Phase transited lysozyme particles and MoS₂ nanosheets modified elastomer-like antibacterial and antifouling microfiltration membrane derived from poly(ethylene-co-methyl acrylate)/poly(vinylidene fluoride) (EMA/PVDF) blend for water purification application

Phase inversion is a widely exploited membrane preparation method and a workhorse in the membrane industries. Notwithstanding its expansive utility, this method is limited to polymers that are soluble in organic solvents. In the current study, a microfiltration membrane was prepared from the poly(ethylene-co-methyl acrylate)/poly(vinylidene fluoride) (EMA/PVDF) blend by selective etching, a recently introduced membrane preparation technique used for polymers that are chemically resistant to the common organic solvents. The developed membrane surfaces were modified with two structurally different antibacterial agents: phase-transited lysozyme (PTL) and MoS₂ nanosheets. PTL nanoparticles were deposited over the membrane by dip-coating, whereas MoS₂ nanosheets were decorated on the membrane by vacuum filtration followed by chitosan dip-coating. The surface-modified membrane exhibited extensive antibacterial and antifouling properties. Antibacterial properties were studied against bacteria viz. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and PTL-derived membrane were observed to have the highest reduction in bacterial growth against E. coli (98.14%) and S. aureus (93.64%). Inline bacterial filtration study demonstrated high separation efficiency of the modified membranes as there were no significant traces of bacteria even after 200 h of the experiment. Antifouling properties of MoS₂ derived membranes (flux recovery ratio (FRR) = 88%) were superior to those of control and PTL-coated membranes (FRR = 63%). Additionally, the elastomer-like behavior of EMA copolymer helped retain the initial membrane flux for three consecutive days indicating high compaction resistance of the membrane. Hence, the developed EMA membrane is anticipated to be a potential microfiltration candidate for water purification applications.