Two surface functionalization techn

Two surface functionalization techniques (dip-coating and filtration-assisted) were used for membrane surface function- alization using pDA and Cu-MOF. Both techniques providedsuccessful immobilization of Cu-MOF and pDA on the membrane surface, which resulted in higher surface hydro-philicity and negative surface charge; however, fil-coated membranes showed a higher surface roughness due to pDA agglomeration upon dynamic fabrication. The functionalization using only a pDA layer showed improvement in membrane rejection by providing more mass transport resistance. In addition, due to the hydrophilic nature of pDA, the dip-coated and fil-coated membranes showed enhanced antifouling properties compared to those of the blank TFC membrane. The drawback of pDA functionalization was flux reduction dueto the dense polymerized layer on the membrane surface. However, the addition of Cu-MOF to both the fil-MOF-coated membrane and the dip-MOF-coated membranes compensated for the flux reduction by increasing the surface hydrophilicity and providing more water pathways due to the porous structure of MOFs. The MD simulation revealed the adsorption energy of MB (−27 kcal/mol) and MO (591 kcal/mol) with the embedded Cu-MOF to confirm the effect of Cu-MOF on enhanced surface charge and therefore enhanced MO dye rejection.