Hilal obtained a Bachelor's degree in Chemical Engineering in 1981 followed by three years industrial experience in the oil industry. He obtained a Master of Science degree in Advanced Chemical Engineering in 1985 followed by a PhD in Chemical Engineering in 1988 from Swansea University. He also holds a Postgraduate Certificate in Higher Education from the University of Nottingham in the United Kingdom.

Hilal worked as a lecturer in Chemical Engineering at the University of Nottingham from 2001 to 2003, when he was promoted to a Reader in Chemical and Process Engineering. He was promoted to a Chair Professor in Chemical and Process Engineering (Personal Chair) in December 2004 at the School of Chemical, Environmental and Mining Engineering until August 2010. He moved to Swansea University as the Chair Professor in Water Process Engineering and established the Centre for Water Advanced Technologies and Environmental Research (CWATER). He was also the Head of Chemical and Environmental Engineering at Swansea University.

• Elected Fellow of the Royal Society of Chemistry (FRSC)
• Elected Fellow of the Institution of Chemical Engineers (FIChemE)
• Elected Fellow of the Learned Society of Wales (FLSW)
• Chartered Engineer (CEng) in the UK
• Registered European Engineer (Eur Ing)
• Awarded the 2020 Menelaus Medal ^[5] by the Learned Society of Wales for excellence in engineering and technology
• Awarded a Doctor of Science, Senior Doctorate, from the University of Wales
• Awarded the Kuwait Prize for applied science "Water Resources Development" ^[6]
• Named in the Highly Cited Researchers 2022 list by Clarivate ^[7][8]
• Listed amongst the most Notable Alumni of Swansea University ^[9]
• Listed amongst the most Notable Alumni of University of Wales ^[10]
• Ranked amongst the top scientists in the world ^[11][12]
• Ranked by google scholar amongst the top 10 desalination leaders around the world ^[13]
• Ranked amongst the top 200 in the world ranking for Engineering and Technology ^[14]
• The most cited author (life time) in Desalination ^[15]
• The most cited author in Journal of Water Process Engineering ^[16]
• His extensive knowledge and insights have drawn the interest of international press, especially to inform the public about sustainability, access to clean water, and desalination ^{[17][18][19][20][21][22][23][24][25]}

Hilal has supervised 46 students through their PhDs and more than 70 postdoctoral research fellows, authored over 600 publications including several patents and books.^[26][27][28] His research interests lie broadly in the identification of innovative and cost-effective solutions within the fields of nano-water, membrane technology, and water treatment including desalination, colloid engineering and the nano-engineering applications of AFM. His internationally recognized research has led to the use of AFM in the development of new membranes with optimized properties for difficult separations. His research has produced several breakthrough innovations, including:

• The smallest AFM colloid probe reported in the literature ^[29]
• The first AFM coated colloid probe technique ^[30]
• The first AFM cell probe technique ^[31]
• The first direct measurements of the interaction of single live cells with membrane surfaces ^[32]
• The first direct measurement of the force of adhesion of a single particles with membrane surfaces ^[33]
• The first to show pores on nanofiltration membranes ^[34]
• The first use of the atomic force microscope in meso-scale cavitation studies, development of novel and tailored membranes^[35]
• The development of composite imprinted membranes ^[36]
• The development of self-cleaning membrane for sustainable desalination ^[37]
• Tapping into salty water for agriculture ^[38][39][40]

• Electrically Conductive Membrane Materials and Systems: Fouling Mitigation For Desalination and Water Treatment. ISBN 9780367702069 ^[41]
• Nanofiltration for Sustainability: Reuse, Recycle and Resource Recovery. ISBN 9780367702069 ^[42]
• Osmosis Engineering. ISBN 9780128210161 ^[43]
• Nanofiber membranes for medical, environmental and energy applications. ISBN 9780815387039 ^[44]
• Membrane-based salinity gradient processes for water treatment and power generation. ISBN 9780444639615 ^[45]
• Membrane Characterization. ISBN 9780444637765 ^[46]
• Membrane Fabrication. ISBN 9781482210453 ^[47]
• Boron Separation Processes. ISBN 9780444634542 ^[48]
• Membrane Modification: Technology and Applications. ISBN 9781439866351 ^[49]
• Atomic Force Microscopy and Process Engineering. ISBN 9781856175173 ^[50]
• Nutrients and Coloured Compounds in Wastewater. ISBN 9780443217012 ^[51]
• Water Treatment: Resource Recovery and Sustainability. ISBN 9781032749464

Hilal sits on the editorial boards of a number of international journals, is an advisory board member of several multinational organizations and has served on/consulted for industry, government departments, research councils and universities on an international basis.

• Characterisation of nanofiltration membranes for predictive purposes — use of salts, uncharged solutes and atomic force microscopy, J. Membr. Sci. 126(1) (1997) 91-105.^[52]
• Direct Measurement of Interactions between Adsorbed Protein Layers Using an Atomic Force Microscope, J. Colloid Interface Sci. 197(2) (1998) 348-352.^[53]
• Direct measurement of the force of adhesion of a single biological cell using an atomic force microscope, Colloids and Surfaces A: Physicochemical and Engineering Aspects 136(1) (1998) 231-234. ^[54]
• A new technique for membrane characterisation: direct measurement of the force of adhesion of a single particle using an atomic force microscope, J. Membr. Sci. 139(2) (1998) 269-274. ^[55]
• Characterisation of membrane surfaces: direct measurement of biological adhesion using an atomic force microscope, J. Membr. Sci. 154(2) (1999) 205-212. ^[56]
• Atomic force microscope study of the rejection of colloids by membrane pores, Desalination 150(3) (2002) 289-295. ^[57]
• A study of the tensile properties of liquids in confined spaces using an atomic force microscope, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 459(2039) (2003) 2885-2908.^[58]
• Prediction of permeate fluxes and rejections of highly concentrated salts in nanofiltration membranes, J. Membr. Sci. 289(1) (2007) 40-50. ^[59]
• Surface modified microfiltration membranes with molecularly recognising properties, J. Membr. Sci. 213(1-2) (2003) 97-113.^[60]
• Measurements of Interactions between Particles and Charged Microbubbles Using a Combined Micro- and Macroscopic Strategy, Langmuir 25(9) (2009) 4880-4885.^[61]
• Reduction of nanofiltration membrane fouling by UV-initiated graft polymerization technique. Journal of Membrane Science, 355(1-2) (2010) 133-141.^[62]
• The express monitoring of organic pollutants in water with composite imprinted membranes, J. Membr. Sci. 377(1) (2011) 151-158.^[63]
• Modelling and optimization of coagulation of highly concentrated industrial grade leather dye by response surface methodology. Chemical Engineering Journal, 167 (2011) 77-83.^[64]
• Treatment of high salinity solutions: Application of air gap membrane distillation, Desalination 287 (2012) 55-60.^[65]
• Atomic force microscopy of nanofiltration membranes: Effect of imaging mode and environment, J. Membr. Sci. 389 (2012) 486-498.^[66]
• Produced water treatment: Application of Air Gap Membrane Distillation, Desalination 309 (2013) 46-51.^[67]
• A novel in situ membrane cleaning method using periodic electrolysis, J. Membr. Sci. 471 (2014) 149-154.^[68]
• A combined ion exchange–nanofiltration process for water desalination: I. sulphate–chloride ion-exchange in saline solutions, Desalination 363 (2015) 44-50.^[69]
• Laser Doppler Electrophoresis and electro-osmotic flow mapping: A novel methodology for the determination of membrane surface zeta potential, J. Membr. Sci. 523 (2017) 524-532.^[70]
• Fabrication of antibacterial mixed matrix nanocomposite membranes using hybrid nanostructure of silver coated multi-walled carbon nanotubes, Chemical Engineering Journal 326 (2017) 721-736.^[71]
• Periodic electrolysis technique for in situ fouling control and removal with low-pressure membrane filtration, Desalination 433 (2018) 10-24.^[72]
• Electrically conductive membranes for in situ fouling detection in membrane distillation using impedance spectroscopy, J. Membr. Sci. 556 (2018) 66-72.^[73]
• An integrated fertilizer driven forward osmosis- renewables powered membrane distillation system for brackish water desalination: A combined experimental and theoretical approach, Desalination 471 (2019) 114126.^[74]
• Enhanced performance of direct contact membrane distillation via selected electrothermal heating of membrane surface, J. Membr. Sci. 610 (2020) 118224.^[75]
• Electro-ceramic self-cleaning membranes for biofouling control and prevention in water treatment, Chemical Engineering Journal 415 (2021) 128395.^[76]
• Electrically conductive membranes for contemporaneous dye rejection and degradation, Chemical Engineering Journal 428 (2022) 131184.^[77]
• Intermittent direct joule heating of membrane surface for seawater desalination by air gap membrane distillation, J. Membr. Sci. 648 (2022) 120390.^[78]
• Electrohydrodynamic atomization of CNT on PTFE membrane for scaling resistant membranes in membrane distillation, npj Clean Water (Nature Publication) 6(1) (2023) 15.^[79]
• Enhancing ultrafiltration membrane permeability and antifouling performance through surface patterning with features resembling feed spacers, npj Clean Water (Nature Publication) 6 (2023) 60.^[80]
• Reusable environmentally friendly electrospun cellulose acetate/cellulose nanocrystals nanofibers for methylene blue removal, Journal of Environmental Chemical Engineering 12 (2024) 111788.^[81]