Water desalination by forward osmosis: draw solutes and recovery methods – review

ABSTRACT

Water production has become a serious concern nowadays due to many environmental and social factors. Conventional desalination processes are considered as energy-intensive, as energy consumption represents 50–60% of water production cost. As an example, multistage flash evaporation (MSF), requires 19.58–27.25 kWh_e/m³, and reverse osmosis (RO) 1.5–6 kWh_e/m³. Thus, developing forward osmosis (FO), a membrane technology for water desalination considered as a potentially energy-efficient process, has gained growing interest. However, the technology is facing serious limitations concerning the availability of a high-performance draw solution and membrane, which represent the core of the process. In addition to the lack of energy-efficient recoverable draw solutes, as the regeneration process represents the main energy consumption of the overall FO process. In this paper, an updated state of the art of newly developed draw solutes such as deep eutectic solvents, ionic liquids, smart materials, and classical FO draw solutes have been carried out. Finally, FO technology challenges, opportunities, and future prospects have been discussed. Draw solutes have been categorized according to their recovery methods, innovations and draw solutes strengths and limitations have been critically reviewed. The necessity of theoretical energy consumption and water production costs estimation have been outlined, in addition to pilot-scale testing to demonstrate the process feasibility.

GRAPHICAL ABSTRACT

KEYWORDS:

• Draw solute selection
• draw solution’s recovery methods
• desalination
• forward osmosis
• osmotic performance

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Imane Chaoui is holder of a Master degree in Renewable Energies and Energy Efficiency at the Euro-Med University of Fez, Morocco. Imane Chaoui is actually a Ph.D. student working on forward osmosis process and renewable energies at the Mohammadia School of Engineers and the Euro-med University of Fes under joint supervision.

Prof. Souad Abderafi is full Professor at Moroccan School of Engineering, where she received her doctorate (Ph.D.) in Chemical engineering, in March 2003 and promoted as Professor in 2007. Dr Abderafi is currently teaching at Mohammadia Engineering School attached to Mohammed V University in Rabat. Her main research interests are industrial process modelling, biomass valorization and desalination. She is peer reviewer in the International Journal of Elsevier (Renewable Energy, Energy, Solar Energy, Applied Energy). Digital identifier of Abderafi is ResearchGate (https://www.researchgate.net/profile/S_Abderafi), and her full ORCID iD and the link to her public record is https://orcid.org/0000-0001-9534-6941. Dr Abderafi may be reached at [email protected].

Prof. Sébastien Vaudreuil is holder of a Ph.D. in Chemical Engineering from Laval University in Canada. Prof. Vaudreuil has more than 20 years of experience in academic and industrial research. His research interests are oriented towards additive manufacturing and renewable energies, particularly the use of solar thermal energy for industrial purposes. Activities in the field of additive manufacturing cover both the development of new materials and the possible applications of this revolutionary manufacturing technique.

Prof. Tijani Bounahmidi is a Chemical Engineer, in 1977, from Mohammadia School of Engineers in Rabat, Morocco. In 1983, he obtained his Ph.D. in Applied Sciences from the University of Liège, Belgium, in Chemical Engineering. Since 1983 he teaches and does research in Process System Engineering, and in Energy and desalination. He is author or coauthor of a number of publications in international journals, and he is a holder of a patent. In 2006, he was the recipient of innovation award by the Moroccan Network of Technology diffusion. Prof. Bounahmidi is a member of the Hassan II Academy of Science and Technology (Morocco) as correspondent member since 2006 and resident member since 2014. He was vice president of Mohammed V-Agdal- Rabat University, Morocco, from 2005 to 2010 and founder and director of the Innovation Technology Centre in Rabat from 2000 to 2006. Since June 2013 he is Professor at EuroMed University of Fes (Morocco) and vice-president of this university.

ORCID

Imane Chaoui http://orcid.org/0000-0002-2206-262X

Additional information

Funding

The authors would like to thank IRESEN, the Research Institute for Solar Energy and New Energies for the continuing funding. (INSTITUT DE RECHERCHE EN ENERGIE SOLAIRE ET ENERGIES NOUVELLES) [Innoprojet 2015 ECSP-BWFOD].