Nidal Hilal | Swansea University (original) (raw)
Papers by Nidal Hilal
npj clean water, May 23, 2024
Membrane distillation (MD) is a versatile low-temperature separation process used for desalinatin... more Membrane distillation (MD) is a versatile low-temperature separation process used for desalinating saline solutions with high salt rejection rates. Its current drawbacks include low flux and high energy demand. This study presents localized electrically induced heating using ceramic-coated metallic spacers to improve MD performance. We coated Ni-Cr spacers with MgO via electrolytic deposition and calcination, optimizing for a crack-free protective surface. Smaller wire diameter Ni-Cr exhibited superior heating. When a periodic current of 0.2 A cm −2 was applied, permeate flux increased by 15% although energy consumption only increased by 4%. Continuous supply of high-grade electrical energy added no further performance improvement as compared to periodic application. Our work highlights a spacer-based approach for localized Joule heating in MD systems without compromising membrane structure, while exploring coating systems to protect conductive spacers and optimizing schemes for electrically controlled performance.
Desalination, Feb 1, 2018
Novel hybrid nanostructures (HNS) comprising of a mussel-inspired polymer coated metal/metal oxid... more Novel hybrid nanostructures (HNS) comprising of a mussel-inspired polymer coated metal/metal oxide (M/MO)-carbon nanotubes (CNTs), were successfully synthesised and used to fabricate Thin Film Nanocomposite (TFN) membranes for desalination applications. For comparison, four different M/MO (Aluminium oxide-Al2O3, Iron oxide-Fe2O3, Titanium dioxide-TiO2 and Silver-Ag) nanoparticles (NPs) were in situ synthesized/loaded on the surface of CNTs, and the resultant HNS were further coated with a thin polymeric film of polydopamine (PDA)., An intermediate layer of HNS was then deposited between a PES substrate membrane and an interfacial polymerization (IP) process was carried out to render a polyamide (PA) thin layer on the intermediate layer. Both HNS and TFN were characterized using different characterization tools, including fourier transforms infrared spectroscopy (FTIR), zeta potential (ZP), X-Ray diffraction (XRD), raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), surface hydrophilicity/hydrophobicity, and the performance of nanofiltration (NF) membranes were evaluated against monovalent and divalent salts solutions. The fabricated TFN-NF membranes had higher performance in terms of their permeation characteristics compared to the thin film composite TFC membrane, while maintaining their selectivity against both monovalent and divalent salts solutions with only minor variation depending on the incorporated HNS used to prepare the TFN.
Biotechnology Journal, May 10, 2017
Desalination, Oct 1, 2017
A membrane material that can concurrently provide commercially acceptable levels of water permeab... more A membrane material that can concurrently provide commercially acceptable levels of water permeability, high salt rejection, and of sufficient stability to withstand mechanical and chemical stresses seems to be necessary to guarantee the energy and environmental sustainability of desalination systems and other membrane separation processes. Recent developments in desalination have shown that bio-inspired membranes are moving steadily in this direction. Sustainable desalination via aquaporin-based bio-inspired membranes is elucidated in this paper in terms of recent commercialization exploitation and progress towards real operations. Current large-scale applications, viable opportunities, remaining challenges and sustainability of operations, in terms of comparison with established technologies, are discussed in this paper. The major drawback of aquaporin-based membranes, which has been highlighted repeatedly in recent studies, is the stability of the membranes during real operations. This review is focused on recent solutions provided by scientists towards the mitigation of these problems and commercialization of aquaporin-based membranes.
Desalination, Oct 1, 2017
Desalination, Mar 1, 2017
Electrically enhanced fouling control is increasingly applied to membrane-based separation and re... more Electrically enhanced fouling control is increasingly applied to membrane-based separation and requires conducting membranes with controlled properties. In this work, electrically conductive membranes based on networked cellulose (NC) and carbon nanostructures (CNS) were fabricated via vacuum filtration, followed by drying at 40 °C. The morphology, structure, mechanical and electrochemical properties of these NC-CNS membranes were characterized and compared with CNS membranes. The effect of incorporating NC on the electrocatalytic activity has been analyzed. It is found that networked cellulose helps to decrease the contact angle of water from 105 ° to 73°. It is also found that the improved surface hydrophilicity of CNS-NC membrane assists the regeneration of electrode surface during electrolysis process. Networked cellulose yields a more dense structure with the tensile strength exceeding ten times that of CNS alone. The compaction of pore structure via incorporation of NC translates into promising results with respect to nanofiltration of divalent ions, with a rejection efficiency of 60% for MgSO4 and 47% for CaCl2, while maintaining a high flux ≥ 100 L m-2 h-1 , making them suitable for pretreatment of RO feeds.
Desalination, Nov 1, 2019
The growing water demand across the world necessitates the need for new and improved processes as... more The growing water demand across the world necessitates the need for new and improved processes as well as for a better understanding of existing processes. This level of understanding includes predicting system performance in scenarios that cannot always be evaluated experimentally. Mathematical modelling is a crucial component of designing new and improved engineering processes. Through mathematically modelling real life systems, we gain a deeper understanding of processes while being able to predict performance more effectively. Advances in computational capacity and the ease of assessing systems allow researchers to study the feasibility of various systems. Mathematical modelling studies enable optimization performance parameters while minimizing energy requirements and, as such, have been an active area of research in desalination. In this review, the most recent developments in mathematical and optimization modelling in desalination are discussed with respect to transport phenomena, energy consumption, fouling predictions, and the integration of multiple scaling evolution on heat transfer surfaces has been reviewed. Similarly, developments in optimization of novel reverse osmosis (RO) configurations have been analyzed from an energy consumption perspective. Transport models for membranebased desalination processes, including relatively less understood processes such as nanofiltration and forward osmosis are presented, with recent modifications to allow for different solutes and solutions. Mathematical modelling of hybrid systems integrated with RO has also been reviewed. A survey of the literature shows that mathematical and optimization modelling of desalination processes is an exciting area for researchers in which future scholarship includes coupling of renewable energy systems with desalination technologies, as well as more advanced descriptions of fouling evolution other than that of cake filtration in membrane-based processes.
Journal of Membrane Science, Jun 1, 2018
Online monitoring of fouling in desalination processes enables early and appropriate action for f... more Online monitoring of fouling in desalination processes enables early and appropriate action for fouling control. This study demonstrates the use of Electrochemical Impedance Spectroscopy (EIS) to electrically conductive membranes for online monitoring of fouling by eliminating the need for external electrodes and/or canary cells. Electrically conductive membranes are prepared by incorporation of silica in carbon nanostructures and subsequent fluorination to yield hydrophobic membranes. These membranes are applied to direct contact membrane distillation with 99.9% salt rejection and a flux of 4.3 LMH. EIS is used for online monitoring of inorganic fouling on the membrane surface during the MD process. Impedance spectra taken over a duration of 15 hours indicated that impedance in the low frequency (<100 Hz) region gradually decreased with fouling early on, and increased towards the end. Impedance-based monitoring is more sensitive to changes in the system than monitoring of flux and permeate conductivity. It shows the capability of EIS as a sensitive online monitoring tool for fouling in MD.
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
On fabricating and tailoring membranes for specific applications
npj clean water, May 23, 2024
Membrane distillation (MD) is a versatile low-temperature separation process used for desalinatin... more Membrane distillation (MD) is a versatile low-temperature separation process used for desalinating saline solutions with high salt rejection rates. Its current drawbacks include low flux and high energy demand. This study presents localized electrically induced heating using ceramic-coated metallic spacers to improve MD performance. We coated Ni-Cr spacers with MgO via electrolytic deposition and calcination, optimizing for a crack-free protective surface. Smaller wire diameter Ni-Cr exhibited superior heating. When a periodic current of 0.2 A cm −2 was applied, permeate flux increased by 15% although energy consumption only increased by 4%. Continuous supply of high-grade electrical energy added no further performance improvement as compared to periodic application. Our work highlights a spacer-based approach for localized Joule heating in MD systems without compromising membrane structure, while exploring coating systems to protect conductive spacers and optimizing schemes for electrically controlled performance.
Desalination, Feb 1, 2018
Novel hybrid nanostructures (HNS) comprising of a mussel-inspired polymer coated metal/metal oxid... more Novel hybrid nanostructures (HNS) comprising of a mussel-inspired polymer coated metal/metal oxide (M/MO)-carbon nanotubes (CNTs), were successfully synthesised and used to fabricate Thin Film Nanocomposite (TFN) membranes for desalination applications. For comparison, four different M/MO (Aluminium oxide-Al2O3, Iron oxide-Fe2O3, Titanium dioxide-TiO2 and Silver-Ag) nanoparticles (NPs) were in situ synthesized/loaded on the surface of CNTs, and the resultant HNS were further coated with a thin polymeric film of polydopamine (PDA)., An intermediate layer of HNS was then deposited between a PES substrate membrane and an interfacial polymerization (IP) process was carried out to render a polyamide (PA) thin layer on the intermediate layer. Both HNS and TFN were characterized using different characterization tools, including fourier transforms infrared spectroscopy (FTIR), zeta potential (ZP), X-Ray diffraction (XRD), raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), surface hydrophilicity/hydrophobicity, and the performance of nanofiltration (NF) membranes were evaluated against monovalent and divalent salts solutions. The fabricated TFN-NF membranes had higher performance in terms of their permeation characteristics compared to the thin film composite TFC membrane, while maintaining their selectivity against both monovalent and divalent salts solutions with only minor variation depending on the incorporated HNS used to prepare the TFN.
Biotechnology Journal, May 10, 2017
Desalination, Oct 1, 2017
A membrane material that can concurrently provide commercially acceptable levels of water permeab... more A membrane material that can concurrently provide commercially acceptable levels of water permeability, high salt rejection, and of sufficient stability to withstand mechanical and chemical stresses seems to be necessary to guarantee the energy and environmental sustainability of desalination systems and other membrane separation processes. Recent developments in desalination have shown that bio-inspired membranes are moving steadily in this direction. Sustainable desalination via aquaporin-based bio-inspired membranes is elucidated in this paper in terms of recent commercialization exploitation and progress towards real operations. Current large-scale applications, viable opportunities, remaining challenges and sustainability of operations, in terms of comparison with established technologies, are discussed in this paper. The major drawback of aquaporin-based membranes, which has been highlighted repeatedly in recent studies, is the stability of the membranes during real operations. This review is focused on recent solutions provided by scientists towards the mitigation of these problems and commercialization of aquaporin-based membranes.
Desalination, Oct 1, 2017
Desalination, Mar 1, 2017
Electrically enhanced fouling control is increasingly applied to membrane-based separation and re... more Electrically enhanced fouling control is increasingly applied to membrane-based separation and requires conducting membranes with controlled properties. In this work, electrically conductive membranes based on networked cellulose (NC) and carbon nanostructures (CNS) were fabricated via vacuum filtration, followed by drying at 40 °C. The morphology, structure, mechanical and electrochemical properties of these NC-CNS membranes were characterized and compared with CNS membranes. The effect of incorporating NC on the electrocatalytic activity has been analyzed. It is found that networked cellulose helps to decrease the contact angle of water from 105 ° to 73°. It is also found that the improved surface hydrophilicity of CNS-NC membrane assists the regeneration of electrode surface during electrolysis process. Networked cellulose yields a more dense structure with the tensile strength exceeding ten times that of CNS alone. The compaction of pore structure via incorporation of NC translates into promising results with respect to nanofiltration of divalent ions, with a rejection efficiency of 60% for MgSO4 and 47% for CaCl2, while maintaining a high flux ≥ 100 L m-2 h-1 , making them suitable for pretreatment of RO feeds.
Desalination, Nov 1, 2019
The growing water demand across the world necessitates the need for new and improved processes as... more The growing water demand across the world necessitates the need for new and improved processes as well as for a better understanding of existing processes. This level of understanding includes predicting system performance in scenarios that cannot always be evaluated experimentally. Mathematical modelling is a crucial component of designing new and improved engineering processes. Through mathematically modelling real life systems, we gain a deeper understanding of processes while being able to predict performance more effectively. Advances in computational capacity and the ease of assessing systems allow researchers to study the feasibility of various systems. Mathematical modelling studies enable optimization performance parameters while minimizing energy requirements and, as such, have been an active area of research in desalination. In this review, the most recent developments in mathematical and optimization modelling in desalination are discussed with respect to transport phenomena, energy consumption, fouling predictions, and the integration of multiple scaling evolution on heat transfer surfaces has been reviewed. Similarly, developments in optimization of novel reverse osmosis (RO) configurations have been analyzed from an energy consumption perspective. Transport models for membranebased desalination processes, including relatively less understood processes such as nanofiltration and forward osmosis are presented, with recent modifications to allow for different solutes and solutions. Mathematical modelling of hybrid systems integrated with RO has also been reviewed. A survey of the literature shows that mathematical and optimization modelling of desalination processes is an exciting area for researchers in which future scholarship includes coupling of renewable energy systems with desalination technologies, as well as more advanced descriptions of fouling evolution other than that of cake filtration in membrane-based processes.
Journal of Membrane Science, Jun 1, 2018
Online monitoring of fouling in desalination processes enables early and appropriate action for f... more Online monitoring of fouling in desalination processes enables early and appropriate action for fouling control. This study demonstrates the use of Electrochemical Impedance Spectroscopy (EIS) to electrically conductive membranes for online monitoring of fouling by eliminating the need for external electrodes and/or canary cells. Electrically conductive membranes are prepared by incorporation of silica in carbon nanostructures and subsequent fluorination to yield hydrophobic membranes. These membranes are applied to direct contact membrane distillation with 99.9% salt rejection and a flux of 4.3 LMH. EIS is used for online monitoring of inorganic fouling on the membrane surface during the MD process. Impedance spectra taken over a duration of 15 hours indicated that impedance in the low frequency (<100 Hz) region gradually decreased with fouling early on, and increased towards the end. Impedance-based monitoring is more sensitive to changes in the system than monitoring of flux and permeate conductivity. It shows the capability of EIS as a sensitive online monitoring tool for fouling in MD.
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
CRC Press eBooks, Mar 14, 2023
On fabricating and tailoring membranes for specific applications