Novel functionalized forward osmosis (FO) membranes for FO desalination: Improved process performance and fouling resistance

The potential of forward osmosis (FO) for water treatment can only be maximized with appropriate FO membranes. In this work, novel FO membranes functionalized with hydrophilic materials carrying both amine and sulfonate or carboxylate groups were synthesized via amidation reaction occurred on thin film composite (TFC) FO membranes. The performance of the newly explored FO membranes was evaluated in FO desalination and antifouling studies. Significant improvement in FO performance was observed for the novel FO membranes, in which the water flux increases more than 19% for the sodium taurine (ST) modified membrane (ST-modified membrane) relative to the pristine TFC FO membrane when pure water and 0.5-2.0 M MgCl2 as the respective feed and draw solutions. Meanwhile, the ST-modified membrane produced a water flux 33% higher than that by the pristine TFC FO membrane in seawater (3.5 wt% NaCl) desalination with 2.0 M MgCl2 as the draw solution, drastically increasing water recovery efficiency. The water flux decline of the ST-modified membrane is 46% lower than that of the pristine membrane with sodium alginate as a foulant. Introducing sulfonate or carboxylate ionic groups onto FO membrane surface is crucial to enhance the membrane antifouling ability and thus improves FO performance, which provides new insight in novel FO membrane exploration.