Fabrication and Surface Modification of PES-Based Nanofiltration Membrane Using Polymethyl Methacrylate/Graphene Oxide Nanoplates

Hypothesis: 

first, poly ether sulfone (PES)-based nanofiltration (NF) membranes were prepared through the phase inversion-immersion precipitation technique. Then, the surface of the membranes made of polymethyl methacrylate (PMMA)-graphene oxide nanoplates (GO NPs) was modified using dip-coating technique. The effect of the active coating layer on the morphology, physical-chemical properties, and antifouling performance and separation ability to remove metal ions from wastewater was studied.

The properties of prepared membranes were studied by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analysis.  Also, the effect of the formed active layer on the physio-chemical properties of the membrane including water contact angle, water content, flux and sodium sulfate rejection, porosity, mean pore size, heavy metal rejection and anti-fouling performance was investigated. 

 The obtained results revealed that the surface-modified membrane with 1 % (by wt)  MM-0.5% (by wt) GO-NPs had a more appropriate separation performance and better antifouling properties compared to other membranes. SEM images of the cross-sectional area of the membranes showed the formation of a relatively uniform layer on the membrane surface, which became more dense with increase in the amount of GO-Nps. The performance of the modified membrane in the removal of Cu and Cr heavy metal ions was also evaluated and compared with the pristine membrane. The removal percentage of Cu and Cr ions was 51.4% and 49.3% for the neat membrane, whereas it was 81.7% and 75.3% for the superior modified membrane, respectively. Moreover, the total fouling resistance was measured to be 23% for the virgin membrane, while it was 13.2% (Pvalue<0.05) for the best modified one. The irreversible fouling parameter was obviously decreased from 20% for the pristine membrane to 3.2% for the optimum modified membrane that shows  a superior antifouling ability for them.