Novel draw solution for forward osmosis based solar desalination. (15th November 2018)

• Record Type: Journal Article
• Authors: Amjad, Muhammad; Gardy, Jabbar; Hassanpour, Ali; Wen, Dongsheng
• Is Part Of: Applied energy. Volume 230(2018)
• Page Start: 220
• Page End: 231
• Publication Date: 2018-11-15
• Subjects: Forward osmosis -- Nanofluid -- Desalination -- Solar energy -- Osmotic pressure; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2018.08.021
• Languages: English
• ISSNs: 0306-2619

Abstract

Graphical abstract: Highlights: Osmotic pressure and temperature aspects are combined for the first time in novel FO solar desalination. The osmotic pressure is enhanced by 150% higher over the salt solution. Novel draw solution can be easily regenerated using solar energy. An enhancement of 105% in the photothermal efficiency is observed. The novel solar FO process is a potential candidate for solar desalination. Abstract: Forward osmosis (FO) is an emerging technology for water desalination which requires no external force for its operation. The performance of FO for water desalination is dependent on draw solution (DS) that must provide high osmosis pressure, minimum reverse flux and efficient separation of water. This work proposes an innovative concept of energy efficient material as DS having two functions, i.e. high osmotic pressure and efficient absorption of solar energy for the regeneration phase. The potassium functionalised carbon nanofibers (K/CNF) which are highly solar absorptive, are engineered and suspended in triethylene glycol (TEG) aqueous solution with different concentrations to act as a novel DS. The TEG-K/CNF is fully characterised for morphological appearance and thermophysical characteristics before using in FO experiments. It is found that the osmotic pressure and water flux of the novel DS are directly dependent on the concentration of K/CNF and TEG. The draw solution is re-concentrated by evaporating the water aided by the highly solar absorptive K/CNF under simulated solar flux. The vapours are condensed and the quality of product water is found to be comparable with potable water standard. The novel concept proposed in this study has the potential to be used in arid areas where solar energy is abundant to fulfil the potable water needs.