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Author

Ahmed S. G. Khalil

Other affiliations: IBM, Cairo University, Fayoum University  ...read more
Bio: Ahmed S. G. Khalil is an academic researcher from Egypt-Japan University of Science and Technology. The author has contributed to research in topics: Membrane & Materials science. The author has an hindex of 16, co-authored 70 publications receiving 889 citations. Previous affiliations of Ahmed S. G. Khalil include IBM & Cairo University.


Papers
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TL;DR: In this article, the authors presented experimental results of direct contact membrane distillation (DCMD) with de-ionized water and aqueous salt solutions of NaCl with concentration levels of up to 15 ppt as feed together with an experimentally optimized and validated model for the prediction of the permeate flux in DCMD for GE Aspire Membrane QL 833 (GE Energy).

114 citations

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TL;DR: In this article, three natural dyes were extracted from different fruits and leaves and used as sensitizers for dye-sensitized solar cells (DSSCs) and the degradation in the power conversion efficiencies was monitored over a week.
Abstract: Here, three natural dyes were extracted from different fruits and leaves and used as sensitizers for dye-sensitized solar cells (DSSCs). Chlorophyll was extracted from spinach leaves using acetone as a solvent. Anthocyanin was extracted from red cabbage and onion peels using water. Different characterizations for the prepared natural dyes were conducted including UV-vis absorption, FTIR, and steady-state/time-resolved photoluminescence spectroscopy. Various DSSCs based on the extracted dyes were fabricated. The degradation in the power conversion efficiencies was monitored over a week. The effect of the TiO2 mesoporous layers on the efficiency was also studied. The interfaces between the natural dyes and the TiO2 layers were investigated using electrochemical impedance spectroscopy.

108 citations

Journal ArticleDOI
TL;DR: In this article, the reuse of waste heat recovered from high concentration photovoltaic thermal (HCPVT) systems for saline and brackish water desalination is presented.

82 citations

Journal ArticleDOI
30 Nov 2018
TL;DR: The MoS2/CNT/GNF composite showed a predominant pseudocapacitive charge storage mechanism where the diffusion current was ∼89%, with 88.31% of the resulted capacitance being due to faradic processes.
Abstract: MoS2 is a 2D material that has been widely used in supercapacitor applications because of its layered structure that provides a large surface area and allows for high electric double-layer charge storage. To enhance the cycling stability and capacitance of MoS2, it is usually mixed with carbon materials. However, the dependence of the charge storage mechanism on the structure of the carbon material is still unclear in literature. Herein, the effect of the structure of the carbon material on the charge storage mechanism in 2H flower-shaped MoS2 is investigated in detail. Specifically, 2H MoS2 was mixed with either 8 nm-diameter carbon nanotubes (CNTs) or graphene nanoflakes (GNFs) in different weight ratios. Also, a composite of MoS2, CNTs, and GNFs (1:1:1) was also studied. The charge storage mechanism was found to depend on the structure and content of the carbon material. Insights into the possible storage mechanism(s) were discussed. The MoS2/CNT/GNF composite showed a predominant pseudocapacitive char...

71 citations

Journal ArticleDOI
TL;DR: The polymorph MoS2 showed a well-standing performance in both positive and negative potential windows allowing the fabrication of symmetric supercapacitor devices, and the electrode containing the metallic 1T outperforms those of the 2H and 3R phases in all electrolytes.
Abstract: Supercapacitors have been the key target as energy storage devices for modern technology that need fast charging. Although supercapacitors have large power density, modifications should be done to manufacture electrodes with high energy density, longer stability, and simple device structure. The polymorph MoS2 has been one of the targeted materials for supercapacitor electrodes. However, it was hard to tune its phase and stability to achieve the maximum possible efficiency. Herein, we demonstrate the effect of the three main phases of MoS2 (the stable semiconductor 2H, the metastable semiconductor 3R, and the metastable metallic 1T) on the capacitance performance. The effect of the cation intercalation on the capacitance performance was also studied in Li2SO4, Na2SO4, and K2SO4 electrolytes. The performance of the electrode containing the metallic 1T outperforms those of the 2H and 3R phases in all electrolytes, with the order 1T > 3R > 2H. The 1T/2H phase showed a maximum performance in the K2SO4 electrolyte with a specific capacitance of 590 F g-1 at a scan rate of 5 mV s-1. MoS2 showed a good performance in both positive and negative potential windows allowing the fabrication of symmetric supercapacitor devices. The 1T MoS2 symmetric device showed a power density of 225 W/kg with an energy density of 4.19 Wh/kg. The capacitance retention was 82% after 1000 cycles, which is an outstanding performance for the metastable 1T-containing electrode.

59 citations


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01 Jan 2016

1,633 citations

Journal ArticleDOI
TL;DR: In this article, a review of different desalination units integrated with renewable energy with special emphasis given to solar energy is discussed and problems associated with desalification units and their remedies have been presented.
Abstract: Water plays an important role in all our day to day activities and its consumption is increasing day by day because of increased living standards of mankind. Some regions of the globe are under severe stress due to water scarcity and pollution. The fresh water needs of mankind can be only satisfied if saline water which is available in plenty is converted to potable water by desalination. Desalination industry has shown increased threats of CO2 emissions and severe environmental impacts. Desalination industry can be made sustainable if they are integrated with renewable energy and if proper brine disposal methods are followed. In this review different desalination units integrated with renewable energy with special emphasis given to solar energy is discussed. The problems associated with desalination units and their remedies have been presented. Apart from this some novel methods of desalination process has also been explained. This review will allow the researchers to choose appropriate desalination technology for further development.

481 citations

Journal ArticleDOI
TL;DR: In this article, a green synthesized TiO2 NPs was applied for the first time to testify its potential for the simultaneous removal of chemical oxygen demand (COD) and chromium (Cr) from secondary treated tannery wastewater (TWW).

372 citations

Journal ArticleDOI
TL;DR: The Handbook of Environmental Chemistry as discussed by the authors is a reference source for environmental scientists and decision-makers in industry, government, agencies and public-interest groups, providing sound and solid knowledge about environmental topics from a chemical perspective.

368 citations

Journal ArticleDOI
TL;DR: This work analyzed the tradeoff between the water permeance and the water/NaCl selectivity for TFC membranes gathered from more than 300 published papers, providing a critical tool for the evaluation and benchmarking of future membrane development works in the context of desalination and water reuse.

333 citations