Forward osmosis using highly water dispersible sodium alginate sulfate coated-Fe3O4 nanoparticles as innovative draw solution for water desalination

The remarkable advancement of forward osmosis (FO) as a promising technology for water treatment encounter difficulties due to the synthesis and recovery of a suitable draw solution (DS). The easy recyclability of the draw solution and energy consumption are the critical issues in FO processes. In this work, we have introduced the magnetic core-hydrophilic shell nanoparticles as an efficient draw solute for FO processes. The surface of nanoparticles was modified with sodium alginate sulfate (SAS) as a biocompatible, low toxic and relatively low-cost hydrophilic material. In this regard, the dispersibility and stability of Fe3O4 nanoparticles in aqueous solution was enhanced. The average water flux of 0.06 g mL(-1) Fe3O4@SiO2-SAS was determined as 12.8 and 8.5 L m(-2) h(-1) with a reverse solute flux of 1.48 and 0.23 g m(-2) h(-1) in PRO and FO modes, respectively. Concentrations of 0.05, 0.1 and 0.2 M NaCl have been used as feed solution to study the performance of the DS for desalination process. Moreover, the optimum DS was successfully used for treatment of a real wastewater. Eventually, the synthesized draw solution was recovered by a magnetic field and its reusability was tested. High stability and simple regeneration of DS decreases the cost of water production. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The study introduced magnetic core-hydrophilic shell nanoparticles as an efficient draw solute for forward osmosis processes, with improved dispersibility and stability through surface modification. Results showed that the draw solution performed well in desalination processes and was successfully used for treating real wastewater.