posted on 2022-01-03, 22:14authored byJing Yang, Xinran Zhu, Jingjing Lin, Qiqi Wang, Luqing Zhang, Ning Yang, Ligang Lin, Junqiang Zhao, Yiping Zhao, Li Chen
Membrane
biofouling, adhesion of microorganisms on the surface
and the subsequent formation of a biofilm, remains a persistent and
inevitable issue, which results in a dramatic reduction of permeability
and lifespan. Constructing a membrane with active bacteria-killing
and passive anti-adhesion properties is still a challenge to mitigate
membrane biofouling. Herein, an active–passive anti-biofouling
membrane was originally fabricated by integration of hydrophilic hyperbranched
poly(N-acryloylmorpholine) (HPA) and the dimethylaminoethyl
acrylate–dodecylammonium bromide (DD) quaternary ammonium compound.
Inspired by modern dopamine biomimetic adhesion chemistry, thiolated
HPA was first immobilized on the polydopamine (PD)-modified poly(vinylidene
fluoride) membrane surface through Michael addition, followed by conjugation
of DD via a thiol–ene click reaction. The membrane surface
changes of the chemical structure, hydrophilicity, and zeta potential
proved that bacteria-killing DD and the anti-adhesion HPA layer were
successively conjugated. The initial contact angle of the M-PD/HPA/DD
membrane was reduced from 120.5° for the pure membrane to 52.3°.
Furthermore, the water flux of the M-PD/HPA/DD membrane increased
from 318.9 L m–2 h–1 (0.02 MPa)
for the pure membrane to 854.4 L m–2 h–1. In addition, the M-PD/HPA/DD membrane exhibited excellent active
bacteria-killing property with inhibition rates of ∼90% for Escherichia coli and ∼95% for Staphylococcus aureus, respectively. Meanwhile, in
the filtration of artificial bacteria wastewater, the M-PD/HPA/DD
membrane showed a higher water flux recovery rate of 86.9% than 43.3%
for the pure membrane, indicating an excellent anti-biofouling property.
Therefore, this molecular-level design approach for the modification
of the membrane surface could significantly enhance permeability and
mitigate membrane biofouling, which provides a promising dimension
for the preparation of the anti-biofouling membrane.