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Altaee A.,University of West of Scotland | Sharif A.,Qatar Energy and Environment Research Institute | Zaragoza G.,CIEMAT | Ismail A.F.,University of Technology Malaysia
Desalination | Year: 2015

PRO and FO coupling with an RO membrane process is proposed to reduce the cost of seawater desalination and the potential for power generation. Three conceptual design configurations, PRO-RO, FO-RO and RO-PRO were evaluated here using standard seawater concentration and impaired water as the draw and the feed solutions respectively. The PRO-RO and RO-PRO designs were evaluated for power generation and seawater desalination while the FO-RO design was proposed for seawater desalination only. The impact of the draw and feed solutions' flow rate and the impaired water TDS on the performance of each design was estimated using pre-developed software. The simulation results showed that the performance of all designs was more sensitive to the increase in the flow rate of draw solution than to the flow rate of feed solution. Furthermore, all designs showed a decrease in membrane flux and recovery rate with increasing the TDS of feed water from 0.2 g/L to 10 g/L as a result of decreasing the net driving force across the membrane and the concentration polarization phenomenon. The FO-RO design produced the lowest RO permeate concentration followed by the PRO-RO and RO-PRO designs respectively. In terms of power generation, the RO-PRO design was more efficient than the PRO-RO design. The FO-RO design exhibited the lowest desalination power consumption followed by the PRO-RO and RO-PRO designs respectively. At 10 g/L feed concentration, the net power consumption in the FO-RO was 9.4% less than that in the PRO-RO which was in turn 5.3% less than that in the RO-PRO design. The estimated cost of the FO/PRO module in the PRO-RO design was 2.2 and 4.3 times higher than that in the FO-RO and RO-PRO designs respectively. Crown Copyright © 2014 Published by Elsevier B.V. All rights reserved.

Mohieldeen Y.E.,Qatar Energy and Environment Research Institute
Water Policy | Year: 2016

This study argues that by mobilising 'social resources', communities in water-scarce, semi-arid areas can not only successfully sustain a livelihood, but they can also play an important role in the water budget of their semi-arid regions. The pastoralist communities in the Darfur region of west Sudan utilise the limited volumes of green - root-zone - water in the soil to rear livestock. They have for centuries developed and adopted a very adaptive management system that has enabled them to utilise the green water of the Nile Basin. The embedded green water in livestock totals more than Sudan's annual share - 18.5 km3 - of the Nile River flow allocated to it by the 1959 Nile Waters Agreement. This study has revealed that this embedded 'virtual water' amounts to 37.6 km3. Results show that this silent, unrecognised, green water has been providing a solution to the water requirements of the Nile economies. It has been suggested that if Western Sudan's livestock were to be produced using fresh/blue water from the Nile, the national water balance of the Sudan would be very seriously impacted and the economy would be much less secure than it has been for the past half century. © IWA Publishing 2016.

Dixit G.,German Electron Synchrotron | Dixit G.,Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy | Chakraborty H.S.,Northwest Missouri State University | Madjet M.E.-A.,German Electron Synchrotron | Madjet M.E.-A.,Qatar Energy and Environment Research Institute
Physical Review Letters | Year: 2013

The effects of confinement and electron correlations on the relative time delay between the 3s and 3p photoemissions of Ar confined endohedrally in C 60 are investigated using the time-dependent local density approximation - a method that is also found to mostly agree with recent time delay measurements between the 3s and 3p subshells in atomic Ar. At energies in the neighborhood of 3p Cooper minimum, correlations with C60 electrons are found to induce opposite temporal effects in the emission of Ar 3p hybridized symmetrically versus that of Ar 3p hybridized antisymmetrically with C60. A recoil-type interaction model mediated by the confinement is found to best describe the phenomenon. © 2013 American Physical Society.

Altaee A.,University of West of Scotland | Sharif A.,Qatar Energy and Environment Research Institute
Desalination | Year: 2015

The current study highlights the advancement in Pressure Retarded Osmosis (PRO) process and covers most recent development in the process applications. The first application of PRO process goes back to 1973 by Sidney Loeb who suggested using the concept of osmotic energy for power generation. In principle, two solutions of different concentrations are separated by semipermeable membrane of, relatively, high water permeability and solute rejection rate. The high-concentration solution is usually known as the draw solution while the low-concentration solution is called the feed solution. The draw solution is pressurized before entering the membrane. Due to the osmotic pressure gradient across the membrane, fresh water transports in the direction of the osmotic pressure gradients resulting in the dilution of the high-concentration solution. After leaving the membrane, the diluted draw solution is depressurized in a turbine system for power generation. Different types of membrane materials and solute gradient resources were proposed and their impact on the performance of PRO process was investigated. In addition to power generation, the hybridization of PRO process with membrane and thermal processes for power generation and seawater desalination is not unusual nowadays. The current study provides a critical review about the recent advancements in the PRO process and research outcomes. © 2014 Elsevier B.V.

Mohammad A.W.,National University of Malaysia | Teow Y.H.,National University of Malaysia | Ang W.L.,National University of Malaysia | Chung Y.T.,National University of Malaysia | And 3 more authors.
Desalination | Year: 2015

Nanofiltration (NF) membranes have come a long way since it was first introduced during the late 80's. With properties in between those of ultrafiltration (UF) and reverse osmosis (RO), NF membranes have been used in many interesting applications especially in water and wastewater treatment and desalination. Other applications include those in pharmaceutical and biotechnology, food and non-aqueous types of application. This review will comprehensively look at the recent advances in NF membranes research. Significant development has taken place in terms of the fundamental understanding of the transport mechanism in NF membranes. This has been translated into predictive modeling based on the modified extended Nernst-Planck equation. Similarly various methods have been used to fabricate improved NF membranes especially through interfacial polymerization incorporating nanoparticles and other additives, UV grafting/photografting, electron beam irradiation, plasma treatment and layer-by-layer modification. New applications were also explored in many industries. However fouling is still a prevalent issue that may hinder successful application of NF membranes. Efforts towards NF fouling prevention and mitigation have also been reported. The review ends with several recommendations on the future prospect of NF membranes research and development. © 2014 Elsevier B.V.

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