Browsing by Author "Mohamed, Alaa"

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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.
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).
Phenol and benzoic acid recovery from end-of-life of polysulfone ultrafiltration membranes and its thermochemical kinetic behaviour
(Taylor and Francis Ltd., 2023-05) Yousef, Samy; Eimontas, Justas; Striūgas, Nerijus; Mohamed, Alaa; Praspaliauskas, Marius; Abdelnaby, Mohammed Ali
The remarkable properties of polysulfone (PSF) membranes have contributed to their use in many ultrafiltration applications. Meanwhile, this huge usage of PSF films and its short service life have generated a huge amount of waste PSF films that need to be managed carefully. Within this framework, this is the first research specifically developed to valorize the end-of-life of PSF membranes and convert them into high-value chemical and energy products using pyrolysis treatment. The treatment was performed using a thermogravimetric analyzer (TGA), while the structure and abundance of the phenol and benzoic acid compounds in the generated vapor were determined using Fourier-transform infrared (FTIR) spectroscopy and Gas chromatography-mass spectrometry (GC- MS). Thermogravimetric recorded data at different conditions (5–30°C/min) was subjected to linear and nonlinear models including KAS, FWO, Friedman, Vyazovkin, and Cai to assess the pyrolytic kinetic behavior of PSF films. The films showed higher content of volatile matter (57%), lower NOx emissions (0.321%), and a little bit more SOX emission (6.909%). The GC-MS showed that the pyrolytic gaseous products are rich in phenol (24.3%) and benzoic acid (52.4%) compounds and the highest abundance was achieved at 30°C/min. Whereas activation energies were estimated in the range of 193–240 kJ/mol based on linear kinetic criteria versus 161–163 kJ/mol in the case of nonlinear models, where R2 values (>0.91) indicated perfection. Also, distributed activation energy and independent parallel reaction kinetic models showed a good fit with the TGA-DTG experimental data with the minimum deviation. The study con- firmed the potential of pyrolysis treatment in converting wasted PSF films into a new source for the recovery of phenolic and benzoic acid. ARTICLE HISTORY Received 20 March 2023 Revised 27 April 2023 Accepted 2 May 2023
Photodegradation of Ibuprofen, Cetirizine, and Naproxen by PAN-MWCNT/TiO2-NH2 nanofiber membrane under UV light irradiation
(SPRINGEROPEN, CAMPUS, 4 CRINAN ST, LONDON, N1 9XW, ENGLAND, 2018-12) Mohamed, Alaa; Salama, Ahmed; Nasser, Walaa S.; Uheida, Abdusalam
Background: In this study, the photodegradation of three pharmaceuticals, namely Ibuprofen (IBP), Naproxen (NPX), and Cetirizine (CIZ) in aqueous media was investigated under UV irradiation. The photocatalyst used in this work consists of surface functionalized titanium dioxide (TiO2-NH2) nanoparticles grafted into Polyacrylonitrile (PAN)/multi-walled carbon nanotube composite nanofibers. Surface modification of the fabricated composite nanofibers was illustrated using XRD, FTIR, and SEM analyses. Results: Sets of experiments were performed to study the effect of pharmaceuticals initial concentration (5-50 mg/L), solution pH (2-9), and irradiation time on the degradation efficiency. The results demonstrated that more than 99% degradation efficiency was obtained for IBP, CIZ, and NPX within 120, 40, and 25 min, respectively. Conclusions: Comparatively, the photocatalytic degradation of pharmaceuticals using PAN-CNT/TiO2-NH2 composite nanofibers was much more efficient than with PAN/TiO2-NH2 composite nanofibers.
Pyrolysis behaviour of ultrafiltration polymer composite membranes (PSF/ PET): Kinetic, thermodynamic, prediction modelling using artificial neural network and volatile product analysis
(Elsevier B.V, 2024-04) Yousef, Samy; Eimontas, Justas; Striugas, Nerijus; Mohamed, Alaa; Abdelnaby, Mohammed Ali
This study aims to explore the feasibility of managing ultrafiltration polymer composite membranes (UPCM) waste and converting it into valuable chemicals and energy products using a pyrolysis process. The thermal decomposition experiments were performed on polysulfone (PSF)/polyethylene terephthalate (PET) membranes using thermogravimetric analysis (TG). The vapors generated during the thermochemical process were analyzed under different heating rate conditions using TG-FTIR and GC/MS. In addition, the kinetic and thermodynamic parameters of the pyrolysis process were determined using conventional modeling methods and artificial neural network (ANN) method. The results demonstrated that the PSF/PET feedstock exhibits ahigh volatile matter content (77 % wt.%), which can be completely decomposed up to 600 °C by 79 wt%. While TG-FTIR analysis showed that the released vapors contained aromatic groups and benzoic acid (89.21 wt% at 15˚C/min) as the main GC/MS compound. Moreover, the kinetic analysis demonstrated complete decomposition of the membranes at a lower activation energy (151 kJ/mol). Meanwhile, the ANN model exhibited high performance in predicting the degradation stages of PSF/PET membranes under unknown heating conditions. This approach shows potential for modeling the thermal decomposition of ultrafiltration composite membranes more broadly.
Pyrolysis Kinetic Behavior and Thermodynamic Analysis of PET Nonwoven Fabric
(MDPI AG, 2023-09) Yousef, Samy; Eimontas, Justas; Striugas, Nerijus; Mohamed, Alaa; Abdelnaby, Mohammed Ali
This research aims to maximize polyethylene terephthalate (PET) nonwoven fabric waste and make it as a new source for benzoic acid extraction using a pyrolysis process. The treatment was performed using a thermogravimetric analyzer (TGA) and released products were characterized using FTIR spectroscopy and gas chromatography–mass spectrometry (GC–MS). The pyrolysis kinetic and thermodynamic behavior of PET fabric was also studied and simulated using different linear and nonlinear models. The results show that the PET fabric is very rich in volatile matter (80 wt.%) and can completely degrade under 490 ◦C with a weight loss of 84%. Meanwhile, the generated vapor was rich in the carbonylic C=O functional group (FTIR), and the GC–MS analysis concluded that benzoic acid was the major compound with an abundance of 75% that was achieved at the lowest heating rate (5 ◦C/min). The linear kinetic results showed that PET samples had an activation energy in the ranges of 193–256 kJ/mol (linear models) and ~161 kJ/mol (nonlinear models). The thermodynamic parameters, including enthalpy, Gibbs free energy, and entropy, were estimated in the ranges of 149–250 kJ/mol, 153–232 kJ/mol, and 256–356 J/mol K, respectively. Accordingly, pyrolysis treatment can be used to extract benzoic acid from PET fabric waste with a 134% increase in the benzoic acid abundance that can be recovered from PET bottle plastic waste.
Rheological Behavior of Carbon Nanotubes as an Additive on Lithium Grease
(Hindawi Publishing Corporation, 2013) Mohamed, Alaa; Ahmed Khattab, Aly; Abdel Sadek Osman, Tarek; Zaki, Mostafa
The rheological behaviors of carbon nanotubes (CNTs) as an additive on lithium grease at different concentrations were examined under various settings of shear rate, shear stress, and apparent viscosity. The results indicated that the optimum content of the CNTs was 2%. These experimental investigations were evaluated with a Brookfield Programmable Rheometer DV-III ULTRA. The results indicated that the shear, stress and apparent viscosity increase with the increase of CNTs concentration. The microstructure of CNTs and lithium grease was examined by high resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM). The results indicated that the microscopic structure of the lithium grease presents a more regular and homogeneous network structure, with long fibers, which confirms the rheological stability.
Tribological Behavior of Carbon Nanotubes as an Additive on Lithium Grease
(Journal of Nanotechnology, 2013) Mohamed, Alaa; Khattab, Aly; Osman, Tarek; Zaki, Mostafa
Carbon nanotubes (CNTs) with 10 nm average diameter and 5 μm in length were synthesized by electric arc discharge. The morphology and structure of CNTs were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray powder diffraction. The tribological properties of CNTs as an additive on lithium grease were evaluated with a four ball tester. The results show that the grease with CNTs exhibit good performance in antiwear (AW) and decrease the wear scare diameter (WSD) about 63%, decrease friction reduction about 81.5%, and increase the extreme pressure (EP) properties and load carrying capacity about 52% with only 1% wt. of CNTs added to lithium grease. The action mechanism was estimated through analysis of the worn surface with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results indicate that a boundary film mainly composed of CNTs, Cr, iron oxide, and other organic compounds was formed on the worn surface during the friction process.
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.