Nidal Hilal
Swansea University, School of Engineering, Faculty Member
Research Interests:
Research Interests:
Research Interests:
Water scarcity as an outcome of global population expansion, climate change, and industrialization calls for new and innovative technologies to provide sustainable solutions to address this alarming issue. Seawater and brackish water are... more
Water scarcity as an outcome of global population expansion, climate change, and industrialization calls for new and innovative technologies to provide sustainable solutions to address this alarming issue. Seawater and brackish water are abundantly available on earth for drinking water and industrial use, and desalination is a promising approach to resolving this global challenge. Recently, the considerable reduction in the cost of desalination has contributed to the growing capacity for global desalination. The desalination technologies that have been deployed worldwide for clean water production can be categorized into two main types: membrane-based and thermal-based. Technological advancement in this field has focused on the reduction of capital and operating cost, particularly the energy consumption of the systems. Seawater and brackish desalination technologies are promising solutions for water shortages.
Research Interests:
We report work in which an Atomic Force Microscope (AFM) is used to deform a liquid film between a colloid sphere and a plane surface. Under some circumstances, when the sphere and the surface are pulled apart rapidly, an unexpected... more
We report work in which an Atomic Force Microscope (AFM) is used to deform a liquid film between a colloid sphere and a plane surface. Under some circumstances, when the sphere and the surface are pulled apart rapidly, an unexpected transient decrease of the sphere-surface separation is recorded. Numerical simulations of cavitation bubble dynamics are used to explain how the growth of a cavitation bubble may result in the development of sufficiently large negative pressures to account for this phenomenon. The results of this study provide evidence in support of a mechanism mooted by Israelachvilli and co-workers that in the cavitation of liquids within confined spaces, the growth of a cavity may be more damaging than its subsequent collapse.
Research Interests:
Research Interests:
Abstract This book brings together a number of engineering process technologies, which all have the principle of osmotic pressure, or rather differences in osmotic pressure between two solutions, at the heart of their operation. For... more
Abstract This book brings together a number of engineering process technologies, which all have the principle of osmotic pressure, or rather differences in osmotic pressure between two solutions, at the heart of their operation. For instance, reverse osmosis requires the application of hydraulic pressure at a magnitude greater than the difference between the feedwater and the permeate water to allow membrane flux to occur against the osmotic pressure gradient. Conversely, in forward osmosis osmotic pressure gradients are harnessed to allow permeate flow from the feedwater to a draw solution of greater osmotic potential. In this chapter, we outline the general principles of osmosis and osmotic pressure, which underpin the technologies discussed in more detail later in this book.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Engineering, Chemical Engineering, Chemistry, Membrane Science, Environmental Monitoring, and 15 moreAtomic Force Microscopy, bisphenol A, Ph, Membrane Separation, Modification, Microfiltration, Composite Material, Filter, Membrane, CHEMICAL SCIENCES, Pollutant, Ionic Strength, Aqueous Solution, Organic Compound, and Measurement System
Research Interests: Engineering, Back Propagation, Neural Network, Desalination, Microfiltration, and 11 moreCeramic, Bentonite, Membrane, CHEMICAL SCIENCES, Ceramic Membrane, Operant Conditioning, Membrane Filtration, Artificial Neural Network, Predictive value of tests, Neural Network Model, and Back Propagation Network
Research Interests:
The efficiency of heavy metal removal from water containing humic substances (HS) has been investigated by means of ultrafiltration. The rejection coefficient of Pb (II), Cu (II), Ni (II) and Co (II) in the presence of humic (HA) and... more
The efficiency of heavy metal removal from water containing humic substances (HS) has been investigated by means of ultrafiltration. The rejection coefficient of Pb (II), Cu (II), Ni (II) and Co (II) in the presence of humic (HA) and fulvic acids (FA) was studied for different ...
Research Interests:
The typical characteristics of membranes can be estimated directly from experimental data. To successfully characterize membranes using such techniques a representative model of the membrane process must be used that is simple enough for... more
The typical characteristics of membranes can be estimated directly from experimental data. To successfully characterize membranes using such techniques a representative model of the membrane process must be used that is simple enough for solution yet detailed enough to capture the key characteristics required. Two cases have been considered where the membrane process has been characterized. The first case is for large pore membranes where slurry filtration or gel layers form on the membrane surface, which is quite typical for microfiltration and ultrafiltration processes. A simple model was described that considers the membrane resistance and the specific cake resistance. The experimental data required are outlined and worked examples are provided that show how to manipulate the data to capture the membrane characteristics. More intensive models that describe the complex microhydrodynamics and interfacial events occurring at the surface and within the small pore membranes are also described. These models are shown to be far more complex and the solution methodologies are not trivial. However, these methods are capable of providing characterization of the pore radius and electrical properties of the membrane at almost atomic scale dimensions. For the case of pore size characterization a simple analytical equation is available and a worked example is provided along with a narrative on best practice. The characterization of electrical properties is far more complicated and involves the solution of nonlinear differential equations. A solution methodology has been explained and tips on best practices have been provided. Overall, membrane characterization using models and experimental data has been demonstrated and can be used for the evaluation of novel membranes or as a guide for the scientist or engineer in the design, scale-up, and optimization of new membrane processes.
Research Interests:
Abstract Ultrafiltration (UF) and nanofiltration (NF) membranes have attracted great research interest to treat dye wastewaters. However, UF membranes suffer from low dye rejection and NF membranes have low salt recovery. There is a... more
Abstract Ultrafiltration (UF) and nanofiltration (NF) membranes have attracted great research interest to treat dye wastewaters. However, UF membranes suffer from low dye rejection and NF membranes have low salt recovery. There is a tradeoff between the dye rejection and salt recovery in the UF and NF membranes. A novel membrane is required for dye rejection with high salt recovery. Herein, we report a novel UF conductive ceramic membrane made from nano-zeolite and carbon nanostructures (CNS) combined with an external electric potential to treat crystal violet (CV) dye/NaCl-Na2SO4 salt solution. The membrane showed trimodal hierarchical porosity, a water contact angle of ≈40°, good flexibility and high electrical conductivity. Voltages from 2 to 15 V were applied to the membrane acting as a cathode in a cross-flow filtration setup. High dye rejections ≈100% with a flux of 210 LMH at a voltage as low as 3 V were achieved. Contemporaneous dye degradation was observed with several intermediate compounds, identified through mass spectroscopy. It was observed that higher potentials produced nitrates/nitrites from organic intermediates as deduced from ion chromatography results. Donnan steric repulsion increased with higher potentials, leading to increased ion transfer resistance for anions and improved permeation for cations. Various permeate properties such as pH and conductivity were monitored, along with high salt recoveries, hence providing a huge advantage of using such a membrane for treating dye wastewaters with selective dye/salt rejection. The versatile properties, together with its facile fabrication process indicates tremendous prospect of zeolite/CNS membranes for multipurpose applications treating wastewaters containing charged molecules and ions.
Research Interests:
Abstract The shortage of clean water sources and increase of demand for fresh water have become as major global challenges not only in industries but also inhuman life. Meanwhile, membrane technology has been extensively noticed due to... more
Abstract The shortage of clean water sources and increase of demand for fresh water have become as major global challenges not only in industries but also inhuman life. Meanwhile, membrane technology has been extensively noticed due to high separation efficiency, energy-saving and environmentally-friendly characteristic. So, development of new membrane is a vital step in advancing of membrane application in water-treatment. This paper presents a comprehensive review on development of high-performance nanofiltration membrane based on nanotechnology for wastewater treatment. Application of new nanomaterials has enabled fabrication of NF-membranes with improved separation properties for pollutants removal from water. Recognizing that conventional membranes are not necessarily suitable for industrial applications and/or process intensifications many attempts were made recently to use of nanomaterials into NF-membranes, aiming to overcome trade-off relationship between flux/selectivity and to improve their stability. So, development of new structured nanomaterial with desirable properties is one of most crucial research topics for membrane researchers. Accordingly, an overview on different methods to design of advanced nanomaterial presented that allow us to overcome their inherent problems in membranes fabrication such as agglomeration, defects formation, insufficient pores’ tuning, poor active sites and anti-fouling properties; however, selection of appropriate nanomaterials is a challenge of utmost difficulty. Various types of nanomaterials such as zeolites, carbon based, framework (MOF/ZIF/COF), nano-biopolymers and special nanoparticles such as SFNPs, SFNCs, POSS, ZCPs, and nickel hydroxide nanosheet are presented and their roles in NF-transport are discussed as well as strategies for surface modification of nanoparticles to promoting their surface charges density. Moreover, fabrication methods of nano enhanced NF-membranes including layer by layer assembly, hollow fiber spinning, electrospinning of nanofibers, construction of thin-film nanocomposite besides blending, co-polymerization; cross-linking and grafting techniques are discussed. A proper view for selection of appropriate nanoparticles in membrane fabrication is offered while considering types of pollutants to be removed.
Research Interests:
Abstract Membrane fouling is a major drawback in membrane-based separation processes. In this work, periodic electrolytic membrane cleaning was used for the first time on ceramic-based electrically conductive membranes made from... more
Abstract Membrane fouling is a major drawback in membrane-based separation processes. In this work, periodic electrolytic membrane cleaning was used for the first time on ceramic-based electrically conductive membranes made from nano-zeolite and carbon nanostructures (CNS). Highly conductive nano zeolite/CNS, hydrophilic microfiltration membranes were fabricated through vacuum filtration, with PVDF as a binder for improved mechanical strength. Membrane cross-section revealed a uniform nano-zeolite distribution within the CNS. The membrane was subjected to periodic electrolysis during the filtration of yeast and sodium alginate (SA) as model foulants. High flux recoveries were obtained, with flux increasing to 95% and 90% for yeast and SA after the first cycle compared to without electrolysis. Subsequent increase in flux was observed thereafter each cleaning cycle reducing the concentration boundary layer. The composite membrane possessed high electrical conductivity and good electrocatalytic behavior for hydrogen evolution, which enabled membrane surface cleaning through the generation of hydrogen bubbles which led to the sweeping away of the foulant layer during the electrocatalytic cleaning between each filtration cycle. The membrane also showed good anti-microbial properties with low bacterial proliferation for both gram-positive and gram-negative bacteria. These electro-ceramic self-cleaning membranes hold immense potential in several types of separation processes where ceramic membranes are a choice of material, and where bio-fouling is a predominant factor for flux decline.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT A fluorinated, 6FDA based polyamide–imide is investigated for the purification of CH4 from CO2 and H2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at... more
ABSTRACT A fluorinated, 6FDA based polyamide–imide is investigated for the purification of CH4 from CO2 and H2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at constant annealing time caused transport behavior that does not resemble physical aging. Free volume increased after annealing at 200 °C for 24 h relative to annealing at 150 °C for the same time. CO2 and CH4 permeabilities and diffusivities did not decrease as a result of the higher annealing temperature, and in fact, were shown to increase slightly. A change to the intrinsic microstructure that cannot be described by simple, densification based physical aging is hypothesized to be the reason for this trend. Furthermore, annealing increased CO2 induced plasticization resistance and a temperature of 200 °C was shown to have the greatest effect on plasticization suppression. Annealing at 200 °C for 24 h suppressed pure gas CO2 plasticization up to 450 psia. Fluorescence spectroscopy revealed increased intramolecular charge transfer, which is presumably due to increased electron conjugation over the N-phenyl bond. Additionally, intermolecular charge transfer increased with thermal annealing, as inferred from fluorescence intensity measurements and XRD patterns. 50/50 CO2/CH4 mixed gas permeation measurements reveal stable separation performance up to 1000 psia. Ternary mixed gas feeds containing toluene/CO2/CH4 and H2S/CO2/CH4 show antiplasticization, but more importantly, selectivity losses due to plasticization did not occur up to 900 psia of total feed pressure. These results show that the polyamide–imide family represents a promising class of separation materials for aggressive acid gas purifications.
Research Interests:
Feed spacers are an important component of membrane‐based filtration systems as they promote turbulence and mass transfer during the filtration process—thereby, reducing the membrane fouling and improving the flux. Whereas spacers are... more
Feed spacers are an important component of membrane‐based filtration systems as they promote turbulence and mass transfer during the filtration process—thereby, reducing the membrane fouling and improving the flux. Whereas spacers are used as a separate component in conjunction with membranes, herein, we demonstrate that membrane‐integrated spacers offer superior fouling resistance and hence an improved output flux during filtration. The integrated spacers were fabricated by 3D printing a composite slurry of UV curable resin and polyvinylidene fluoride on the Polyethersulfone‐based ultrafiltration (UF) membrane. After curing under the UV light, the 3D printed spacers showed excellent flexibility and mechanical integrity along with permanent adhesion to the UF membrane. When tested for filtration using humic acid as foulant, the integrated spacer offered significantly reduced fouling and an increased flux as compared with the commercial spacer. Moreover, it was found that the geometr...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Abstract Forward osmosis (FO) is a process driven by differences in osmotic pressure between a feed and draw solution, as opposed to many other membrane processes, such as reverse osmosis (RO), where hydraulic pressure is applied. The FO... more
Abstract Forward osmosis (FO) is a process driven by differences in osmotic pressure between a feed and draw solution, as opposed to many other membrane processes, such as reverse osmosis (RO), where hydraulic pressure is applied. The FO process needs a semipermeable membrane that segregates the feed solution, with relatively low osmotic pressure and a more concentrated draw solution. As the main operating cost for systems such as RO is the energy needed to pump solutions at high pressure, it is generally expected that FO will have much lowered energy costs. Due to water permeation across the membrane, the concentration of the feed solution will increase over time, whereas the draw solution becomes diluted.
Research Interests:
Research Interests:
Research Interests:
Population growth has always been and will remain one of the main drivers of water demand, along with a larger amount of wastewater generation. As a result, the need for technological innovation to enable novel water management cannot be... more
Population growth has always been and will remain one of the main drivers of water demand, along with a larger amount of wastewater generation. As a result, the need for technological innovation to enable novel water management cannot be overstated. In the past decades, membrane separation technologies have widely been used for desalination and water/wastewater treatment applications. Among them, the membrane distillation (MD) process has recently received much more attention due to its various advantages. However, one of the most important challenges in the way of industrialization of MD process is the lack of novel and specific membranes. Nanotechnology can play a vital role in advancing MD membranes for desalination and water treatment. In this regard, Electrospinning technology for fabricating nanofibrous membranes has emerged as a versatile technique with promising features. This chapter discusses newly developed electrospun nanofibrous membranes for enhancing MD processes for desalination and water/wastewater treatment purposes
Research Interests:
Abstract Water scarcity is a global issue that needs to be urgently addressed to alleviate its adverse impacts on social and economic development. Desalination has been touted as an attractive alternative that can sustainably provide... more
Abstract Water scarcity is a global issue that needs to be urgently addressed to alleviate its adverse impacts on social and economic development. Desalination has been touted as an attractive alternative that can sustainably provide freshwater, particularly when there is no better option to augment water supplies. Tremendous research innovations and evolutions have been made to improve desalination processes in various aspects. Hybridization of two of more desalination processes has been recognized as a promising approach to tackle the inherent disadvantages of conventional desalination processes in regards of energy consumption, water productivity and environmental impacts. While there remains a huge demand for thermal-based desalination particularly in the Middle East region, it is timely to provide a review to look into the progresses made in the hybridization of thermal-based desalination processes. The opportunities for further advancement in the hybridization of thermal-based desalination processes are also proposed. The driving forces for the hybridization of these processes include energy saving, increased freshwater production and improved flexibility in tapping renewable energy. The design and configurations, performances and optimizations have been made in the hybridizations of thermal-thermal or thermal-membrane desalination. Thermal-based hybrid desalination system represents the future trend of commercial scale desalination operations.
Research Interests:
Abstract Fouling is major concern in several industries involving separation of heavy oil components such as crude and motor oils. In this work, a novel free-standing, conductive ceramic membrane, made from nanozeolite and carbon... more
Abstract Fouling is major concern in several industries involving separation of heavy oil components such as crude and motor oils. In this work, a novel free-standing, conductive ceramic membrane, made from nanozeolite and carbon nanostructures (CNS) was fabricated. Various nano-zeolite: CNS ratios were studied. The membranes were tested for oil/water separation with oil concentration of 600 ppm using a dead-end filtration setup under an applied vacuum of 70 kPa on the permeate side. The zeolite nanoparticles provide excellent underwater oleophobicity and a hydrophilic interface, resulting in efficient oil/water separation with a high rejection of 98% for crude oil. The role of CNS in the composite membrane is three-fold; acting as a binder for zeolite nanoparticles, to provide flexibility and to make the membrane conductive. The hierarchical membrane structure formed from hydrophilic zeolite nanoparticles embedded with the CNS greatly facilitates the rapid permeation of water with a high flux of ˃400 L/m2 h for oil/water separation. With increasing zeolite composition relative to CNS, membrane separation performance was observed to increase till 60 wt. % zeolite content. However, higher percentage decreased the flux considerably while keeping the oil rejection constant. Membrane repeatability was studied by performing 10 filtration cycles, where a decrease in flux to about 50% was observed by the end of the 5th cycle. The conductive nature of the membrane (electrical conductivity = 4.9 × 103 S/m) allowed periodic electrolysis of the membrane, hence recovering the flux considerably after each cycle, and reaching about 80% by the end of the 10th cycle. This work provides a new way to develop ceramic based self-cleaning membranes which are applicable in various industries where fouling in ceramic membranes is a major drawback.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Membrane charge is fundamental to the separation of ions from a membrane and is a major factor in the separation efficiency of ultrafiltration, nanofiltration, and reverse osmosis membranes. Characterization of the charge properties of... more
Membrane charge is fundamental to the separation of ions from a membrane and is a major factor in the separation efficiency of ultrafiltration, nanofiltration, and reverse osmosis membranes. Characterization of the charge properties of membranes can be performed using a variety of different methods. In this chapter, the electrokinetic phenomena of electrophoresis, electro-osmosis, sedimentation potential, and streaming potential are described. Each of these methods is capable of measuring the zeta potential of the membrane in a given electrolyte solution and has been discussed. The fundamental basis of each of the methods is provided and theoretical descriptions are provided. The streaming potential method is the most commonly employed method for the characterization of membrane charge and this technique is described in detail. Typical commercial equipment is shown and discussed and a set of experimental results is provided to illustrate the methodology.
Research Interests:
Membrane processes are advanced filtration processes that utilize the separation properties of finely porous polymeric or inorganic films. Membrane separations are used in a wide range of industrial processes to separate biological... more
Membrane processes are advanced filtration processes that utilize the separation properties of finely porous polymeric or inorganic films. Membrane separations are used in a wide range of industrial processes to separate biological macromolecules, colloids, ions, solvents, and gases. To design, develop, and model membrane processes, knowledge of the physical properties of the solution to be separated is paramount. These properties influence the choice of membrane and process conditions for optimal use. For liquid-based membrane separations the important properties are particle size, surface charge (or zeta potential), and solution viscosity. In this chapter methods for characterizing solution properties will be discussed.
Research Interests:
Research Interests:
The impending crisis posed by water stress and poor sanitation represents one of greatest human challenges for the 21st century, and membrane technology has emerged as a serious contender to confront the crisis. Yet, whilst there are... more
The impending crisis posed by water stress and poor sanitation represents one of greatest human challenges for the 21st century, and membrane technology has emerged as a serious contender to confront the crisis. Yet, whilst there are countless texts on wastewater treatment and on membrane technologies, none address the boron problem and separation processes for boron elimination. Boron Separation Processes fills this gap and provides a unique and single source that highlights the growing and competitive importance of these processes. For the first time, the reader is able to see in one reference work the state-of-the-art research in this rapidly growing field. The book focuses on four main areas: * Effect of boron on humans and plants* Separation of boron by ion exchange and adsorption processes* Separation of boron by membrane processes* Simulation and optimization studies for boron separation . Provides in one source a state-of-the-art overview of this compelling area . Reviews the environmental impact of boron before introducing emerging boron separation processes . Includes simulation and optimization studies for boron separation processes . Describes boron separation processes applicable to specific sources, such as seawater, geothermal water and wastewater