High permeable and anti-fouling forward osmosis membranes modified with Grafted Graphene Oxide to Polyacrylamide (GO-PAAm)

Graphene Oxide connected to the Polyacrylamide (GO-PAAm) was synthesized via a simplistic atom transfer radical polymerization (ATRP) reaction and was used in the active layer composition of forward osmosis (FO) membrane as a modifier. The GO-PAAm can improve the hydrophilic characteristic of thin film composite (TFC) membrane, the improvement of hydrophilic property of TFC membranes leading to the better performance of membranes in water permeation. The polyacrylamide was grafted onto Graphene Oxide with ATRP reaction, then the GO-PAAm was immobilized on PES substrate as an active layer, and the compatibility between GO and polymeric membrane matrix was effectively improved with PAAm. The plate structure of graphene oxide rectifies the surface roughness of TFC membranes and prevents fouling. The Membrane surface morphology, Roughness, hydrophilicity were characterized by FESEM, AFM, Contact Angle(CA). Moreover, the characterization of GO and GO-PAAm was conducted with FT-IR, XRD, and also elemental analysis was done by EDS-mapping. Afterward, the effect of the above properties on the separation and water flux and antifouling performance of membranes was investigated. Results have shown that the water flux of the optimal membrane incorporated with GO-PAAm was 40% higher than the virgin TFC membrane. Furthermore, the rejection of NaCl of the modified membrane was 99% higher than that of the intact TFC membrane. In addition, surface modified membranes were showed superior resistance against the fouling. After cleaning flux recovery of the membrane was about 97.6%, while that of the intact TFC membrane was only 79.2%.