons are by far higher than those determined for
The surface treatment effects of reinforcement filler were investigated based on the dynamic mechanical properties of mutiwalledcarbon nanotubes (MWCNTs)/epoxy composites. The as-received MWCNTs(R-MWCNTs) were chemically modifiedby direct oxyfluorination method to improve the dispersibility and adhesiveness with epoxy resins in composite system. Inorder to investigate the induced functional groups on MWCNTs during oxyfluorination, X-ray photoelectron spectroscopywas used. The thermo-mechanical property of MWCNTs/epoxy composite was also measured based on effects ofoxyfluorination treatment of MWCNTs. The storage modulus of MWCNTs/epoxy composite was enhanced about 1.27 timesthrough oxyfluorination of MWCNTs fillers at 25oC. The storage modulus of oxyfluorinated MWCNTs (OF73-MWCNTs)reinforced epoxy composite was much higher than that of R-MWCNTs/epoxy composite. It revealed that oxygen content ledto the efficient carbon-fluorine covalent bonding during oxyfluorination. These functional groups on surface modifiedMWCNTs induced by oxyfluorination strikingly made an important role for the reinforced epoxy composite.
We investigated the effect of diameter and content of carbon nanotubes (CNTs) on the physical properties of styrenebutadiene rubber (SBR)/CNTs nanocomposites. CNTs-reinforced SBR nanocomposites were prepared by the melt mixing process. CNTs with different diameters were synthesized by the chemical vapor deposition method (CVD). In this work, the mechanical property and other physical properties of SBR/CNTS nanocomposites were discussed as a function of the content and diameter of CNTs.
This cycloaddition of fullerene with methyl azidoacetate in benzene under ultrasonic irradiated condition afforded the
closed [5,6]-bridged aziridinofullerene derivative, which was unusual product of cycloaddition to the 5,6-junction of
fullerene. Its structure was determined by FAB-MS, UV-vis, 1H- and 13C-NMR spectral data. The closed [5,6]-bridged
aziridinofullerene-functionalized gold nanoparticle films were self-assembled using the layer-by-layer method on the
reactive of glass slides functionalized with 3-mercaptopropyltrimethoxysilane. The functionalized glass slides were alternately
soaked in the solution containing closed the [5,6]-bridged aziridinofullerene and 4-aminothiophenoxide/hexanethiolateprotected
gold nanoparticles. The closed [5,6]-bridged aziridinofullerene-functionalized gold nanoparticle films have
grown up to 5 layers depending on the immersion time. The self-assembled nanoparticle multilayer films were characterized
using UV-vis spectroscopy showed that the surface plasmon band of gold at 527 nm gradually became more evident as
successive layers were added to the films.
In this work, the effect of carbon nanofibers (CNFs) addition on physicochemical characteristics of CNFs-reinforced epoxy
matrix nanocomposites was studied. Poly(amide imide) solutions in dimethylformamide were electrospun into webs consisting
of 250±50 nm fibers which were used to produce CNFs through stabilization and carbonization processes. As a result, the
CNFs with average diameter of 200 ±20 nm were obtained after carbonization process. The nanocomposites with CNFs
showed an improvement of thermal stability parameters and fracture toughness factors, compared to those of the specimen
without CNFs, which could be probably attributed to the higher specific surface area and larger aspect ratio of CNFs, resulting
in improving the mechanical interlocking in the nanocomposites. Also, the applied external loading can effectively transfer to
CNFs because strong interactions are resulted between the epoxy matrix and the CNFs.
In this work, the effect of co-carbon fillers on the electrical and mechanical properties of epoxy nanocomposites was investigated. The graphite nanosheets (GNs) and multi-walled carbon nanotubes (MWNTs) were used as co-carbon fillers.
The results showed that the electrical conductivity of the epoxy nanocomposites showed a considerable increase upon an addition of MWNTs when GNs were fixed at 2 wt.%. This indicated that low content GNs formed the bulk conductive network and then MWNTs added were intercalated between the GN layers, resulted in the formation of additional conductive pathway. Furthermore, the flexural strength of the epoxy nanocomposites was enhanced with increasing the MWNT content.
It was probably attributed to the flexible MWNTs compared with rigid GNs, resulted in the enhancement of the mechanical properties.
Henequen fiber was air-stabilized, carbonized, and steam-activated to obtain high surface area activated henequen fiber
(AHF). Thermal behavior of henequen fibers has been studied by TGA. The structural morphology and characteristics
were observed by SEM and BET surface area measurement. The yield of AHF from natural henequen was in the range of
20~25 wt%. Mesopores (2~2.5 nm) were developed on the AHF as the activation temperature was raised up to 700oC, and
the band of mesopore size distribution moved to 15~30 nm when the activation were carried out at 900oC for 30 min. The
specific surface area and the total pore volume were about 1394 m2/g and 1.30 cm3/g, respectively at this activation