Browsing by Author "Khattab, A."

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An effective removal of organic dyes using surface functionalized cellulose acetate/graphene oxide composite nanofibers
(SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, 2018-07) Aboamera, Nada M.; Mohamed, Alaa; Salama, Ahmed; Osman, T. A.; Khattab, A.
An effective photocatalyst obtained from composite nanofibers CA/GO fabricated by electrospinning technique followed by chemical crosslinking surface modified TiO2 nanoparticles (NPs) was used for removing the organic dyes Indigo carmine (IC) and Methylene blue (MB) from an aqueous solution under UV irradiation light. The crystalline structure and morphologies of CA-GO/TiO2-NH2 composite nanofibers were characterized by SEM, TEM, XRD, and FTIR. The prepared CA-GO/TiO2-NH2 composite nanofibers displayed significantly enhanced photocatalytic activity for photodegradation the organic dyes IC and MB under UV irradiation after 150 and 250 min respectively. The pH value of the solution was studied from 2 to 8 and obtained results showed a clear improvement of photocatalytic activity at pH 2. The results indicated that the activated CA-GO/TiO2-NH2 composite nanofibers functioned as an adsorbent for the removal of IC and MB from aqueous solutions. In addition, the results showed a high adsorption capacity remain up to 65% after five consecutive capacity cycles.
Effects of Increasing Electrodes on CNTs Yield Synthesized by Using Arc-Discharge Technique
(Hindawi Publishing Corporation, 2013) Yousef, Samy; Khattab, A.; Osman, T. A.; Zaki, M.
A new design of fully automatic system was built up to produce multiwalled carbon nanotube (MWCNT) using arc discharge technique in deionized water and extra pure graphite multiple electrodes (99.9% pure). The goal of the experimental research is to determine the yield of CNT in two different cases: (a) single plasma electrodes and (b) multiplasma electrodes, particularly 10 electrodes. The experiments were performed at constant parameters (75 A, 238 V). The obtained CNT was examined by scanning electron microscope (SEM), transmission electron microscope (HRTEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the produced CNT is of type MWCNT, with a diameter of 5 nm, when using multiplasma electrodes and 13 nm when using single plasma electrodes. The yield of MWCNT was found to be 320% higher in case of comparing multielectrodes to that of single plasma electrodes. Under the experimental test conditions, a yield of 0.6 g/hr soot containing 40% by mass nanotube was obtained in case of single plasma electrodes and above 60% in case of multiplasma electrodes.
Fully automatic system for producing carbon nanotubes (CNTs) by using arc-discharge technique multi electrodes
(IEEE, 2012) Yousef, Samy; Khattab, A.; Osman, T. A.; Zaki, M.
The production and industrial applications of carbon nanotubes (CNT) are recently the main concern of research in nanotechnology. CNT exhibit unique properties which have valuable commercial applications ranging from electronics to chemical processes. The main goal of the present paper is to develop the complete design of fully automatic system for producing carbon nanotubes (CNTs) by using deionized water and extra pure graphite multiple electrodes (99.9% pure). The advantage of the designed system is the increase yield of Carbon Nanotubes CNTs within the experimental limitations, through the increase of the number of cathodes and anodes and by using automatic feeding system for the electrodes, considering techniques at lower costs. The results of these experiments were examined by scanning electron microscope (HRSEM) and transmission electron microscope (HRTEM). The results show that the produced CNTs are multi-wall carbon nanotubes with average diameter of 25nm.
Improved mechanical and tribological properties of A356 reinforced by MWCNTs
(Taylor & Francis, 2018) El Shalakany, Abou Bakr; M. Kamel, Bahaa; Khattab, A.; Osman, T. A.; Azzam, B.; Zaki, M.
The objective of this paper is to investigate the effect of Multi-Walled Carbon Nanotubes (MWCNTs) content on microstructure and dry sliding wear behavior of hypo-eutectic A356Al–Si alloy Metal Matrix Nano-Composites (MMNCs). Composites containing 0.5, 1.5, and 2.5 wt.% MWCNTs were prepared by rheocasting technique followed by squeeze casting. Characterization of nanocomposites was done by scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX), dry sliding wear tests were performed in a pin-on-disk wear tester against a steel disk at various speeds and normal loads. Results revealed that a decrease in both wear rate and friction coefficient of the nanocomposites considerably with the increase of MWCNT’s content. The formation of the hard compact transfer layer on the pin surface nanocomposites assisted in increasing the wear resistance of these materials. It is that the transfer layer which was formed under an applied load of 20 N can act as a protective layer and help in reducing the wear rate. The results indicate the nano composites could be used in light-weight applications where moderate strength and wear properties are needed.
Influence Of Nano Grease Composite On Rheological Behaviour
(Journal of Engineering Research and Applications, 2013) Mohamed, Alaa; Khattab, A.; Osman, T.A.; Zaki, M.
The aim of this work is to study the rheological behaviors of carbon nanotubes (CNTs) as an additive on lithium grease at different concentrations. The results indicated that the optimum concentrations of the CNTs was 2 %. These experimental investigations were evaluated with a HAAKE Rheovisco RV20, Penetrometer and Measurement of the dropping point. The results indicated that the shear stress and apparent viscosity increase with the increase of CNTs concentration, penetration and consistency not effect of base grease, and the dropping point increasing about 25%. The microstructure of CNTs and lithium grease was examined by high resolution transmission electron microscope (HRTEM) and transmission electron microscope (TEM).
Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques
(Hindawi Publishing Corporation, 2014) Elshalakany, Abou Bakr; Osman, T. A.; Khattab, A.; Azzam, B.; Zaki, M.
A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs) were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDX). This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt%) of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs.
Visible light photocatalytic activity of PAN-CNTs/ZnO-NH2 electrospun nanofibers
(ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 1/25/2019) Karim, Shrouk A; Mohamed, Alaa; Abdel-Mottaleb, M. M; Osman, T. A; Khattab, A.
The water pollution increases every day due to the increase of the humans needs so a lot of studies were studied for looking the solutions. In this work, we studied the photocatalytic degradation performance of the methylene blue (MB) and the indigo carmine (IC) in an aqueous solution by using the composite nanofiber (PAN-CNTs/ZnO-NH2) under visible light. The electrospinning technique was used to fabricate the PAN-CNTs followed by a chemical crosslinking of ZnO nanoparticles (NPs) on it. FTIR, TEM, SEM and XRD analysis are used to examine the changes of the surface morphology, structure and modification of the fabricated composite nanofiber. This study has proved that PAN-CNTs/ZnO-NH2 get high photodegradation efficiency at a low power intensity (80 lux) and at a short time. A complete degradation has done for the dyes solution after a very short time 29 min and 115 min for IC and MB respectively. There are many factors taking into account during the photodegradation process like the pH of the solution, dyes concentration and the irradiation time. (C) 2018 Elsevier B.V. All rights reserved.